Surface observations on trace gases such as ozone (O3), oxides of nitrogen (August 2014–May 2017) and carbon monoxide (January 2016–May 2017) were used to investigate O3 chemistry. Study shows O3 concentration is high during winter with a mean value of 35.54 ± 7.16 ppbv and low concentration in monsoon with a mean value of 12.70 ± 3.55 ppbv. Oxides of nitrogen (NOx = NO + NO2) concentrations are high

The importance of gravity waves (GWs) in the redistribution of energy and momentum in the Earth's atmosphere is well known. It is extremely important to understand the nature of variation in the GW characteristics to address issues of coupling in the Earth's atmosphere. We have used digisonde measurements to investigate the variation in thermospheric wave dynamics in the daytime over low-latitudes

The secular variation spatial pattern of geomagnetic cutoff rigidity, Rc, is analyzed considering analytical expressions. Störmer analytic Rc equation in terms of geomagnetic latitude is used considering a pure dipolar field for the centered and eccentric dipole coordinates, together with a dipole-quadrupole superposition simplified equation. Linear Rc time trend for the period 1900–2020 in a 5 ° × 15 °

A local maximum value of ionospheric total electron content (TEC) in midlatitude regions, named midlatitude ionospheric peak in this study, has been frequently observed during both the daytime and nighttime. We have carried out a modeling study of midlatitude ionospheric peaks in TEC using the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM) to investigate possible mechanisms

In this paper, the wavelet packet transform (WPT) is applied to analyze the time-frequency features of three kinds of lightning events (the cloud pulse, the return stroke and the stepped leader) and a new identification method based on WPT is proposed. The magnetic-field data used in this paper were recorded by Nanjing Lightning Location Network in 2018. Firstly, the wavelet spectra of three typical

Comparison of the numerical simulation results with experimental data obtained aboard the CHAMP spacecraft has shown that in the eastern longitudes during the local winter period the parameters of electron temperature (Te) enhancement zone in the subauroral ionosphere undergo significant changes depending on the universal time (UT control) as a result of the formation of the shadow region, almost devoid

This work studies the temporal variation of rain heights in the Sub-Sahelian and Coastal regions of Nigeria using six (6) years Tropical Rain Measuring Mission Precipitation Radar (TRMM-PR) reprocessed data retrieved from the Global Precipitation Measurement (GPM) constellation Satellites and Era-Interim Field of the European Centre for Medium-Range Weather Forecast (ECMWF). The research reveals seasonal

We have analyzed ULF magnetic field emissions data obtained from identical 3- component search coil magnetometers installed at Indian stations of Agra (Geograph. lat. 27.2°N, long. 78°E), Shillong (25.92oN, 91.88oE), and Kachchh (23.78oN, 71oE) for the months of April 2012 and September 2013 in which three major earthquakes occurred, one of magnitude M = 8.5 in Indonesian region and two of magnitudes

Long-term forecasting of solar activity, over a scale of centuries, is of interest in modeling climate. Reconstructions of solar irradiance based on radionuclides span 9.4 to 11.5 millennia. There is evidence of multiple maxima and minima, as well as changes in trend. Analysis of the data yields ambiguous results. Fourier spectra find long cycles in the data, but these are not confirmed in the time

Information on the state of the ionosphere is of great importance for organizing communications in the short-wave range. One of the main methods for estimating the ionosphere parameters is the use of modeling. Most existing ionosphere models rely on the algorithms presented in the recommendations of the Radiocommunication Sector of the International Telecommunications Union. This work shows one of

Ground-based electric field measurements during fair weather and thunderstorms are key parameters for Global Electric Circuit investigations and climate change assessment. We study the variations of near surface electric field during fair weather and thunderstorms. In this work we present daily, monthly and yearly distribution of thunderstorm activity from 2012 to 2019 at different research stations

This paper deals with the observations of stratospheric ozone intruding into the troposphere over the Bharati (69.41° S, 76.19° E) station in Antarctica, made during 35th Indian Scientific Expeditions to Antarctica (ISEA-35) during jet stream conditions. High-resolution multiplatform measurements from radiosonde coupled with ozonesonde, Very High-Frequency (VHF) radar and Micro-Limb Sounder (MLS) and

