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  Subjects -> METEOROLOGY (Total: 81 journals)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 2)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 6)
Advances in Climate Change Research     Open Access  
Advances in Meteorology     Open Access   (Followers: 5)
Aeolian Research     Hybrid Journal   (Followers: 3)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 7)
American Journal of Climate Change     Open Access   (Followers: 7)
Asian Journal of Earth Sciences     Open Access   (Followers: 20)
Atmósfera     Open Access  
Atmosphere     Open Access   (Followers: 4)
Atmosphere-Ocean     Full-text available via subscription   (Followers: 7)
Atmospheric Chemistry and Physics (ACP)     Open Access   (Followers: 13)
Atmospheric Chemistry and Physics Discussions (ACPD)     Open Access   (Followers: 7)
Atmospheric Research     Hybrid Journal   (Followers: 19)
Atmospheric Science Letters     Hybrid Journal   (Followers: 8)
Boundary-Layer Meteorology     Hybrid Journal   (Followers: 10)
Bulletin of the American Meteorological Society     Open Access   (Followers: 14)
Carbon Balance and Management     Open Access   (Followers: 5)
Change and Adaptation in Socio-Ecological Systems     Open Access  
Climate     Open Access   (Followers: 2)
Climate Change Economics     Hybrid Journal   (Followers: 16)
Climate Change Responses     Open Access  
Climate Dynamics     Hybrid Journal   (Followers: 14)
Climate law     Hybrid Journal   (Followers: 3)
Climate of the Past (CP)     Open Access   (Followers: 4)
Climate of the Past Discussions (CPD)     Open Access   (Followers: 2)
Climate Policy     Hybrid Journal   (Followers: 22)
Climate Risk Management     Open Access  
Climatic Change     Hybrid Journal   (Followers: 33)
Current Climate Change Reports     Hybrid Journal  
Developments in Atmospheric Science     Full-text available via subscription   (Followers: 4)
Dynamics of Atmospheres and Oceans     Hybrid Journal   (Followers: 3)
Earth Perspectives - Transdisciplinarity Enabled     Open Access   (Followers: 1)
Energy & Environment     Full-text available via subscription   (Followers: 17)
Environmental and Climate Technologies     Open Access   (Followers: 2)
Global Meteorology     Open Access  
International Journal of Atmospheric Sciences     Open Access   (Followers: 4)
International Journal of Biometeorology     Hybrid Journal   (Followers: 1)
International Journal of Climate Change Strategies and Management     Hybrid Journal   (Followers: 9)
International Journal of Climatology     Hybrid Journal   (Followers: 15)
International Journal of Image and Data Fusion     Hybrid Journal   (Followers: 1)
Journal of Applied Meteorology and Climatology     Full-text available via subscription   (Followers: 8)
Journal of Atmospheric and Oceanic Technology     Full-text available via subscription   (Followers: 11)
Journal of Atmospheric and Solar-Terrestrial Physics     Hybrid Journal   (Followers: 15)
Journal of Atmospheric Chemistry     Hybrid Journal   (Followers: 2)
Journal of Climate     Full-text available via subscription   (Followers: 27)
Journal of Climatology     Open Access   (Followers: 1)
Journal of Hydrology and Meteorology     Open Access   (Followers: 4)
Journal of Hydrometeorology     Full-text available via subscription   (Followers: 3)
Journal of Integrative Environmental Sciences     Hybrid Journal   (Followers: 4)
Journal of Meteorology and Climate Science     Full-text available via subscription   (Followers: 1)
Journal of Space Weather and Space Climate     Open Access   (Followers: 5)
Journal of the Atmospheric Sciences     Full-text available via subscription   (Followers: 27)
Journal of Weather Modification     Full-text available via subscription  
Large Marine Ecosystems     Full-text available via subscription  
Meteorologica     Open Access  
Meteorological Applications     Hybrid Journal   (Followers: 1)
Meteorologische Zeitschrift     Full-text available via subscription   (Followers: 2)
Meteorology and Atmospheric Physics     Hybrid Journal   (Followers: 5)
Mètode Science Studies Journal : Annual Review     Open Access  
Michigan Journal of Sustainability     Open Access  
Monthly Notices of the Royal Astronomical Society     Hybrid Journal   (Followers: 2)
Monthly Notices of the Royal Astronomical Society Letters     Hybrid Journal   (Followers: 3)
Monthly Weather Review     Full-text available via subscription   (Followers: 13)
Nature Climate Change     Full-text available via subscription   (Followers: 41)
Nature Reports Climate Change     Full-text available via subscription   (Followers: 17)
Open Journal of Modern Hydrology     Open Access   (Followers: 3)
Revista Brasileira de Meteorologia     Open Access   (Followers: 1)
Russian Meteorology and Hydrology     Hybrid Journal   (Followers: 4)
Space Weather     Full-text available via subscription   (Followers: 3)
Studia Geophysica et Geodaetica     Hybrid Journal   (Followers: 3)
Tellus A     Open Access   (Followers: 4)
Tellus B     Open Access   (Followers: 6)
The Cryosphere (TC)     Open Access   (Followers: 2)
The Cryosphere Discussions (TCD)     Open Access   (Followers: 1)
The Quarterly Journal of the Royal Meteorological Society     Hybrid Journal   (Followers: 7)
Theoretical and Applied Climatology     Hybrid Journal   (Followers: 2)
Weather     Hybrid Journal   (Followers: 2)
Weather and Climate Extremes     Open Access   (Followers: 2)
Weather and Forecasting     Full-text available via subscription   (Followers: 2)
Weatherwise     Hybrid Journal  
气候与环境研究     Full-text available via subscription  
Journal Cover   Journal of Atmospheric and Solar-Terrestrial Physics
  [SJR: 1.045]   [H-I: 61]   [15 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1364-6826
   Published by Elsevier Homepage  [2812 journals]
  • Extreme stratospheric springs and their consequences for the onset of
           polar mesospheric Clouds
    • Abstract: Publication date: Available online 26 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): David E. Siskind , Douglas R. Allen , Cora E. Randall , V. Lynn Harvey , Mark E. Hervig , Jerry Lumpe , Brentha Thurairajah , Scott M. Bailey , James M. Russell
      We use data from the Aeronomy of Ice in the Mesosphere (AIM) explorer and from the NASA Modern Era Retrospective Analysis for Research and Applications (MERRA) stratospheric analysis to explore the variability in the onset of the Northern Hemisphere (NH) Polar Mesospheric Cloud (PMC) season. Consistent with recently published results, we show that the early onset of the NH PMC season in 2013 was accompanied by a warm springtime stratosphere; conversely, we show that the late onset in 2008 coincides with a very cold springtime stratosphere. Similar stratospheric temperature anomalies for 1997 and 2011 also are connected either directly, through observed temperatures, or indirectly, through an early PMC onset, to conditions near the mesopause. These 4 years, 2008, 1997, 2011, and 2013 represent the extremes of stratospheric springtime temperatures seen in the MERRA analysis and correspond to analogous extrema in planetary wave activity. The three years with enhanced planetary wave activity (1997, 2011 and 2013) are shown to coincide with the recently identified stratospheric Frozen In Anticyclone (FrIAC) phenomenon. FrIACs in 1997 and 2013 are associated with early PMC onsets; however, the dramatic FrIAC of 2011 is not. This may be because the 2011 FrIAC occurred too early in the spring. The link between NH PMC onset and stratospheric FrIAC occurrences represents a new mode of coupling between the stratosphere and mesosphere. Since FrIACs appear to be more frequent in recent years, we speculate that as a result, PMCs may occur earlier as well. Finally we compare the zonal mean zonal winds and observed gravity wave activity for the FrIACs of 2011 and 2013. We find no evidence that gravity wave activity was favored in 2013 relative to 2011, thus suggesting that direct forcing by planetary waves was the key mechanism in accelerating the cooling and moistening of the NH mesopause region in May of 2013.


