Journal of Atmospheric and Solar-Terrestrial Physics最新文献

{"title":"Vertical Profiles of Black Carbon and Associated Radiative Properties over India: Inter-comparison of Measured and Reanalysis Data","authors":"","doi":"10.1016/j.jastp.2024.106358","DOIUrl":"10.1016/j.jastp.2024.106358","url":null,"abstract":"<div><div>The significant uncertainties of Black Carbon (BC) radiative forcing are becoming an obstacle to the evaluation of their impacts and mitigation measures. One of the crucial reasons for this uncertainty could be the poorly constrained BC vertical profile. The BC has a lifetime of a few days to weeks and there is a clear pointer that it can be vertically transported through convection besides the horizontal advection. The present study aims for the intercomparison between the BC mass concentrations obtained through the aircraft-based observations and that derived from the selected Copernicus Atmosphere Monitoring Service (CAMS) reanalysis data over the three different locations of India, which is one of the largest emitters of BC aerosols. The aircraft-based BC observations were conducted from 0.5 to 7 km altitudes using Aethalometer during CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement Experiment) Phase I campaigns from June to September 2009. The output of the present study suggests the CAMS reanalysis data significantly underestimated BC mass throughout the vertical profile with an average mass normalized mean bias of greater than −70% at all three locations. Furthermore, the vertical radiative forcing and heating rates of BC were also calculated for both observation and reanalysis data. The output depicts the net forcing due to CAMS simulated BC in all the layers were 1–12 folds lower over all the study regions compared with observed BC aerosols. Likewise, the estimated mean biases in heating rate were in the range of −0.001 to −0.190 K day⁻¹ for all the vertical layers over the study locations. The possible reasons for these disparities could be poorly constrained emissions, especially aircraft emissions and/or their transformation schemes in aerosol modules. The present study emphasized that the validation of the vertical profile is also an essential factor for better constraints of the BC aerosols in climate models.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327102","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":"Analysis of the scintillation characteristics on the different satellite links derived from GPS observations and SCINDA data over Mbarara","authors":"","doi":"10.1016/j.jastp.2024.106353","DOIUrl":"10.1016/j.jastp.2024.106353","url":null,"abstract":"<div><div>Ionospheric scintillation is a frequent phenomenon over the low latitude regions. However, the severity of the scintillation on the various satellite-receiver links is a function of space and time. Therefore in satellite applications such as positioning, messages on satellite to ground links that are not affected by scintillation should be used. In this paper we present the statistics of scintillation on the accessible satellite links over Mbarara for the period 2011 to 2017. We used scintillation indices from the Scintillation Network Decision Aid (SCINDA) at Mbarara (Geographic coordinate -0.62°N, 30.66°E, and dip latitude -9.3°N) together with a proxy for amplitude scintillation derived from the carrier-to-noise ratio observable on the L1 frequency of the multi-frequency GPS receiver at Mbarara (Geographic coordinate -0.60°N, 30.74°E, and dip latitude -10.2°N) to characterise scintillation on different satellite links. The results showed that the proxy closely relate to amplitude scintillation index S4. Based on the proxy and the scintillation indices, both amplitude and phase scintillation over Mbarara peaks from 20:00–22:00 LT. Scintillation climatology shows equinoctial asymmetry with more frequent scintillation during autumnal equinox than vernal equinox. The spatial scintillation characteristics show that scintillation over Mbarara is directional with the most active regions in the azimuth range of <span><math><mo>∼</mo></math></span>150° to <span><math><mo>∼</mo></math></span>210°. The most affected links were for GPS satellites designated by the Pseudo Random Noise (PRN) number as PRN 31 and PRN 25 for amplitude and phase scintillation respectively, and the least affected by both phase and amplitude scintillation were PRN 5 and PRN 17. Based on these observations, we suggest that data from PRN 31 and PRN 25 be used with caution for satellite applications over Mbarara especially during times of scintillation.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357582","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":"The influence of the solar wind electric and magnetic fields on the latitude and temporal variations of the current density, JZ, of the global electric circuit, with relevance to weather and climate","authors":"","doi":"10.1016/j.jastp.2024.106355","DOIUrl":"10.1016/j.jastp.2024.106355","url":null,"abstract":"<div><div>Observations have shown small day-to-day stratiform cloud opacity and atmospheric dynamical responses to variations in the ionosphere-earth current density (<em>J</em>_<em>Z</em><em>).