This work addresses the vertical atmosphere –ionosphere coupling through two cyclonic events AILA (23–26 May 2009) and ‘WARD’ (10–16 December 2009) observed over the North Indian Ocean. Combined ground Digisonde Tirunelveli (8.7oN, 77.8oE) observation, ECMWF reanalysis, and NOAA Outgoing Longwave Radiation data used to reveal the connection between atmosphere –ionosphere system. At the time of tropical

The results of an investigation into whether or not eclipse shadow bands have an atmospheric origin are presented. Using high altitude balloon and ground-based photodiode arrays during the August 21, 2017 total solar eclipse, data revealing the light patterns before and after totality were collected at 600 Hz. These data were then analyzed using spectrograms, which provide information on intensity

Aerosols and cloud interaction remains highly important in the climatic process and its validation with space-based Ozone Monitoring Instrument (OMI) and ground-based observation of Aeronet Robotic Network (AERONET) is therefore essential. OMI and AERONET AODs was logrithmically subset and variations observed in both instruments show spatio-temporal quality of being more noticeable, which could lead

The Annular Solar Eclipse (ASE) occurred on December 26, 2019, which was visible at most of the South Indian subcontinents with greater than 80% obscurity, particularly during the morning hours, and it played a crucial role in the atmospheric dynamics. For the first time, the ground-based measurements have used to investigate the fluctuations of air temperature, relative humidity, atmospheric pressure

In this study, the solar cycle modulation of the connection between boreal winter El Niño-South Oscillation (ENSO) and following summer South Asia High (SAH) are revealed. For El Niño accompanied by low solar cycle (EL & LS) or La Niña accompanied by low solar cycle (LA & LS), the boreal winter ENSO prominently affects the following summer's SAH variation. The SAH is enhanced (weakened) and expanded

Thermodynamic indices have been used as a tool for nowcasting thunderstorms for decades. The present study deals with understanding the variations in threshold values of various thermodynamic indices during pre-monsoon season at two north-eastern Indian stations: Agartala and Guwahati. The study utilises thirty years (1987–2016) of radiosonde data, surface information about thunderstorms, and TRMM

Although the horizontal density structures of the polar ionosphere have been extensively studied mostly using the F-region peak density or total electron content, there are relatively few studies on the vertical density structures. In this review, we present the climatology of the polar ionospheric density not only in the F-region but also in the E-region and topside ionosphere, in comparison with

This study is concerned with the effects of a decrease in the air pollution concentration on the lightning characteristics of two large Brazilian cities. The decrease in air pollution happened from March 20, till April 02, 2020, and it was caused by the social distancing effort to contain the COVID-19 spread in the cities. In São Paulo, the ratio between cloud-to-ground to intracloud flashes and the

Available manually scaled foF2 observations over 50 years on Juliusruh, 33 years on Slough, and 37 years on Rome stations were used to check the association between quiet-time foF2 disturbances (Q-disturbances) and following on isolated magnetic storms. Of course, such cases exist, however Pearson's contingency coefficient, Chi-square and Odds ratio tests applied to check a measure of association gave

This paper presents the ground truth datasets of negative cloud-to-ground (NCG) flashes with one single stroke in five isolated small thunderstorms. By developing a machine-learning method based on the convolutional neural network, we identify the return strokes during the whole life of thunderstorms with the wideband electric field waveform of lightning discharges detected by Jianghuai Area Sferic

The knowledge of the periodic diurnal anisotropy in the cosmic ray (CR) flux intensity as well as the enhanced anisotropy that might accompany Forbush events is not novel. Theoretical models and several methodological approaches such as Fourier techniques developed to predict the diurnal vectors started appearing in the literature since 1960s’. Consequently, the vectors have been successfully calculated

Apparent ionospheric reflection heights estimated using electric field waveforms of negative and positive cloud-to-ground lightning return strokes (-CGs and +CGs) that occurred during the same thunderstorms have been compared. We analyzed electric field waveforms of 101 -CGs and 74 +CGs that were recorded in August 2016 in Florida. For daytime conditions, the mean ionospheric reflection height for

Ionospheric scintillation is quite a common phenomenon over the low latitude regions and in East Africa it is often monitored using measurements from the SCIntillation Network Decision Aid (SCINDA) receivers. The SCINDA receivers over East Africa are characterized by long base lines and data paucity thus offering a huge challenge in the long term scintillation characterization over the region. To alleviate