      PubDate: 2015-06-30T10:52:34Z
       
  • Application of aerosol optical properties to estimate aerosol type from
           ground-based remote sensing observation at urban area of northeastern
           China
    • Abstract: Publication date: Available online 27 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Huizheng Che , Hujia Zhao , Yunfei Wu , Xiangao Xia , Jun Zhu , Oleg Dubovik , Victor Estelles , Yanjun Ma , Yangfeng Wang , Hong Wang , Yaqiang Wang , Xiaoye Zhang , Guangyu Shi
      Aerosol optical properties were derived from ground-based sunphotometer observations between 2009-2013 at three urban sites of Shenyang, Anshan, Fushun in northeastern China. The annual means for extinction aerosol optical depths (EAOD) at 500nm were 0.57±0.38, 0.52±0.35, and 0.41±0.31 at Shenyang, Anshan, Fushun, respectively. The corresponding annual means for the extinction Angstrom exponents (EAE) computed for the wavelengths of 440 and 870nm were 0.86±0.32, 0.86±0.34 and 0.91±0.35, respectively, indicating that urban area of Northeast China were affected by both coarse and fine particles. Hygroscopic growth in summer and incursions of dust aerosols in spring were evidently revealed from the analysis of the relationship between EAE and δEAE (the EAE difference, δEAE=EAE(440,670)- EAE(670,870)). The annual mean absorption aerosol optical depths (AAOD440nm) values at Shenyang, Anshan, Fushun were 0.15±0.11, 0.10±0.07, 0.08±0.04, respectively. The annual mean absorption Angstrom exponents (AAE440-870nm) values were 0.86±0.24, 1.19±0.39, 1.33±0.36 at Shenyang, Anshan, Fushun, respectively. When the AAEs were close to unity at Anshan, the absorption aerosol particles evidently consisted of black carbon from coal combustion and motor vehicles. Larger AAEs at Fushun were indicative of absorbing aerosols mainly from biomass burning and mineral dust. The AAE at Shenyang was<1 which may be consistent with black carbon particles with absorbing or non-absorbing coatings. Analysis of the relationship between the AAEs and extinction Angstrom exponents showed that the aerosol populations at these three sites could be classified as “mixed-small particles” including anthropogenic particles and secondary organic aerosol with highly variable sphericity fractions.


      PubDate: 2015-06-30T10:52:34Z
       
  • X-rays and microwave RF power from High voltage laboratory sparks
    • Abstract: Publication date: Available online 22 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Joan Montanyà , Ferran Fabró , Víctor March , Oscar van der Velde , Glòria Solà , David Romero , Oriol Argemí
      Lightning flashes involve high energy processes that still are not well understood. In the laboratory, high voltage pulses are used to produce long sparks in open air allowing the production of energetic radiation. In this paper X-rays emitted by long sparks in air are simultaneously measured with the RF power radiation at 2.4GHz. The experiment showed that the measured RF power systematically peaks at the time of the X-rays generation (in the microsecond time scale). All of the triggered sparks present peaks of RF radiation before the breakdown of the gap. The RF peaks are related to the applied voltage to the gap. RF peaks are also detected in discharges without breakdown. Cases where X-rays are detected presented higher RF power. The results indicate that at some stage of the discharge, before the breakdown, electrons are very fast accelerated letting in some cases to produce X-rays. Microwave radiation and X-rays may come from the same process.


      PubDate: 2015-06-25T11:12:12Z
       
  • Review and Testing Analysis of Moupfouma rain rate Model for Southern
           India
    • Abstract: Publication date: Available online 24 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Chandrika P , Vijaya Bhaskara Rao S , Kiran Kumar N.V.P , Narayana Rao T
      Suitability of the analytical model by Moupfouma in modeling the one-minute rain rate distributions at tropical stations of Thiruvananthapuram and Gadanki is studied. The Climatic dependent parameters of the model governing the slope of the one-minute rain rate distributions are acclimatized and validated. The paper also presents rain rate distributions for Thiruvananthapuram and Gadanki. Performance of the model with newly refined climatic dependent parameters is assessed. The Moupfouma model is observed to model the one minute rain rate distributions with a maximum percentage relative error of 14% at 0.001% of time, and with approximately zero relative error at 0.01% of time in an average year. The climatic dependent parameters governing the slope of one-minute rain rate distributions are proposed for Southern India.


      PubDate: 2015-06-25T11:12:12Z
       
  • Analysis of aerosol scattering properties measured by a nephelometer at a
           coastal-rural site in the Atlantic southwest of the Iberian Peninsula
    • Abstract: Publication date: Available online 24 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Juan F. López , Victoria E. Cachorro , Angel M. de Frutos
      Aerosol hemispherical scattering and the backscattering coefficients, σsp, σbsc, have been measured using a 3-wavelength(450, 550 and 700nm) integrating nephelometer over two years (January 2006 to May 2008) in the coastal area of the Gulf of Cádiz, in the southwest of the Iberian Peninsula. These coefficients have been carefully analyzed starting with the impact of corrections on the measurements of σsp: i.e., drift calibration constants do not modify the mean value in our data series. However, the selection of dry data (with RH less than 50%) modifies substantially the number of data and the resulting mean value of σsp is now 14% lower, which is compensated when the angular truncation correction is applied. The characterization and features of σsp, σbsc, and the derived parameters αsp (alpha Ångström exponent) and b (the backscatter ratio) has been analysed, as annual, seasonal and diurnal evolution. A general statistic based on hourly data gives mean values and standard deviation of σsp (500 nm) = 48 ±38Mm−1 with a median of 38 Mm-1, and σbsc(500nm)=5.6±3.8Mm-1 with a median of 4.6 Mm-1. Thus, these values show moderate-low values but with a large range of variation considering the existing measured values over the Iberian Peninsula. The median value of σsp (500nm) is an indicator that events of high aerosol burden are frequent presenting a substantial influence on the daily averages. The alpha Ångström exponent, αsp, derived from the pairs 450/700 nm gives a mean value 1.35±0.54 with a median of 1.47 and with the most frequent value of 1.7, thus indicating the prevalence of medium size particles but with a significant influence of fine particles. The b ratio has the same value for mean and median, 0.12±0.02, showing a decrease with increasing values of σsp. Annual and daily cycles have been also analyzed showing the complex behaviour of the optical properties at this coastal site where cold and warn periods show very different characteristics. Besides, the daily cycle is strongly influenced by the breeze conditions. According to the information extracted from the σsp-αsp relationship this rural Atlantic site presents prevalence of mixed marine-continental aerosols but with significant influence of local anthropogenic sources. Desert dust particles were also discriminated which are not frequently reported in the data of “in situ” aerosols.


      PubDate: 2015-06-25T11:12:12Z
       
  • IFC-Ed. board
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131




      PubDate: 2015-06-25T11:12:12Z
       
  • A statistical study of internal gravity wave characteristics using the
           combined Irkutsk incoherent scatter radar and Digisonde data
    • Abstract: Publication date: Available online 24 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): A.V. Medvedev , K.G. Ratovsky , M.V. Tolstikov , S.S. Alsatkin , A.A. Shcherbakov
      Using previously developed methods for determining the three-dimensional spatial-temporal structure of traveling ionospheric disturbances and the automatic detection of wave disturbances, we analyzed data obtained simultaneously with the Irkutsk Incoherent Scatter Radar and Irkutsk ionosonde. The analysis relies on long continuous series of observations acquired during winter seasons in 2010–2014. We obtained representative statistics of traveling ionospheric disturbances characteristics including the full velocity vector. We analyzed the characteristics of traveling ionospheric disturbances with 1–6 hour periods comparing them against the dispersion relations for internal gravity waves in the Boussinesq and Hines approximations. It was shown that, with due consideration for the horizontal neutral wind, most of the observed ionospheric disturbances agrees with the laws of internal gravity waves propagation in the upper atmosphere. It was found that azimuthal anisotropy of internal gravity waves characteristics allows us to obtain the diurnal variations of zonal and meridional neutral winds in the upper atmosphere.


      PubDate: 2015-06-25T11:12:12Z
       
  • Characteristics of second-order residual ionospheric error in GNSS radio
           
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Xiaochuan Qu , Zhenghang Li , Jiachun An , Wenwu Ding
      In Global Navigation Satellite Systems (GNSS) radio occultation (RO), one of the most significant error sources is the ionospheric error, which is largely eliminated by dual-frequency linear combination. However, second-order residual ionospheric error (RIE) in excess phase still remains and affects the retrievals of neutral atmospheric parameters in RO. Second-order RIE varies with RO azimuth in a sinusoidal pattern for a set of simulated RO events occurring in the same location at different azimuths. The amplitude of the sinusoidal curve below 60km is at the order of sub-centimeter under moderate solar activity level. The retrieval biases of the neutral atmospheric parameters induced by second-order RIE also have sinusoidal features with RO azimuth, but have opposite variation trends to that of the second-order RIE. The RO azimuths of the maximum positive and negative retrieval biases correspond approximately to the azimuths of maximum negative and positive second-order RIEs, respectively. The order of the maximum bending angle bias induced by the second-order RIE is about 10−8 rad under moderate solar activity level. However, the retrieval errors at low latitude are larger than those at high and middle latitudes, and the maximum temperature bias at low latitude could be 0.35K at 40km. Based on the sinusoidal variation of second-order RIE, it is shown that even at the same RO point and under the same solar activity level, the second-order RIEs at different RO azimuths still have different effects on the retrieval precision of atmospheric parameters. This should be considered carefully when many RO profiles are averaged for climate trend detection, especially at low latitude.


