Journal of Atmospheric and Solar-Terrestrial Physics最新文献

{"title":"Estimation of adiabatic cooling and warming in the mesosphere and lower thermosphere","authors":"Jia Yue ,&nbsp;Ningchao Wang","doi":"10.1016/j.jastp.2025.106492","DOIUrl":"10.1016/j.jastp.2025.106492","url":null,"abstract":"<div><div>The adiabatic cooling and warming in the mesosphere and lower thermosphere (MLT) are estimated utilizing the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) measured CO₂ volume mixing ratio (VMR) vertical displacement from the global mean CO₂ VMR. This work confirms that the summer mesopause temperature is largely controlled by adiabatic cooling instead of any absorptive heating or chemical heating. The paper also reveals a previously overlooked layer of adiabatic warming in summer and adiabatic cooling in winter in the lower thermosphere, being driven by downwelling and upwelling associated with the winter-to-summer circulation. Since this adiabatic warming/cooling process is embedded in the thermosphere where the mean temperature rises sharply, it is not as distinct without removing the global mean temperature. The mesospheric temperature is the opposite, being lacking of strong heating sources. The heating anomaly (∼100 K) in the summer lower thermosphere is substantial. Because auroral heating also occurs in the geomagnetic polar lower thermosphere, the interaction between the adiabatic warming/cooling in the lower thermosphere and auroral heating should be considered in future studies.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106492"},"PeriodicalIF":1.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Five-years altitude statistics of noctilucent clouds based on multi-site wide-field camera survey","authors":"Oleg S. Ugolnikov ,&nbsp;Nikolay N. Pertsev ,&nbsp;Vladimir I. Perminov ,&nbsp;Ilya S. Yankovsky ,&nbsp;Dmitry N. Aleshin ,&nbsp;Ekaterina N. Tipikina ,&nbsp;Alexander A. Ilyukhin ,&nbsp;Egor O. Ugolnikov ,&nbsp;Stanislav A. Korotkiy ,&nbsp;Olga Yu. Golubeva ,&nbsp;Andrey M. Tatarnikov ,&nbsp;Sergey G. Zheltoukhov ,&nbsp;Alexey V. Popov ,&nbsp;Alexey S. Sushkov ,&nbsp;Egor A. Volkov ,&nbsp;Natalya S. Krapkina ,&nbsp;Damir I. Yalyshev","doi":"10.1016/j.jastp.2025.106491","DOIUrl":"10.1016/j.jastp.2025.106491","url":null,"abstract":"<div><div>The results of simultaneous measurements of noctilucent clouds (NLC) position in a number of ground-based locations are presented. Observational data of 14 bright NLC events over 5 years is used for building the altitude maps of the cloud fields using the triangulation technique updated for multi-location case. The statistical distribution of NLC altitude and its change during the summer season is considered. Mean NLC altitudes are compared with estimations by colorimetric technique based on the same data and simple radiation transfer model. This can be used to check the model and estimate the accuracy of single-camera technique of NLC altitude measurements. Clouds appear in the altitude range from 79 to 84 km, the average height of NLC is found to be 81.4 km, while the mean brightness-weighted altitude is 0.5 km below this. The brightest clouds are observed near 80 km, where the ice particles can reach the maximal size. Possible effects of the increased height of NLC during the beginning of summer (June) and maximal solar activity (2024) are noted. Results and methods are suggested for the net ground-based survey of noctilucent clouds.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106491"},"PeriodicalIF":1.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is the variability of ENSO due to frequency modulation by the long term variation in solar activity?","authors":"Ian Edmonds ,&nbsp;Peter Killen","doi":"10.1016/j.jastp.2025.106490","DOIUrl":"10.1016/j.jastp.2025.106490","url":null,"abstract":"<div><div>The spectral content of the El Nino Southern Oscillation (ENSO) is broad and complex, a characteristic shared by other climate variables. Spectral analysis of ENSO in different time intervals demonstrated that ENSO is frequency modulated. An analytical model in which the natural period of ENSO is frequency modulated by long term centennial range variation in solar activity was developed and shown to correlate well with the observed ENSO and reconstructed ENSO variation in the decadal periodicity range. A method for identifying the occurrence and the period of frequency modulation in climate variables was developed and tested.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106490"},"PeriodicalIF":1.