</em> We model the day-to-day and seasonal/bi-decadal changes in the area-integrals of ionospheric potential (<em>V</em>_<em>i</em>) near the magnetic poles due to solar wind electric field inputs. The overhead value of <em>V</em>_<em>i</em>, divided by the local column resistance (<em>R</em>) determines <em>J</em>_<em>Z</em>, where the conductivity of the column is the result of ionization by galactic cosmic rays (GCRs) and solar and magnetospheric energetic particle precipitation. These vary with time, due to varying solar wind magnetic field inputs, not only on the day-to-day timescale (e.g., Forbush decreases) but also on the decadal and bi-decadal and century timescales. The GCR and energetic particle inputs vary with latitude, due to filtering of particle energies in the geomagnetic field. We compare area-integrals of the amplitude of the <em>J</em>_<em>Z</em> variations due to <em>V</em>_<em>i</em> changes to those due to the <em>R</em> changes, for evaluating their global effectiveness in affecting cloud microphysics and weather and climate changes. The day-to-day and bi-decadal correlated weather and climate variations indicate <em>J</em>_<em>Z</em> rather than other solar forcings as mainly responsible for the correlations. The decadal and longer climate responses to space weather are not large; however, understanding them could help improve predictions of future climate change due to greenhouse gases.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322749","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":"Analyzing trend and forecasting of temperature and rainfall in Shimla district of Himachal Pradesh, India using non-parametric and bagging REPTree machine learning approaches","authors":"","doi":"10.1016/j.jastp.2024.106352","DOIUrl":"10.1016/j.jastp.2024.106352","url":null,"abstract":"<div><div>The changing pattern of climate variables has caused extreme weather events and severe disasters, especially in mountainous regions. Such events have a detrimental impact on resources, environment and society. Thus, it has become imperative to examine the trends and forecasts of meteorological variables using a scientific modelling approach. This study investigates temperature and rainfall trends using the modified Mann-Kendall test and Sen's slope estimator between 1980 and 2021. A Bagging-REPTree machine learning model was utilized for forecasting temperature and rainfall trends for the next 30 years (2022–2051) to understand the temporal dynamics in Shimla district of the Indian Himalayan state. The mean absolute percentage error, mean absolute error, root mean squared error and correlation coefficient were determined to assess the effectiveness and precision of the model. The findings revealed that the frequency of intense rainfall in the district has increased during the monsoon season (June–September) from 1980 to 2021. Significant trends were found in annual rainfall, maximum, minimum and mean temperatures while rainfall during the winter, summer and post-monsoon seasons has shown a declining trend. The forecast analysis revealed a significant trend for rainfall during the monsoon season and an increasing trend in the maximum temperature has been observed during the winter and summer seasons. The analysis has provided sufficient evidence of variability and uncertainty in the behavior of meteorological variables. The outcome of the study may help in devising suitable adaptation and mitigation strategies to combat climate change in hilly regions. The methodology adopted in the study may help in the future progression of the research in different geographical regions for trend and climate forecasting.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142318997","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":"Main features of the geomagnetic effect of the October 14, 2023 annular solar eclipse in the Americas","authors":"","doi":"10.1016/j.jastp.2024.106354","DOIUrl":"10.1016/j.jastp.2024.106354","url":null,"abstract":"<div><p>The purpose of this paper is to investigate temporal variations in the northward, <em>X</em>, eastward, <em>Y</em>, and downward, Z, components of the geomagnetic field recorded during the October 14, 2023 annular solar eclipse, which main features include its annularity, the eclipse occurrence from local dawn to local dusk, its magnitude variation from 0.30 to 0.86, and the longest ever-observed path across the mainland of the Americas, covering latitudes from ∼65°N to 12°S. The analysis was made possible due to the data on temporal variations in the northward, <em>X</em>, eastward, <em>Y</em>, and downward, Z, components of the geomagnetic field collected