      PubDate: 2015-06-20T13:39:38Z
       
  • Plasma bubble monitoring by TEC map and 630nm airglow image
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): H. Takahashi , C.M. Wrasse , Y. Otsuka , A. Ivo , V. Gomes , I. Paulino , A.F. Medeiros , C.M. Denardini , N. Sant’Anna , K. Shiokawa
      Equatorial ionosphere plasma bubbles over the South American continent were successfully observed by mapping the total electron content (TECMAP) using data provided by ground-based GNSS receiver networks. The TECMAP could cover almost all of the continent within ~4000km distance in longitude and latitude, monitoring TEC variability continuously with a time resolution of 10min. Simultaneous observations of OI 630nm all-sky image at Cachoeira Paulista (22.7°S, 45.0°W) and Cariri (7.4°S, 36.5°W) were used to compare the bubble structures. The spatial resolution of the TECMAP varied from 50km to 1000km, depending on the density of the observation sites. On the other hand, optical imaging has a spatial resolution better than 15km, depicting the fine structure of the bubbles but covering a limited area (~1600km diameter). TECMAP has an advantage in its spatial coverage and the continuous monitoring (day and night) form. The initial phase of plasma depletion in the post-sunset equatorial ionization anomaly (PS-EIA) trough region, followed by development of plasma bubbles in the crest region, could be monitored in a progressive way over the magnetic equator. In December 2013 to January 2014, periodically spaced bubble structures were frequently observed. The longitudinal spacing between the bubbles was around 600–800km depending on the day. The periodic form of plasma bubbles may suggest a seeding process related to the solar terminator passage in the ionosphere.


      PubDate: 2015-06-20T13:39:38Z
       
  • Statistical functions and relevant correlation coefficients of clearness
           index
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Diego Pavanello , Willem Zaaiman , Alessandra Colli , John Heiser , Scott Smith
      This article presents a statistical analysis of the sky conditions, during years from 2010 to 2012, for three different locations: the Joint Research Centre site in Ispra (Italy, European Solar Test Installation – ESTI laboratories), the site of National Renewable Energy Laboratory in Golden (Colorado, USA) and the site of Brookhaven National Laboratories in Upton (New York, USA). The key parameter is the clearness index k T , a dimensionless expression of the global irradiance impinging upon a horizontal surface at a given instant of time. In the first part, the sky conditions are characterized using daily averages, giving a general overview of the three sites. In the second part the analysis is performed using data sets with a short-term resolution of 1 sample per minute, demonstrating remarkable properties of the statistical distributions of the clearness index, reinforced by a proof using fuzzy logic methods. Successively some time-dependent correlations between different meteorological variables are presented in terms of Pearson and Spearman correlation coefficients, and introducing a new one.


      PubDate: 2015-06-20T13:39:38Z
       
  • Lidar observations of cirrus clouds in Buenos Aires
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): S. Gabriela Lakkis , Mario Lavorato , Pablo Canziani , Hector Lacomi
      Characterization of cirrus clouds over Buenos Aires (34.6°S, 58.5°W) using a ground based lidar is presented. The study, carried out for the period 2010–2011, reveals that cirrus are usually found in the altitude region 8–11km, with mid-cloud temperatures values varying between −75°C and 55°C. The clouds, whose bases altitudes display significant variability while their tops remains close to the tropopause, show geometrical thickness ranging from 1.2 to 5km, with on average value 3.0±0.9km. Most commonly observed cirri can be characterized as optically thin cirrus rather than dense ones, with a mean optical depth value of 0.26±0.11 and an applied multiple scattering factor η of 0.85±0.07. In this region, the optical depth increases with increasing geometrical thickness with a partially linear correlation. Lidar ratios are also analyzed and on average the value is 32±17sr.


      PubDate: 2015-06-20T13:39:38Z
       
  • Sensitivity of tropical stratospheric ozone to rotational UV variations
           estimated from UARS and Aura MLS observations during the declining phases
           of solar cycles 22 and 23
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Sébastien Bossay , Slimane Bekki , Marion Marchand , Virginie Poulain , Ralf Toumi
      The correlation between tropical stratospheric ozone and UV radiation on solar rotational time scales is investigated using daily satellite ozone observations and reconstructed solar spectra. We consider two 3-year periods falling within the descending phases of two 11-year solar cycles 22 (1991–1994) and 23 (2004–2007). The UV rotational cycle is highly irregular and even disappears for half a year during cycle 23. For the 1991–1994 period, ozone and 205nm UV flux are found to be correlated between about 10 and 1hPa with a maximum of 0.29 at ~5hPa; ozone sensitivity (percentage change in ozone for 1% change in UV) peaks at ~0.4. Correlation during cycle 23 is weaker with a peak ozone sensitivity of 0.2. The correlation is found to vary widely, not only with altitude, but also from one year to the next with a rotational signal in ozone appearing almost intermittent. Unexpectedly, the correlation is not found to bear any relation with the solar rotational forcing. For instance, solar rotational fluctuations are by far the strongest during 1991–1992 whereas the correlation peaks at the end of 1993, a rotationally quiescent period. When calculated over sliding intervals of 1-year, the sensitivity is found to vary very strongly within both 3-year periods; it is almost negligible over the entire vertical profile during some 1-year intervals or reaches close to 1 around 2–5mb for other intervals. Other sources of variability, presumably of dynamical origin, operate on the rotational spectral range and determine to a large extent the estimated solar rotational signal. Even considering 3 years of observations (corresponding to about 40 solar cycles), the extraction of the rotational solar signal does not appear to be robust during declining phases of 11-year solar cycles. As observational studies cover at best three 11-year solar cycles, it must be challenging to produce a reliable estimation of the 11-year solar cycle signal in stratospheric ozone, especially in the presence of decadal climate variability.


      PubDate: 2015-06-20T13:39:38Z
       
  • Solar global horizontal and direct normal irradiation maps in Spain
           derived from geostationary satellites
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): J. Polo
      Solar radiation derived from satellite imagery is a powerful and highly accurate technique for solar resource assessment due to its maturity and to the long term database of observation images available. This work presents the methodology developed at CIEMAT for mapping solar radiation from geostationary satellite information and it also shows solar irradiation maps of global horizontal and direct normal components elaborated for Spain. The maps presented here have been developed from daily solar irradiation estimated for eleven years of satellite images (2001–2011). An attempt to evaluate the uncertainty of the presented maps is made using ground measurements from 27 meteorological stations available in Spain for global horizontal irradiation obtained from the World Radiation Data Centre. In the case of direct normal irradiation the ground measurement database was scarce, having available only six ground stations with measurements for a period of 4 years. Yearly values of global horizontal irradiation are around 1800kWhm−2 in most of the country and around 1950–2000kWhm−2 for annual direct normal irradiation. Root mean square errors in monthly means were of 11% and of 29% for global horizontal and direct normal irradiation, respectively.


      PubDate: 2015-06-20T13:39:38Z
       
  • Determining magnetotail reconnection location from polar rain energy
           dispersion
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Yongliang Zhang , Simon Wing
      An improved algorithm was developed to estimate the polar rain electron path length from the magnetotail X-line to the polar ionosphere using the information of polar rain electron energy-latitude dispersion. Recent particle tracing simulations using APLOPM model (Applied Physics Laboratory – Open-field line particle Precipitation Model) (Wing et al., 2001 ; Wing and Zhang, 2015) indicate that an existing or traditional method underestimates the path length by at least 33%. A new method for estimating electron path length that introduces a new parameter (energy parameter) is proposed. The improved algorithm has been validated using the APLOPM simulation data. By applying the new algorithm to two real events measured by DMSP satellites, we found the polar rain electron path lengths of 67 and 114 R E, (X-lines estimated at X=−54 and −91 R E), respectively (assuming the distance from the X-line to the Earth is 80% of the electron path length). The associated IMF Bz were 1 and –11nT, respectively for the two events. This is consistent with the expected stretched magnetotail configuration under a strongly southward IMF. The results are also consistent with statistical results of the X-line locations from Geotail measurements.


      PubDate: 2015-06-20T13:39:38Z
       
  • Gravity waves-induced airglow temperature variations, phase relationships,
           and Krassovsky ratio for OH(8,3) airglow, O2(0,1) atmospheric band, and
           O(1S) greenline in the MLT region
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Tai-Yin Huang
      The gravity wave-induced secular variations and fluctuations of airglow intensity-weighted temperatures for OH(8,3) nightglow, O2(0,1) atmospheric band, and O(1S) greenline in the MLT region were simulated to study the wave effects’ on airglow temperatures. They were investigated with a time-dependent OH Chemistry-Dynamics (OHCD) model and a Multiple Airglow Chemistry-Dynamics (MACD) model with a small-scale linear gravity wave packet. The largest wave-induced airglow temperature secular variations are found to be ~0.8% in the O2(0,1) temperature and the largest wave-induced airglow temperature fluctuations are found to be ~0.25% in the O(1S) temperature. We also investigated the phase relationships between the airglow intensities and temperatures. Our results show that the airglow intensities lead the airglow temperatures most of the time. Also, airglow located at a higher altitude leads the airglow located at a lower altitude, indicating a downward phase progression, which is consistent with the phase of the wave packet we used. The Krassovsky ratio for these airglow emissions were calculated and found to be decreasing with increasing altitude. The amplitude of the Krassovsky ratio for OH(8,3) airglow, O2(0,1) atmospheric band, and O(1S) greenline were ~10, 6, and 4, respectively.