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Longitudinal responses of phase scintillation from ground stations during geomagnetic storms","authors":"Agegnehu Sisay ,&nbsp;Tsegaye Kassa","doi":"10.1016/j.jastp.2025.106452","DOIUrl":"10.1016/j.jastp.2025.106452","url":null,"abstract":"<div><div>This study analyzed the longitudinal variations of phase scintillation over United States (AB21 and AC66), Canada (UCLU, CAGS, ESCU, and STJO), Germany (HUEG and WTZZ), Ukraine (UZHL), Kazakhstan (KRTU), and Russia (BADG) sectors as the result of the intense geomagnetic storms of March 2015, June 2015, and December 2015 during solar cycle 24. Ground-based Global Positioning System (GPS) receivers, solar wind speed and magnetic (IMF Bz and Dst) data are used for this study. Total Electron Content (TEC) was used to derive the ionospheric phase scintillation/irregularities proxy indices, e.g., rate of change of TEC (ROT) and ROT index (ROTI).These indices were characterized alongside with the Disturbance Storm Time (Dst), Solar Wind Speed (Vsw), and Z component of Interplanetary Magnetic Field (IMF Bz) to see the effect of geomagnetic storm on horizontal component of geomagnetic field. Prompt Penetration of Electric Field (PPEF) modulated the behavior of irregularities during the initial and recovery phases of the geomagnetic storms (Demelash and Kassa, 2023). As a result, irregularities in the ionosphere over Canada, Germany, Ukraine, Kazakhstan, and Russia were found to range from weak to moderate in intensity. Regions in the United States, however, ranged between weak and strong. These phase scintillation generally occurred during the initial, main, and recovery phases of the storms at all selected stations. The effect of electric field was found to depend on the local time at which the IMF Bz turned into southward. The generation (inhibition) of phase scintillation is related to the effect of eastward (west-ward) storm time electric field disturbance dynamo electric fields and prompt penetration electric fields that created favorable (unfavorable) conditions for the generation of irregularities by uplifting (lowering) the F region. These findings highlight the presence of phase scintillation and fluctuations during different phases of geomagnetic storms, with varying intensities and durations across multiple locations.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106452"},"PeriodicalIF":1.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerosol Optical Properties and its radiative effects over two topographically different locations of the Indian Himalayan Region","authors":"Archana Bawari ,&nbsp;Jagdish Chandra Kuniyal ,&nbsp;Sheetal Chaudhary ,&nbsp;Renu Lata ,&nbsp;Bimal Pande","doi":"10.1016/j.jastp.2025.106487","DOIUrl":"10.1016/j.jastp.2025.106487","url":null,"abstract":"<div><div>This study investigates aerosol characteristics using ground-based measurements at two distinct regions, Mohal-Kullu (31.9°N, 77.12°E; 1154 m amsl) and Kosi-Katarmal (29.64°N, 79.62°E; 1225 m amsl), from July 2019 to June 2022. The average Black Carbon (BC) concentrations were 1.5 ± 1.0 μg m⁻³ at Mohal and 1.1 ± 1.4 μg m⁻³ at Katarmal. BC showed strong seasonal variability, with maxima during post-monsoon (2.6 ± 1.0 μg m⁻³) and pre-monsoon (1.8 ± 0.5 μg m⁻³) seasons. The diurnal variation displayed distinct morning and evening peaks in all the seasons. High pre-monsoon AOD₅₀₀ (0.30 ± 0.06 to 0.54 ± 0.08) and low values of Ångström exponent (0.67 ± 0.10 to 0.95 ± 0.30) indicated dominance of large particles, whereas lower AOD₅₀₀ (0.21 ± 0.07 to 0.25 ± 0.03) in post-monsoon and winter, along with larger Ångström exponent (1.05 ± 0.74 to 1.13 ± 0.11), indicated smaller particles. Satellite-derived (OMI and MAIAC) AOD₅₀₀ showed weak to moderate correlation with ground-based measurements at Mohal (R = 0.4639 for MAIAC, R = 0.1402 for OMI) and Katarmal (R = 0.3976 for MAIAC, R = 0.2980 for OMI). Using optical properties of aerosols and clouds (OPAC) and Santa Barbara discrete ordinate radiative transfer (SBDART) models, the short-wave aerosol radiative forcing (SWARF) was found negative at the surface and top of the atmosphere but positive in the atmosphere, suggesting significant surface cooling and atmospheric warming leading to high heating rates, respectively. Annual mean atmospheric radiative forcing was 27.36 ± 6.00 Wm⁻² at Mohal and 21.87 ± 7.26 Wm⁻² at Katarmal. These findings may have consequences for planning air pollution strategies and understanding the effects of regional climate change.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106487"},"PeriodicalIF":1.