at thirteen International Real-time Magnetic Observatory Network magnetometer stations (<span><span>https://imag-data.bgs.ac.uk/GIN_V1/GINForms2</span><svg><path></path></svg></span>). The solar eclipse acted to cause non-sinusoidal and quasi-sinusoidal perturbations having temporal durations of 180–240 min in all geomagnetic field components on a global scale (∼8000 km). The <em>X</em>-component experienced the largest perturbations attaining 10–20 nT, and the <em>Z</em>-component underwent the smallest disturbances. The quasi-sinusoidal perturbation amplitude did not exceed 5–6 nT, and the period most often showed variations within 15–40 min. The magnetic effect exhibited a tendency to increase with solar eclipse magnitude, while the magnitude of the effect has been shown to be significantly dependent on geographic coordinates, local time, ionospheric state, and the patterns of ionospheric currents as well. During the solar eclipse, the electron density depletion was estimated to be ∼0.10 to ∼0.40–0.60 when the eclipse obscuration <em>A</em>_<em>max</em> varied from 19% to 82%. The movement of the lunar shadow was accompanied by the generation of atmospheric gravity waves with period of ∼10–80 min and by electron density perturbations with amplitudes of the order of 0.01–0.03. The estimates made on the assumption that the magnetic effect is due to the ionospheric current disruptions show good agreement with the observations.</p></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273890","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 comprehensive evaluation of lightning location accuracy using a weighted gridding method","authors":"","doi":"10.1016/j.jastp.2024.106342","DOIUrl":"10.1016/j.jastp.2024.106342","url":null,"abstract":"<div><div>For the newly built very low-frequency long-range lightning location network (VLF-LLN) in China based on the equivalent propagation velocity method, we have evaluated the probability of deviation distance between the locations results and the reference points by using a weighted gridding method, and have drawn some conclusions. (1) By analyzing the effects of different numbers and configurations of stations on the location deviations, it is found that when the number of participating stations increase, the location deviation relatively decreases, and the numbers and configurations of participating stations has much more effect on the probability of location deviation of the lightning flashes outside the network than those in the network; (2) We statistically analyzed the location deviation for each grid of the network by using a weighted gridding method. The deviation probability using 11-station synchronization as a reference is similar to that for 13-station synchronization per grid. Assuming that the deviation distance is less than 3–5 km, the average location results are almost unchanged when the station number exceeds 7 or 8; (3) Comparing with the Advanced Direction and Time-of-Arrival Detecting network (ADTD), our VLF-LLN has an average deviation value of 3.47 km and a median value of 1.81 km for 63767 lightning flashes, and 90% samples have the location deviation less than 8 km and 54% have the location deviation less than 2 km.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326365","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 case study on the dust storm that occurred on March 13–18, 2022, over the Algerian Sahara, using satellite remote sensing","authors":"","doi":"10.1016/j.jastp.2024.106345","DOIUrl":"10.1016/j.jastp.2024.106345","url":null,"abstract":"<div><p>This study investigates the dynamics of a significant dust storm that occurred in Algeria in March 2022, employing data derived from the Sentinel-5P and CALIPSO satellite instruments. We examine the Aerosol Absorbing Index (AAI) to detect n absorbing aerosols, with a focus on desert dust, and analyze the attenuation coefficient. Additionally, we employ the HYSPLIT trajectory analyze to study dust transport and MERRA-2 to examine wind patterns wind. The key findings unveil a detailed trajectory of a prominent dust storm in Algeria in March 2022. The Aerosol Absorbing Index (AAI) effectively identifies absorbing aerosols, particularly desert dust, through thorough analyses of dust trajectory and wind patterns; augmenting these findings, CALIPSO satellite data has provided a detailed vertical profile of aerosols within the dust plume, emphasizing spatial and altitudinal extents. This research significantly contributes to advancing scientific discussions on atmospheric dynamics in arid regions and enhances our understanding and forecasting capabilities related to Saharan dust storm initiation and trajectory.