      PubDate: 2015-06-20T13:39:38Z
       
  • Synoptic Kelvin type perturbation waves over Congo basin over the period
           1979–2010
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Zebaze Sinclaire , André Lenouo , Clément Tchawoua , Serge Janicot
      The synoptic structure and inter-annual variability of Kelvin waves over the Congo basin from 1979 to 2010 are explored using outgoing longwave radiation (OLR) and National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis data. Composite method shows that high values of synoptic Kelvin wave (SKW) index are located over Congo basin during March–June where the convective active phase favours the formation of convective synoptic systems. Mean composite SKWs structure shows that these waves propagate faster over land surface and dissipate with suppressed phase. Because convective instability is smaller, these waves cannot grow in Congo basin. High correlation between SKWs and precipitation time series occurs when the Kelvin waves lead the precipitation time series by about 4 days. The analysis of 32 years datasets (1979–2010) also shows that in some particular year, strong SKWs propagation exists with periods centred around 5 days. Otherwise, results show marked inter-annual variability of Kelvin wave activity over Congo basin associated with divergence and low level westerly trade winds.


      PubDate: 2015-06-20T13:39:38Z
       
  • Variability of the quasi-2-day wave and interaction with longer period
           
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): A. Guharay , P.P. Batista , B.R. Clemesha
      An exclusive study has been carried out with long term meteor wind data (2000–2014) to characterize the quasi-2-day wave (QTDW) in the mesosphere and lower thermosphere (MLT) and its interactions with the longer period planetary waves at Cachoeira Paulista (22.7°S, 45°W). The QTDW is observed to be dominant during late summer (January–February) all the years under consideration except 2013. All the wave parameters exhibit significant interannual variability. The maximum wave amplitude comes out to be 39m/s, which is significantly higher than the reported northern hemispheric findings. The mean MLT period exhibits a wide range of variability (36–70h) indicating the presence of multiple Rossby normal modes with varying zonal wave numbers. Modulations of the QTDW amplitude by the planetary waves with longer periodicities (>9 days) are evident, especially during summer. The nonlinear interactions between the 2-day wave and longer period waves are believed to give rise to a host of secondary waves with frequencies lying close to 2-day. The strong QTDW activity, as observed at this location, has potential to cause significant effect on the overlying ionosphere and hence the atmosphere-ionosphere dynamical coupling.


      PubDate: 2015-06-20T13:39:38Z
       
  • Simultaneous retrieval of T(p) and CO2 VMR from two-channel non-LTE limb
           radiances and application to daytime SABER/TIMED measurements
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): L. Rezac , A. Kutepov , J.M. Russell III , A.G. Feofilov , J. Yue , R.A. Goldberg
      The kinetic temperature, T k , and carbon dioxide, CO2 density, are key parameters that characterize the energetics and dynamics of the mesosphere and lower thermosphere (MLT) region. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on-board the Thermosphere-Ionosphere-Mesosphere-Energetics and Dynamics (TIMED) satellite has been providing global, simultaneous measurements of limb radiance in 10 spectral channels continuously since late January 2002. In this paper we (1) present a methodology for a self-consistent simultaneous retrieval of temperature/pressure, T k (p), and CO2 volume mixing ratio (VMR) from the broadband infrared limb measurements in the 15 and 4.3 μ m channels, and (2) qualitatively describe the first results on the CO2 VMR and T k obtained from application of this technique to the SABER 15 and 4.3 μ m channels, including issues, which demand additional constraints to be applied. The self-consistent two-channel retrieval architecture updates parameters at all altitudes simultaneously, and it is built upon iterative switching between two retrieval modules, one for CO2 and one for T k . A detailed study of sensitivity, stability and convergence was carried out to validate the algorithm. The T k /CO2 VMR distribution can be reliably retrieved without biases connected with this non-linear inverse problem starting with an initial guess as far as ±20% of CO2 VMR and ±15K from the solution (as global shift, or somewhat larger if only local deviations are considered). In polar summer toward high latitudes the retrieved CO2 VMR profile shows a local peak around 90km. We discuss details of this feature and show that: (a) it is not an algorithm artifact or instability, (b) additional a priori constraints are needed in order to obtain a physical profile and to remove this peak, and (c) several possibilities are explored as to uncover the real cause of this feature, but no firm conclusion can be reached at this time. This algorithm has been applied to all available daytime SABER measurements since 2002, and the first results of the mean CO2 VMR profiles and their distribution is discussed. In particular, the CO2 VMR profiles depart from a well mixed value at altitudes of 65–70km during equinoxes at high and mid-latitudes, but in the summer hemisphere solstice period the SABER data is more consistent with a well mixed VMR conditions extend up to 87–90km especially toward high latitudes.


      PubDate: 2015-06-20T13:39:38Z
       
  • Wavelength dependence of the effective cloud optical depth
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): D. Serrano , M.J. Marín , M. Núñez , M.P. Utrillas , S. Gandía , J.A. Martínez-Lozano
      This study examines the wavelength dependence of cloud optical depth. To accomplish this task two different wavelength bands of the solar spectrum were considered in the cloud optical depth retrieval which was conducted in Valencia, Spain. The first retrieval used global irradiance measurements in the UVER range taken from a YES-UVB-1 radiometer in combination with multiple scattering model estimates; while the second retrieval was obtained in the Broadband range, with measurements of global solar surface irradiance from a CM6 pyranometer and a multiple scattering model. Whilst the dependence of the cloud optical depth (τ) on the wavelength is small, the best result was displayed by the SBDART model with less than 2% deviation between two ranges and moderately worse results were obtained with the LibRadtran model. Finally, seasonal statistical data for optical depth are presented for 2011 and 2012.


      PubDate: 2015-06-20T13:39:38Z
       
  • Ionospheric electron density profile estimation using commercial AM
           broadcast signals
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): De Yu , Hong Ma , Li Cheng , Yang Li , Yufeng Zhang , Wenjun Chen
      A new method for estimating the bottom electron density profile by using commercial AM broadcast signals as non-cooperative signals is presented in this paper. Without requiring any dedicated transmitters, the required input data are the measured elevation angles of signals transmitted from the known locations of broadcast stations. The input data are inverted for the QPS model parameters depicting the electron density profile of the signal’s reflection area by using a probabilistic inversion technique. This method has been validated on synthesized data and used with the real data provided by an HF direction-finding system situated near the city of Wuhan. The estimated parameters obtained by the proposed method have been compared with vertical ionosonde data and have been used to locate the Shijiazhuang broadcast station. The simulation and experimental results indicate that the proposed ionospheric sounding method is feasible for obtaining useful electron density profiles.


      PubDate: 2015-06-20T13:39:38Z
       
  • Studying the G condition occurrence in different latitudes under solar
           minimum: Observation and modeling
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Polekh N.M. , Romanova E.B. , Ratovsky K.G. , Shi J.K. , Wang X. , Wang G.J.
      We analyzed the G condition occurrence, using data of ionospheric vertical sounding from stations Norilsk (69.4°N, 88.1°Е), Irkutsk (52.5°N, 104°Е) and Hainan (18.3°N, 109.3°Е) during the last extreme low solar activity period (2006–2009). In most cases, the three stations registered the G condition in May–August; in Norilsk, however, it was registered in March–April 2008. Under quiet geomagnetic conditions, the longest intervals (up to several hours) during which the G condition was continuously registered were observed in Irkutsk and Norilsk in June–July 2008. In Norilsk, it was registered almost every day in the morning and in the daytime (LT) during these months. We performed theoretical modeling of electron density distribution for the cases when the G condition was registered, taking into account the correction of the neutral atmosphere model. The obtained calculations are in good agreement with observed data. Besides, we showed that variations in thermospheric parameters (density, composition, temperature, and wind velocity) can promote formation of the G condition under quiet geomagnetic conditions during the last extreme low solar activity.


      PubDate: 2015-06-20T13:39:38Z
       
  • Double core of ozone valley over the Tibetan Plateau and its possible
           mechanisms
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Dong Guo , Yucheng Su , Chunhua Shi , Jianjun Xu , Alfred M. Powell
      In this study, the three-dimensional structure of the ozone valley (e.g. ozone depletion) over the Tibetan Plateau (TP) in summer (June–August) has been investigated using Microwave Limb Sounder (MLS) ozone (O3) data from 2005 to 2013. A double core structure of the ozone valley over the TP is found with one depletion center in upper stratosphere (10–2hPa) named the upper core, and another depletion center, named the lower core, is observed in the upper troposphere/lower stratosphere (200–50hPa). The analysis indicates that the zonal deviation of ozone O3 * (O3 *=O3–[O3], here [O3] is the zonal mean of O3) at the upper core is nearly −1DU while its counterpart's deviation at the lower core is nearly –15DU. Large scale atmospheric circulation and terrain effects play an important role in the ozone valley at the lower core. In contrast, photochemistry reactions of odd chlorine including chlorine atoms (Cl) and chlorine monoxide (ClO) dominate the ozone valley at the upper core. Based on the MLS products, support for a chemical driver at the upper core is based on: (1) the significant diurnal variability of ozone suggests possible photochemistry reactions impacting the ozone valley; (2) the positive center of the ClO zonal deviation (CLO*) and hydrogen chloride (HCl) zonal deviation (HCl*) are found at the bottom of the upper core, which means the higher odd chlorine may accelerate the ozone loss.