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of solar wind parameters on geomagnetic activity during the main phase of strong magnetic storms","authors":"R.N. Boroyev","doi":"10.1016/j.jastp.2025.106485","DOIUrl":"10.1016/j.jastp.2025.106485","url":null,"abstract":"<div><div>The relationship between the mean values of auroral activity indices and SW parameters during the periods of strong magnetic storms (|Dst_min| = 100 ± 10 nT) induced by SW different types is studied. 24 magnetic storms induced by (6) Sheath, (9) CIR, and (9) ICME events are selected for the period 1990–2020. It is shown that the against the background of the dependence of the auroral activity indices (AE, Kp and SME) on the SW electric field, the value of AE, Kp and SME indices is impacted by the IMF σВ. The geomagnetic indices increase with growth of the IMF σB magnitude. It is found that Sheath events have high geomagnetic index values in contrast to CIR and ICME. The SW type determines the relationship between geomagnetic indices and IMF σВ. The coefficient of correlation between IMF σB and Pd for Sheath (r = 0.65) has a close value with the correlation coefficients for the CIR and ICME events.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106485"},"PeriodicalIF":1.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A model to estimate energy deposition within the geomagnetosphere using Dst as a proxy for the Akasofu ϵ parameter","authors":"M.J. Birch","doi":"10.1016/j.jastp.2025.106480","DOIUrl":"10.1016/j.jastp.2025.106480","url":null,"abstract":"<div><div>This study compares the energy deposited into the geomagnetosphere by 14 co-rotating interaction regions (CIRs) and 14 interplanetary coronal mass ejections (ICMEs), selected from solar cycle 23, and covering a broad range of activity. The energy (<span><math><mi>E</mi></math></span>) is estimated using the Akasofu empirical coupling function and it was found that, on average, the ICMEs deposit about 15 times the energy contributed by the CIRs. The energy correlates very significantly with the peak (most negative) of the hourly <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>s</mi><mi>t</mi></mrow></msub></math></span> geomagnetic index observed during each event (first order fit, <span><math><mi>ρ</mi></math></span> = -0.94; second order fit, <span><math><mi>ρ</mi></math></span> = -0.97). Two modifications to the Akasofu relation proposed by de Lucas et al. are then incorporated into the energy calculations: the first replaces the radius of the effective area for the dayside magnetopause with a value which is a function of the solar wind ram pressure, and the second takes into account the dynamic pressure of the solar wind itself. As a result, <span><math><mi>ρ</mi></math></span> strengthens for the first order fit to -0.96, but weakens slightly for the second to -0.96, though all these correlations are highly significant. An empirical model is proposed of the form <span><math><mrow><mi>E</mi><mo>=</mo><mi>f</mi><mrow><mo>(</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>s</mi><mi>t</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span>, for which regression equations, correlation coefficients, standard errors and 1<span><math><mi>σ</mi></math></span> uncertainties are provided for both first and second order fits. The model provides an estimate of the energy deposited into the magnetosphere by solar particle events, using ground-based measurements, without recourse to in-situ measurements of the solar wind which are prone to data gaps during very energetic events.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"270 ","pages":"Article 106480"},"PeriodicalIF":1.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Total ozone content in southeastern South America: A statistical analysis of 45 years of satellite data","authors":"A. Laguarda ,&nbsp;M. Osorio","doi":"10.1016/j.jastp.2025.106468","DOIUrl":"10.1016/j.jastp.2025.106468","url":null,"abstract":"<div><div>This study investigates the Total Ozone Content (TOC) over Southeastern South America (SESA) using more than 45 years of satellite-derived data and ground-based Dobson spectrophotometer measurements over three sites. Satellite datasets from several missions were validated against ground-based Dobson observations, showing strong agreement with correlation coefficients exceeding 0.94 and biases below 2%. MERRA-2 monthly reanalysis data, also validated in this study, was used to complement satellite datasets for gap-filling. The analysis identified three distinct periods in ozone trends: a depletion phase (1979–1993) consistent with pre-Montreal Protocol conditions, a recovery phase (1994–2003) marked