</p></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242335","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":"Consistency of climatic changes at different time scales in Central England and Greenland","authors":"","doi":"10.1016/j.jastp.2024.106343","DOIUrl":"10.1016/j.jastp.2024.106343","url":null,"abstract":"<div><p>Characteristic variations in the Greenland isotope temperature data over the last 1000 years and in the meteorological temperature measurements collected from Central England during the past four centuries have been analyzed. We take advantage of the continuous wavelet transform to analyze the simultaneous occurrence of temperature variations of different time scales. We assess the extent to which these phenomena can be compared when examining two different northern hemisphere locations at different time scales. Among the long-term variations, we focus on the cooling at the turn of the 18th century, which occurred slightly later in Greenland than in central England, and the warming observed at present. On the short time scale, the range under study is limited to times of the order of 5-10 years. It has been found that it is on these scales that temperature variations in the two locations are relatively consistent, with a cross-correlation coefficient as high as 0.6 for timescales of the order of 9 years. The main solar activity cycle also falls within the interval of significant correlations. It is shown that despite the absence of direct correlation between temperature and solar activity, the time dependence of the wavelet cross-correlation coefficient of the two temperature series on the scale of 11 years reproduces the long-term variations of solar activity.</p></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242336","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":"Investigation of anomalous lightning activity during the January 15, 2022 Tonga volcano eruption based on measurements of the VLF and ELF electromagnetic fields","authors":"","doi":"10.1016/j.jastp.2024.106344","DOIUrl":"10.1016/j.jastp.2024.106344","url":null,"abstract":"<div><p>An anomalous increase in the level of Very Low Frequency (VLF, 3–30 kHz) and Extremely Low Frequency (ELF, 3–3000 Hz) radio noise and the rate of VLF atmospherics was registered during the explosive eruption of the Tonga volcano on January 15, 2022 at the Akademik Vernadsky station (65.246°S; 64.257°W) about 8870 km from the volcano. At the peak activity around 5 UT, the number of atmospherics in 2-min intervals increased by almost 15 times compared to the period preceding the eruption. At this point, the estimated rate reached 360 VLF atmospherics per second. At the same time, an increase in the power spectral density of the magnetic field by 5–9 times was observed in both the ELF and VLF ranges. After 40 min, only on ELF an increased peak lasting ∼10 min was observed, comparable in magnitude to the main peak. According to the Worldwide Lightning Location Network (WWLLN), increased thunderstorm activity was concentrated very close to the volcano during this period. This discrepancy between the intensities of ELF and VLF radiation suggests a significant difference in the parameters of currents in lightning discharges occurring in the area of the volcano vent and in the area of the volcanic ash plume.</p></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232422","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":"Interannual variation of summer southwest monsoon rainfall over the monsoon core regions of the eastern Bay of Bengal and its relationship with oceans","authors":"","doi":"10.1016/j.jastp.2024.106341","DOIUrl":"10.1016/j.jastp.2024.106341","url":null,"abstract":"<div><div>The study looked at how summer monsoon rainfall in the eastern Bay of Bengal area changes from year to year due to Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO). Study used rainfall data and sea surface temperature data to see these variations. It's found that during ENSO positive phase, rainfall decreased in the eastern coastal region of the Bay of Bengal but increased in the northern Indo-Myanmar region. The opposite happened during ENSO negative phase. The study used a special analysis method called EOF and Morlet wavelet power-spectrum analysis to look for important patterns in the rainfall data and did correlation analysis to understand what causes abnormal rainfall in these regions. The study also found that the local convection and water vapor flux during ENSO positive phase are related to the anomalous rainfall in the Monsoon Core region. Rainfall is made stronger by the unusual anticyclone circulation in the upper troposphere. A strong/weak Mainland Indochina southwest monsoon (MSwM) in the positive or negative phase of ENSO can bring excess/less moisture to wet/dry the local southwest summer rainfall. In northern Indo-Myanmar, the anomalous rainfall is not only relied on the intensity of the MSwM but also the frequency of western disturbances also influences the regional rainfall, and further study need to develop.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311564","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}