      PubDate: 2015-06-20T13:39:38Z
       
  • First results of the high-resolution multibeam ULF wave experiment at the
           Ekaterinburg SuperDARN radar: Ionospheric signatures of coupled poloidal
           Alfvén and drift-compressional modes
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Pavel N. Mager , Oleg I. Berngardt , Dmitri Yu. Klimushkin , Nina A. Zolotukhina , Olga V. Mager
      A continuous experiment was carried out at the Ekaterinburg (EKB) stereoradar of the Russian segment of SuperDARN in order to examine the spatio-temporal characteristics of radar-detected magnetospheric ULF waves. The study of magnetospheric oscillations is based on analysis of scattering from field-aligned F-layer irregularities. Their E × B drift Doppler velocity at F-layer heights is associated with the background electric field in the ionosphere. During the experiment one of the radar channels operates in 0–2 beam scanning, with an integration time of 6s, which corresponds to the total 18-s time resolution at each beam. This allows detecting magnetospheric ULF waves with periods of 40s and up. Beam 0 is along the 132 magnetic meridian, so the registered velocity oscillations correspond to the wave electric field azimuthal component. Operation of the radar in this mode was started in December 2013. The first ULF wave events observed in the experiment and presented here occurred on 14 December 2013 and 2 January 2014 in the nightside magnetosphere during two geomagnetic disturbances classified as small magnetic storms and associated with high speed streams from coronal holes. Both the ULF events occurred after substorm-like auroral disturbances. The ULF waves observed during these events are classified as Pc5 geomagnetic pulsations. Two oscillation branches were observed, the higher and the lower frequency ones. As the azimuthal wave numbers m increase, the branches converge and merge into a single oscillation branch at some critical azimuthal wave number value m ⋆ . This ω ( m ) dependence is characteristic of the coupled Alfvén and drift-compressional waves which according to theory merge if the azimuthal wave number exceeds some critical value. This merged single oscillation branch represents an unstable drift ballooning coupling mode. Thus, the following interpretation of the observed events can be suggested; at m < m ⋆ the higher and lower frequency branches can be identified with the Alfvén and drift-compressional modes, respectively, and at m > m ⋆ the single branch can be identified with the drift ballooning coupling mode.


      PubDate: 2015-06-20T13:39:38Z
       
  • Night-time light ion transition height behaviour over the Kharkiv
           (50°N, 36°E) IS radar during the equinoxes of 2006–2010
    • Abstract: Publication date: September 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 132
      Author(s): Dmytro V. Kotov , Vladimír Truhlík , Phil G. Richards , Stanimir Stankov , Oleksandr V. Bogomaz , Leonid F. Chernogor , Igor F. Domnin
      This research investigates anomalous nighttime ion density behaviour over the Kharkiv, Ukraine incoherent scatter radar (49.6° N, 36.3° E, 45.3° inv) during the equinoxes of 2006–2010. The observations show that the altitude of the transition from O+ to lighter ions was much lower than empirical and physical models predict. The standard physical model produces very good agreement for the O+ densities but underestimates the H+ densities by a factor of 2 in March 2006 and a factor of 3 in March 2009. The anomalously low transition height is a result of similar lowering of the ionospheric peak height and also of significantly increased H+ density. The lower ionospheric peak height may be caused by weaker nighttime neutral winds. The calculations indicate that the higher measured topside ionosphere H+ densities are most likely due to higher neutral hydrogen densities. Both factors could be the result of weaker than usual magnetic activity, which would reduce the energy input to high latitudes. Prolonged low activity periods could cause a global redistribution of hydrogen and also allow more neutral hydrogen to settle down from the exosphere into the mid-latitude ionosphere. The finding of the need for higher H densities agrees well with recent H-alpha airglow measurements and it is important for accurate modelling of plasmasphere refilling rates and night-time N m F 2 values.


      PubDate: 2015-06-20T13:39:38Z
       
  • Statistical investigation of the noise added to a model of the effect of
           solar activities on the plasma of the ionosphere using DEMETER satellite
           data
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Mahmoud Sharzehei , M.A. Masnadi-Shirazi , Sh. Golbahar-Haghighi
      Although a relation between ionospheric anomalies and occurrence of strong earthquake has been studied for several decades, the issue of finding anomalies in ionospheric parameter before earthquakes has been always a matter of controversy among scientific community. In this way, the study of the ionosphere by satellite observers plays a significant role in assessing the feasibility of finding anomalies in ionospheric parameters as short-term precursors of earthquakes. Regardless of whether this assertion about ionospheric precursor is true or false, the ionosphere has been shown to be affected more by solar activities than other events such as seismic activities; thus, the modeling of ionospheric variation caused by solar activities is valuable in assessing the possibility of ionospheric precursors. One of the most famous satellites launched to investigate the ionospheric plasma perturbation associated with solar and seismic activities is the DEMETER, the French micro-satellite. To carry on such investigation, one of its payloads, the onboard IAP experiment, allows for the measurement of important plasma parameters including ion composition densities and their temperature. The current work presents a statistical distribution for the noise added to the proposed model describing the regular effect of solar activities on the ionospheric plasma above Iran during one half-orbit time of the DEMETER (~35min) in the absence of an earthquake and a quiet time condition. The results of this study show that the proposed modeling noise statistically agrees with the Gaussian distribution; however, its variance may vary from one day to another. In other words, the noise is a non-stationary random process. The proposed model is then evaluated by a set of experimental data. The results of this evaluation show that the measured data follow the proposed model.


      PubDate: 2015-06-20T13:39:38Z
       
  • Aerosol optical properties over a coastal site in Goa, along the west
           coast of India.
    • Abstract: Publication date: August 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volumes 130–131
      Author(s): Shilpa Shirodkar , Harilal B. Menon
      Spectral characteristics of the Aerosol optical depths (AODs) measured over a coastal site in Goa (15.46°N and 73.83°E), from a plateau ~50m above mean sea level, for the period 2008–2010, are analyzed to understand the inter-seasonal and intra-seasonal variability and to delineate different aerosol sources. A Microtops-II sunphotometer having five different wavelengths centered at 0.380, 0.440, 0.500, 0.675 and 0.870µm was used to estimate AODs in different seasons classified as: winter monsoon season from December to March (WMS), spring inter-monsoon season from April to May (SIMS), summer monsoon season from June to September (SMS) and fall inter-monsoon season from October to November (FIMS). The number of data (AODs) generated in each season is 569 in WMS, 131 in SIMS, 38 in SMS and 256 in FIMS. The highest AOD at 500nm (AOD500) was recorded in SIMS (0.43±0.18) while the lowest value was observed in SMS (0.32±0.10). The seasonal mean values of Ångström α computed from the least-square method in the wavelength range 0.440–0.870μm showed higher values (1.23±0.20) in FIMS than those in SMS (0.75±0.34). The highest Ångström β values were noticed in SIMS (0.25±0.10) and lowest in FIMS (0.17±0.06). To make a source appropriation and thus to resolve the complexity of aerosols in the study area, α was computed in different wavelength ranges, viz: short wavelengths (0.440–0.500μm) and long wavelengths (0.675–0.870μm), which revealed differing α values for different ranges of wavelengths. To account for the curvature, a second order polynomial fit is introduced. Subsequently, the second-order Ångström exponent (ά) and the coefficient of the second-order polynomial fit are analyzed to understand the dominant aerosol type.
      Graphical abstract image

      PubDate: 2015-06-20T13:39:38Z
       
  • IFC-Ed. board
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129




      PubDate: 2015-06-20T13:39:38Z
       
  • Long-delayed bright dancing sprite with large Horizontal displacement from
           its parent flash
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Jing Yang , Gaopeng Lu , Li-Jou Lee , Guili Feng
      We reported in this paper the observation of a very bright long-delayed dancing sprite with distinct horizontal displacement from its parent stroke. The dancing sprite lasted only 60ms, and the morphology consisted of three fields with two slim dim sprite elements in the first two fields and a very bright large element in the third field, different from other observations where the dancing sprites usually contained multiple elements over a longer time interval, and the sprite shape and brightness in the video field are often similar to the previous fields. The bright sprite was displaced at least 38km from its parent cloud-to-ground (CG) stroke and occurred over comparatively higher cloud top region. The parent flash of this compact dancing sprite was of positive polarity, with only one return stroke (approximately +24kA) and obvious continuing current process, and the charge moment change of stroke was small (barely above the threshold for sprite production). All the sprite elements occurred during the continuing current stage, and the bright long-delayed sprite element induced a considerable current pulse. The dancing feature of this sprite may be linked to the electrical charge structure, dynamics and microphysics of parent storm, and the inferred development of parent CG flash was consistent with previous very high-frequency (VHF) observations of lightning in the same region.