by positive trends, and a stabilization phase (2004–2023) with weak, less significant positive trends. Seasonal cycles during the stabilization period were obtained, showing lower ozone levels from January to May (around 265 DU), peaking in August to October (305 DU), with a consistent latitudinal gradient characterized by lower values at northern sites. A simple and accurate parametrization of the annual cycle was also derived at daily level, enabling daily ozone estimates and as a reference for anomaly detection. These findings contribute to a deeper understanding of ozone variability in the region, supporting global monitoring efforts and offering a foundation for evaluating the impacts of ozone dynamics on regional climate.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106468"},"PeriodicalIF":1.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microphysical characteristics of shallow precipitating systems in the southwest monsoon season: An analysis using in-situ and remote sensing observations","authors":"Anusha Andrews ,&nbsp;R.K. Sumesh ,&nbsp;E.A. Resmi ,&nbsp;Nita Sukumar ,&nbsp;Gadha Gopan ,&nbsp;Lekshmi Anilkumar ,&nbsp;Sumit Kumar ,&nbsp;M.G. Manoj ,&nbsp;Dharmadas Jash ,&nbsp;C.K. Unnikrishnan","doi":"10.1016/j.jastp.2025.106484","DOIUrl":"10.1016/j.jastp.2025.106484","url":null,"abstract":"<div><div>The present study examined the microphysical features of the shallow precipitating systems at low (10.04°N, 76.33°E, 20 m above MSL) and mid-altitude (8.45°N, 77.5°E; 400 m above MSL) locations situated on the windward side of the Western Ghats in southwest monsoon 2019. A total of 226 and 336 shallow precipitating systems were identified using radar reflectivity and surface rain rate from the co-located measurements using the micro rain radar and disdrometer instruments in both locations. The average cloud base height of shallow precipitating systems is ∼1 km. An elevated cloud layers (0.8–3.8 km) during long-duration shallow precipitating systems are more prevalent in low-altitude location. Shallow events in the mid-altitude region are characterized by long durations and high surface rain rates. Based on the duration and rain rates, the shallow systems are further classified for in-depth microphysical analysis. The broader raindrop size distribution spectra are clearly observed for the shallow events having higher duration and intensity. The concentration of small size raindrops are higher across all rain categories in the low-altitude location, while the concentration of mid-sized raindrops is notably higher in the heavy rain category indicating an active collision-coalescence process. Light rain events are predominantly characterized by small raindrops (D &lt; 1 mm), whereas moderate and heavy rainfall events are primarily composed of midsize raindrops (1 ≤ D &lt; 3 mm). The Nw-Dm relation for the shallow events in wet (dry) spells suggests that, isolated events mainly occur due to the local orographic effects of the elevated terrains.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106484"},"PeriodicalIF":1.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the finite transverse size of the accelerating region on the relativistic feedback","authors":"Alexander Sedelnikov ,&nbsp;Egor Stadnichuk ,&nbsp;Eduard Kim ,&nbsp;Oraz Anuaruly ,&nbsp;Daria Zemlianskaya","doi":"10.1016/j.jastp.2025.106475","DOIUrl":"10.1016/j.jastp.2025.106475","url":null,"abstract":"<div><div>Terrestrial gamma-ray flashes (TGFs) are commonly associated with relativistic runaway electron avalanches (RREAs). However, research shows that a single RREA cannot generate observable TGF fluxes. In an attempt to settle this issue the relativistic feedback mechanism was suggested by Joseph Dwyer. Finite transverse size of the accelerating region can affect feedback due to lateral diffusion of RREAs starting points. Electrons created by the feedback outside this region cannot be accelerated by the electric field and form an avalanche, which may lead to a decrease in the total number of new avalanches and an increase in the requirements for self-sustaining RREA production by the feedback. In this article the transverse propagation of avalanches starting points was described using a modified two-dimensional diffusion equation. A correction to the criterion for self-sustaining production of RREAs was obtained. Monte Carlo simulation was also performed to calculate the correction for the feedback coefficient.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"269 ","pages":"Article 106475"},"PeriodicalIF":1.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}