      PubDate: 2015-06-20T13:39:38Z
       
  • Extracting planetary waves from geomagnetic time series using Empirical
           Mode Decomposition
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Dennis Frühauff , Karl-Heinz Glassmeier , Michael Lockwood , Daniel Heyner
      Empirical Mode Decomposition is presented as an alternative to traditional analysis methods to decompose geomagnetic time series into spectral components. Important comments on the algorithm and its variations will be given. Using this technique, planetary wave modes of 5-, 10-, and 16-day mean periods can be extracted from magnetic field components of three different stations in Germany. In a second step, the amplitude modulation functions of these wave modes can be shown to contain significant contribution from solar cycle variation through correlation with smoothed sunspot numbers. Additionally, the data indicate connections with geomagnetic jerk occurrences, supported by a second set of data providing reconstructed near-Earth magnetic field for 150 years. Usually attributed to internal dynamo processes within the Earth's outer core, the question of who is impacting whom will be briefly discussed here.


      PubDate: 2015-06-20T13:39:38Z
       
  • An improved technique for global solar radiation estimation using
           numerical weather prediction
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): M.A. Shamim , R. Remesan , M. Bray , D. Han
      Global solar radiation is the driving force in hydrological cycle especially for evapotranspiration (ET) and is quite infrequently measured. This has led to the reliance on indirect techniques of estimation for data scarce regions. This study presents an improved technique that uses information from a numerical weather prediction (NWP) model (National Centre for Atmospheric Research NCAR's Mesoscale Meteorological model version 5 MM5), for the determination of a cloud cover index (CI), a major factor in the attenuation of the incident solar radiation. The cloud cover index (CI) together with the atmospheric transmission factor (K T ) and output from a global clear sky solar radiation were then used for the estimation of global solar radiation for the Brue catchment located in the southwest of England. The results clearly show an improvement in the estimated global solar radiation in comparison to the prevailing approaches.


      PubDate: 2015-06-20T13:39:38Z
       
  • A method to measure the broadband longwave irradiance in the terrestrial
           direct solar beam
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Ibrahim Reda , Jörgen Konings , Yu Xie
      Shortwave radiometers such as pyranometers, pyrheliometers, photovoltaic cells, and longwave radiometers such as pyrgeometers are calibrated with traceability to consensus References, which are maintained by Absolute Cavity Radiometers (ACRs) and the World InfraRed Standard Group (WISG), respectively. Since the ACR is an open cavity with no window, and was developed to measure the extended broadband spectrum of the terrestrial direct solar beam irradiance, then there would be discrepancy in calibrating the shortwave radiometers because of their limited spectral band. On the other hand, pyrgeometers are calibrated during the nighttime only, because no consensus reference has yet been established for the daytime longwave irradiance. This article describes a method to measure the broadband longwave irradiance in the terrestrial direct solar beam from 3µm to 50µm. The method might be used in developing calibration methods to address the mismatch between the broadband ACR and shortwave radiometers, and the lack of a daytime reference for pyrgeometer calibration. We used the described method to measure the irradiance from sunrise to sunset; the irradiance varied from approximately 1Wm−2 to 16Wm−2 with an estimated uncertainty of 1.46Wm−2, for a solar zenith angle range from 80° to 16°, respectively.


      PubDate: 2015-06-20T13:39:38Z
       
  • Ionosphere equatorial ionization anomaly observed by GPS radio
           occultations during 2006–2014
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Xinan Yue , William S. Schreiner , Ying-Hwa Kuo , Jiuhou Lei
      A large number of Global Position System (GPS) radio occultation (RO) observations have been accumulated in the University Corporation for Atmospheric Research (UCAR) Constellation Observation System for Meteorology, Ionosphere and Climate (COSMIC) Data Analysis and Archive Center (CDAAC) especially since the launch of COSMIC mission. This study made use of these RO data to study the morphology of ionosphere equatorial ionization anomaly (EIA) statistically during 2006–2014. The ionospheric peak density (NmF2) and peak height (hmF2) derived from the RO electron density profiles as well as the derived magnetic latitude of both crests and trough, the trough width, and the crest-to-trough ratio (CTR) of NmF2 are analyzed systematically. The corresponding seasonal, local time, and solar activity variations and the hemispheric asymmetry are identified and discussed. Most morphology agree well with previous studies and could be explained by the corresponding variations of neutral wind/composition and ExB vertical drift. We also found some interesting features. During May–August, magnetic latitude of the trough could be up to ~5° north of the equator especially around noontime, and the local time difference corresponding best developed EIA between both hemispheres could be up to ~6h. Both crests even move equator-ward with the increase of solar activity in the morning sector except June solstice.


      PubDate: 2015-06-20T13:39:38Z
       
  • Automatic scaling of the sporadic E layer and removal of its multiple
           reflection and backscatter echoes for vertical incidence ionograms
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Chunhua Jiang , Yuannong Zhang , Guobin Yang , Peng Zhu , Hengqing Sun , Xiao Cui , Huan Song , Zhengyu Zhao
      This paper presents a method for automatically scaling the sporadic E (Es) layer and removing its multiple reflection and backscatter echoes for vertical incidence (VI) ionograms. First, the method scales the Es layer automatically. Then, it removes the traces of multiple reflection and backscatter of the Es layer to clean VI ionograms using the parameters of the Es layer. Ionograms recorded at Wuhan (30.5°N, 114.37°E) are used to verify the performance of the proposed method compared with manually scaled values. The results indicate that the proposed method can automatically scale the Es layer and effectively improve the performance of the technique developed by Jiang et al. (2013).


      PubDate: 2015-06-20T13:39:38Z
       
  • Short term change in relative humidity during the festival of Diwali in
           India
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Nandita D. Ganguly
      The changes in humidity levels during the Diwali festivities have been examined over a period of 13 years at three Indian metro cities: Ahmedabad, New Delhi and Kolkata. A small short term increase in relative humidity even in the absence of transport of humid air from Arabian Sea and Bay of Bengal has been observed. The relative humidity levels were found to be exceeding the ambient levels during night and lying below the ambient levels during morning hours, indicating an increase in the survival rates of viruses responsible for the transmission of viral infections, as well as triggering immune-mediated illnesses such as asthma during Diwali.


      PubDate: 2015-06-20T13:39:38Z
       
  • Ionospheric anomalous disturbance during the tropospheric strong
           convective weather
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Zhongya Cang , Guangguang Cheng , Guosheng Cheng
      Based on TBB data from Chinese FY-2 geostationary satellite, NCEP Reanalysis data and GPS-TEC data provided by IGS, by using sliding mean method, ionospheric anomalous disturbance during a typical convective weather was investigated. Results show that this severe convective weather was caused by a high-altitude cold eddy and a strong squall line. The ionospheric total electron content increased abnormally when convection occurred. The maximum increase of tested point was more than 6TECU mainly at 8–12 UT of the day, and the peak time of the day lagged about 2h than usual. Ionospheric anomalous region reached about 20 longitudes and 10 latitudes, and anomalous center was on the west side of the convective cloud, which may be related to the topographic effect of the Tibetan Plateau. Series of Case Studies further determine that convective weather can influence the ionospheric state. Furthermore, tropospheric vertical velocity was also analyzed to discuss the possible mechanisms of troposphere–ionosphere coupling.


      PubDate: 2015-06-20T13:39:38Z
       
  • Effect of diurnal variation of aerosols on surface reaching solar
           radiation
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Kishore Reddy , D.V. Phanikumar , Hema Joshi , Y. Nazeer Ahammed , M. Naja
      In this report, we attempt to quantify direct aerosol radiative forcing by considering the diurnal variation of aerosols over central Himalayan region. The measured day time aerosol optical depth (AOD) values are higher by a small magnitude ≤15% during forenoon and reached as high as 90% by late afternoon when compare to night time AOD. The above observation gives clue about transport of regional polluted aerosols to the observational site. Our results show, 10 (16) % increment in atmospheric radiative forcing due to diurnal variation of aerosols instead of average aerosols during winter (post-monsoon) season.


      PubDate: 2015-06-20T13:39:38Z
       
  • Assessment of errors in Precipitable Water data derived from Global
           Navigation Satellite System observations
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Pawel Hordyniec , Jaroslaw Bosy , Witold Rohm
      Among the new remote sensing techniques, one of the most promising is a GNSS meteorology, which provides continuous remote monitoring of the troposphere water vapor in all weather conditions with high temporal and spatial resolution. The Continuously Operating Reference Station (CORS) network and available meteorological instrumentation and models were scrutinized (we based our analysis on ASG-EUPOS network in Poland) as a troposphere water vapor retrieval system. This paper shows rigorous mathematical derivation of Precipitable Water errors based on uncertainties propagation method using all available data source quality measures (meteorological sensors and models precisions, ZTD estimation error, interpolation discrepancies, and ZWD to PW conversion inaccuracies). We analyze both random and systematic errors introduced by indirect measurements and interpolation procedures, hence estimate the PW system integrity capabilities. The results for PW show that the systematic errors can be under half-millimeter level as long as pressure and temperature are measured at the observation site. In other case, i.e. no direct observations, numerical weather model fields (we used in this study Coupled Ocean Atmospheric Mesoscale Prediction System) serves as the most accurate source of data. Investigated empirical pressure and temperature models, such as GPT2, GPT, UNB3m and Berg introduced into WV retrieval system, combined bias and random errors exceeding PW standard level of accuracy (3mm according to E-GVAP report). We also found that the pressure interpolation procedure is introducing over 0.5hPa bias and 1hPa standard deviation into the system (important in Zenith Total Delay reduction) and hence has negative impact on the WV estimation quality.


      PubDate: 2015-06-20T13:39:38Z
       
  • Time evolution of ionization effect due to cosmic rays in terrestrial
           atmosphere during GLE 70
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): A.L. Mishev , P.I.Y. Velinov
      In the last years the possible effect of solar variability on atmospheric physics and chemistry is highly debated. In most of the proposed models the role of ion production in the atmosphere due to cosmic rays is significant. At present, effects on minor constituents and aerosols are observed over polar regions during major solar events. According to recent findings for such a study it is necessary an essential increase of ion production, specifically during the winter season. Therefore, the ground level enhancement on 13th of December 2006 is appropriate for such a study. Here, we compute the ion production on 13th of December 2006 on the basis of a full target model based on Monte Carlo simulations. The ion production is computed on a step ranging from 10 to 30min throughout the event. The spectral and angular characteristics of the solar protons are explicitly considered as well as their time evolution. The ionization effect is computed at several altitudes above the sea level, namely 25km, 18km, 15km, 12km and 8km in a sub-polar a and polar region, where the effect is maximal. Several applications of the obtained results are discussed.


      PubDate: 2015-06-20T13:39:38Z
       
  • An analysis of selected aspects of irregularities oval monitoring using
           GNSS observations
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): R. Sieradzki
      The increasing number of permanent GNSS (Global Navigation Satellite System) receivers allows for more extensive ionospheric studies, involving the monitoring of the irregularities oval at high northern latitudes. Due to the high dynamics of the circumpolar ionosphere, the investigations aimed at a comprehensive view of oval should be carried out with as short a time resolution as possible. The shortening of this time interval leads to irregular coverage of the ionosphere by GNSS observations and has to be preceded by the preliminary analysis of selected aspects. Two of them are presented in this paper. The first one is the dependence of measured total electron content (TEC) fluctuations on the elevation angle of satellite observations. The results related to this point show its strong influence, clearly visible at low and high elevation angles. Furthermore, the additional impact of geomagnetic azimuth has been detected at lower elevation angles. The second analysed aspect is the comparative analysis of TEC fluctuation level changes observed in universal time and magnetic local time domains. Generally the study has confirmed the occurrence of oval variations, which can be monitored using subdaily maps of TEC fluctuations. The higher dynamics of ionospheric conditions have been observed in universal time domain, especially during the disturbed time. It indicates that the interpolation of TEC fluctuations values for regions without real data is more appropriate in magnetic local time domain.


      PubDate: 2015-06-20T13:39:38Z
       
  • Effect of recent minor volcanic eruptions on temperatures in the upper
           troposphere and lower stratosphere
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Sanjay Kumar Mehta , Masatomo Fujiwara , Toshitaka Tsuda , Jean-Paul Vernier
      The impact of the recent minor volcanic eruptions during 2001–2010 in the temperature of the upper troposphere and lower stratosphere (UTLS) is investigated using data from the Global Positioning System Radio Occultation (GPS RO), three radiosonde compilations and two reanalyses (ERA-Interim and MERRA). The volcanic signals are identified in the residual temperature time series after removal of the linear trend, the quasi-biennial oscillation and El Nino Southern Oscillation components. Eight minor volcanic eruptions (six from the tropics and two from midlatitude) over the last decade (2001–2010) are analyzed in this study. We found significant volcanic signals in the UTLS temperature only in association with the tropical Soufrière Hills and Tavurvur eruptions (in May 2006 and in October 2006, respectively). Other four tropical eruptions had very small aerosol perturbations and did not show any significant UTLS temperature change. Out of the two midlatitude eruptions, Sarychev peak had similar stratospheric aerosol perturbations as Soufrière Hills and Tavurvur eruptions, but did not show any significant UTLS temperature change. The volcanic signals in the UTLS temperature from the tropical Soufrière Hills and Tavurvur eruptions were observed for the period of 7 months after August 2006. A warming of 0.5–0.8K in the tropical 16–18.5km (100–70hPa) layer was observed in association with these two tropical eruptions.


      PubDate: 2015-06-20T13:39:38Z
       
  • F region electron density profile inversion from backscatter ionogram
           based on international reference ionosphere
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Peng Zhu , Chen Zhou , Yuannong Zhang , Guobin Yang , Chunhua Jiang , Hengqing Sun , Xiao Cui
      Ionospheric backscatter sounding transmits HF (3–30MHz) radio wave obliquely into ionosphere and receives echoes backscattered from remote ground. Due to the focusing effect, the echoes form leading edge on the swept frequency backscatter ionogram (BSI). This kind of backscatter ionogram contains plentiful ionospheric information, such as electron density, radio wave propagation modes and maximum usage frequency (MUF). By inversion algorithm, the backscatter ionogram can provide two-dimensional electron density profile (EDP) down range. In this paper, we propose an ionospheric F2 region EDP inversion algorithm. By utilizing the F2 bottomside electron density profile represented by the International Reference Ionosphere (IRI) model and ray tracing techniques, this approach inverts the leading edge of the backscatter ionogram to two dimensional F region EDP. Results of validation experiments demonstrate that the inverted ionospheric EDPs show good agreement with the results of vertical ionosonde and provide reliable information of ionosphere. Thus the proposed inversion algorithm provide an effective and accurate method for achieving large scale and remote ionospheric electron density structure.


      PubDate: 2015-06-20T13:39:38Z
       
  • Observations of large-amplitude electromagnetic waves and associated
           wave–particle interactions at the dipolarization front in the
           Earth's magnetotail: A case study
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): S.Y. Huang , Z.G. Yuan , B. Ni , M. Zhou , H.S. Fu , S. Fu , X.H. Deng , Y. Pang , H.M. Li , D.D. Wang , H.M. Li , X.D. Yu
      Broadband frequency waves around the dipolarization front (DF) are believed to play a crucial role in the particle dynamics. Using the Cluster observations, we report in this study large-amplitude electromagnetic waves with frequencies just above the ion cyclotron frequency at the DF in the near-Earth magnetotail region. The waves have very large amplitudes of magnetic and electric field fluctuations, up to ~2nT and ~10mV/m, respectively. The magnetic fluctuations are predominately along the ambient magnetic field (B 0 ), while the electric fluctuations are primarily perpendicular to B 0 . The observed waves are highly oblique with a propagation angle of ~100° with respect to the ambient magnetic field, and are also linearly polarized. These features are consistent with the properties of the ion Bernstein wave mode in the high plasma β region, and also with the properties of current-driven ion cyclotron waves driven by the electromagnetic current-driven Alfven instability. We also discuss the possibility of wave–particle interactions at the DF.


      PubDate: 2015-06-20T13:39:38Z
       
  • Dynamically induced hemispheric differences in the seasonal cycle of the
           summer polar mesopause
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): Erich Becker , Rahel Knöpfel , Franz-Josef Lübken
      A mechanistic atmospheric general circulation model from the surface up to the mesopause region with explicit representations of radiation and the tropospheric moisture cycle is employed to study hemispheric differences during the summer season with focus on dynamical coupling processes in the middle atmosphere. Hemispheric differences are imposed in the model by the geographical distributions of surface parameters. Consistent with reanalyses, we find that prior to summer solstice, the polar troposphere and lower stratosphere are significantly colder in the southern hemisphere than in the northern hemisphere. This induces vertically altering wind and temperature differences between the two hemispheres that are consistent with the recently detected Intrahemispheric Coupling mechanism. In particular, in the southern hemisphere the model yields a high mesopause around solstice which propagates downward over the season. Such a behavior has recently been observed by lidar measurements in Antarctica and is different from the northern hemisphere where the polar mesopause stays at approximately the same altitude over the summer season. After summer solstice, the mesopause is significantly warmer in the southern hemisphere, which is in accordance with Interhemispheric Coupling, i.e., the hemispheric differences after summer solstice are influenced by the strong planetary Rossby-wave activity in the northern stratosphere during boreal winter. Also enhanced filtering of eastward GWs in the southern troposphere contributes to the behavior after solstice. Orbital eccentricity is found to enhance the importance of Intrahemispheric Coupling. A more quantitative description of the hemispheric differences in the stratosphere and lower mesosphere as seen in reanalyses is obtained by adding an additional westward gravity drag in the southern stratosphere. The vertical coupling mechanisms responsible for hemispheric differences apply also in this case.


      PubDate: 2015-06-20T13:39:38Z
       
  • Study of surface ozone at Port Blair, India, a remote marine station in
           the Bay of Bengal
    • Abstract: Publication date: July 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics, Volume 129
      Author(s): T.K. Mandal , S.K. Peshin , C. Sharma , Prabhat Kumar Gupta , Rachit Raj , S.K. Sharma
      This paper presents seasonal variation of surface ozone monitored continuously at site of the meteorological observatory at Port Blair, a maritime site of the Bay of Bengal for the period of August, 2005–March, 2007. Present observation depicts the characteristics of surface ozone at the remote marine site and the long range transport of pollutants from three different sides i.e., Indian Subcontinent, South East Asia and Indian Ocean. Very high ozone mixing ratio (~70–80ppbv) is occasionally observed during March and November at this site. A campaign mode of observation of trace gases (surface ozone, CO, NO x , CO2), aerosol concentration and its size, UV radiation at Port Blair was made to understand the role of transport on pollutants during March 16–26, 2002. During this period of observation, a near zero surface ozone of different time scales (~few hours) has been observed several times during the period of midnight to early morning. Simultaneously NO x (NO+NO2) (~40ppbv) and carbon monoxide was observed very high (300–600ppbv) during this period. Source of this high pollutant are not expected at this remote marine sites although wind patterns, 7-days isentropic back Trajectory analysis and MATCH Model output suggest that polluted air mass has come from eastern side of Indian subcontinent.


      PubDate: 2015-06-20T13:39:38Z
       
  • Coherent structures in the Es layer and neutral middle atmosphere
    • Abstract: Publication date: Available online 17 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Zbyšek Mošna , Petra Koucká Knížová , Kateřina Potužníková
      The present paper shows results from the summer campaign performed during geomagnetically quiet period from June 1 to August 31, 2009. Within time–series of stratospheric and mesospheric temperatures at pressure levels 10hPa to 0.1hPa, mesospheric winds measured in Collm, Germany, and the sporadic E–layer parameters foEs and hEs measured at the Pruhonice station we detected specific coherent wave–bursts in planetary wave domain. Permanent wave–like activity is observed in all analyzed data sets. However, number of wave–like structures persistent in large range of height from the stratosphere to lower ionosphere is limited. The only coherent modes that are detected on consequent levels of the atmosphere are those corresponding to eigenmodes of planetary waves.


      PubDate: 2015-06-20T13:39:38Z
       
  • A comparison of stratospheric photochemical response to different
           reconstructions of solar ultraviolet radiative variability
    • Abstract: Publication date: Available online 15 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Cassandra Bolduc , Michel S. Bourqui , Paul Charbonneau
      We present calculations of stratospheric chemical abundances variations between different levels of solar activity using a simple photochemistry model in transient chemistry mode. Different models for the reconstruction of the solar spectrum, as well as observations from the SOLar STellar Irradiance Comparison Experiment (SOLSTICE) and Spectral Irradiance Monitor (SIM) on the SOlar Radiation and Climate Experiment (SORCE) satellite, are used as inputs to the calculations. We put the emphasis on the MOnte CArlo Spectral Solar Irradiance Model (MOCASSIM) reconstructions, which cover the spectral interval from 150 to 400nm and extend from 1610 to present. We compare our results with those obtained with the Naval Research Laboratory Solar Spectral Irradiance (NRLSSI) model as well as with the Magnesium-Neutron Monitor (MGNM) model over a period of time spanning the ascending phase of Cycle 22. We also perform the calculations using SORCE composite spectra for the descending phase of Cycle 23 and with the reconstructed MOCASSIM, NRLSSI and MGNM spectra for the same period for comparison. Finally, we compare the chemical abundances obtained for the Maunder Minimum with those obtained for the Cycle 23 minimum (in March 2009) and find that stratospheric ozone concentration was slightly higher during the recent minimum, consequent to the small positive variability between the MOCASSIM spectra for both epochs, especially below 260nm. We find that the response in stratospheric ozone is not only dependent on the variability amplitude in the solar spectrum (especially in the 200–240nm band), but also significantly on the base level of the minimum solar spectrum.


      PubDate: 2015-06-20T13:39:38Z
       
  • On the possible mechanism of keraunographic markings on lightning victims
    • Abstract: Publication date: Available online 15 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Vernon Cooray , Gerald Cooray , Charith Cooray
      During a lightning strike to a human the high electric field that exists at the point of contact of the lightning flash can generate electrical discharges known as streamer discharges along the skin. Previous research work has shown that the electric field at the head of these streamer discharges are large enough to accelerate electrons to relativistic speeds. In this paper it is shown that the streamers propagating along the skin will bombard the skin with energetic electrons. In this paper an estimation of the energy dissipated by these energetic electrons on the skin is estimated. Since beta radiation generated by radioactive substances consists of energetic electrons the effects of the energetic electrons generated by streamer discharges would be similar to the effects caused by low level beta radiation. It is suggested that the feather like marks, called keraunographical marks, that is sometimes observed on the skin of lightning victims is a result of superficial radiation injury with following inflammation in the epidermis and superficial layers of the dermis caused by energetic electrons.


      PubDate: 2015-06-20T13:39:38Z
       
  • Optical emission and peak electromagnetic power radiated by negative
           return strokes in rocket-triggered lightning
    • Abstract: Publication date: Available online 11 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Mason G Quick , E. Philip Krider
      Calibrated measurements of the optical radiation produced by negative return strokes in rocket-triggered lightning (RTL) have been made in the visible and near infrared (VNIR) spectral region in correlation with currents measured at the channel base. Using a simple transmission-line model, the currents have been used to estimate the peak electromagnetic (EM) fields and Poynting power that are radiated in the time-domain (i.e. from about 1kHz to 3MHz). The results show that the optical power radiated by RTL at the time of the peak current has a mean and standard deviation of 130±120MW, a value that is only about 5% of the Poynting power that is radiated into the upper half-space at that time. These results are in good agreement with similar measurements made on the subsequent return strokes in natural lightning that remain in a pre-existing channel. Our methods and assumptions are similar to those of (Guo and Krider, 1983; Krider and Guo, 1983; Quick and Krider, 2013).


      PubDate: 2015-06-20T13:39:38Z
       
  • High-altitude electrical discharges associated with thunderstorms and
           lightning
    • Abstract: Publication date: Available online 10 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Ningyu Liu , Matthew G. McHarg , Hans C. Stenbaek-Nielsen
      The purpose of this paper is to introduce electrical discharge phenomena known as transient luminous events above thunderstorms to the lightning protection community. Transient luminous events include the upward electrical discharges from thunderstorms known as starters, jets, and gigantic jets, and electrical discharges initiated in the lower ionosphere such as sprites, halos, and elves. We give an overview of these phenomena with a focus on starters, jets, gigantic jets, and sprites, because similar to ordinary lightning, streamers and leaders are basic components of these four types of transient luminous events. We present a few recent observations to illustrate their main properties and briefly review the theories. The research in transient luminous events has not only advanced our understanding of the effects of thunderstorms and lightning in the middle and upper atmosphere but also improved our knowledge of basic electrical discharge processes critical for sparks and lightning.


      PubDate: 2015-06-20T13:39:38Z
       
  • Winter-time dependence of the global TEC on the stratospheric temperature
           and solar radiation
    • Abstract: Publication date: Available online 9 June 2015
      Source:Journal of Atmospheric and Solar-Terrestrial Physics
      Author(s): Plamen Mukhtarov , Dora Pancheva
      This paper presents a simple linear regression model that enables to quantify the contribution of high-latitude stratospheric temperature and solar radiation (describes by its proxy F10.7) to the variability of the low-latitude TEC during winter. The model is based on cross-correlation analysis performed on the Aura MLS temperature measurements and the global CODE TEC data for the period of time 2005–2010, i.e. at low to moderate solar activity (F10.7 changes between~65 and ~140 solar flux units). It revealed that the temperature at altitude of ~40km and latitude of ~60°N describes the most typical winter conditions and shows the largest negative correlation with the low-latitude TEC. This temperature namely is included in the regression model. The model results have been compared with the TEC data by calculating the standard deviation (STD). The comparison indicated that the regression model describes almost half of the real variability of the global TEC and that the contribution of the temperature (that is only a part of forcing from below) is almost half of the solar variability (i.e. external forcing related to the photo-ionization). A possible mechanism for explaining the relationship between the high-latitude stratospheric increase of the temperature and low-latitude decrease of the TEC is suggested.


      PubDate: 2015-06-20T13:39:38Z
       
 
 
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