We present a brief review of observational results contributing to modern ideas on the evolution of stellar activity. Basic laws, derived for both rotation–age and activity–rotation relationships, allow us to trace how the activity of low-mass stars changes with age during their stay on the main sequence. We focus on the evaluation of the activity properties of stars that could be analogs of the young

The present study investigates long-term variation in aerosol optical properties (AOP) and their associated climatic implications over selected cities of Chitral, Gwadar, Karachi, Lahore, Peshawar and Quetta in Pakistan for the period 2005–2018. For this purpose, aerosol optical depth (AOD) and aerosol index (AI) are retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring

We perform a superposed epoch analysis on two groups of selected geospace disturbance events, emerging from single and isolated interplanetary drivers, and resulting in either the enhancement or the depletion of the average relativistic electron Phase Space Density (PSD). We investigate the occurrence of behavioural/temporal patterns of solar wind and geomagnetic parameters, chorus and ULF Pc5 wave

An attempt has been made to understand the effect of the cirrus clouds on the tropical tropopause thermal structure over a tropical station Gadanki (13.45oN, 79.2oE) using regular radiosonde observation at 12:00Z and CALIPSO measurements at the closest proximity to Gadanki during 2006–2013. As the CALIPSO and radiosonde observation timings are not simultaneous, we considered only those cases when cirrus

The present study investigates the annual displacement of ITCZ and its role in forming and strengthening the precipitation systems in the southern part of Iran. To this end, the daily precipitation data of 71 meteorological stations were received. Then, the precipitation systems throughout cold seasons (October to May) were extracted. Next, the systems with maximum precipitation average were selected

Time difference of arrival (TDOA) technique is one of many bases to determine lightning strike location employed in a lightning locating system (LLS). In this technique, at least four measurement sensors are required to correctly locate a lightning strike. Usage of fewer number of sensors will result in non-unique solutions to the generated hyperbolas, and hence wrong lightning strike point. This research

Prior to its discovery, O+ from the Earth's high-latitude ionosphere was not expected to be present in any significant amount in the magnetosphere. It is now known that O+ can dominate ionospheric outflow and dominate magnetotail composition during geomagnetically active times. Observations from the Magnetospheric Multiscale (MMS) mission are used here to illustrate properties of O+ in the dayside

A model of electric discharges at mesospheric altitudes has been developed to explain the nature of optical flashes/transient atmospheric events (TAEs) observed aboard the Russian microsatellites “Universitetsky-Tatyana-1”, “Universitetsky-Tatyana-2” and “Vernov”. The model is based on assumption that large-scale areas with a low space charge density and a low electric breakdown threshold can occur

Contemporaneous multi-instrument ground-based optical and meteor radar observations of OH and O2 airglow, temperature and neutral winds during the winter season of November 2018–February 2019 have been used to investigate the dynamics of the mesosphere/lower thermosphere (MLT) (80–100 km) region in the high Arctic at Svalbard, Norway (78°N, 16°E) and at Eureka, Canada (80°N, 274°E). Temperature observations

The impact of initial conditions in predicting lightning activity using the Weather Research and Forecasting (WRF) with the electrification (ELEC) extra package, known as WRF-ELEC model, has been investigated. The severity, frequency, and some physical and dynamical properties of lightning occurred during 11 years (2004–2014) are considered. Four thundercloud events with distinctive characteristics

An observation of altitude descents in high-frequency enhanced ion line (HFIL) and plasma line (HFPL) are examined, and an alternative explanation are presented. The HFIL and HFPL altitudes should be governed by the dispersion relations of ion acoustic and Langmuir waves respectively, and those altitude descents in HFIL and HFPL may be in consequence of the significantly enhanced electron temperature

The present paper reports the results derived from PM2.5 and PM10 concentrations during October 2016–May 2018 using MICROTOPS-II Sunphotometer and high volume samplers at Varanasi. Observed data were categorized and analyzed in order to understand the nature, source of origin and variability with seasons. Observations showed aerosol mass loading during the post-monsoon 2016 and winter 2017 as compared

Using a numerical model of the ELF radio wave scattering by seismogenic localized non-uniformity, we evaluate the earthquake (EQ) magnitude by using modifications in the power spectra of global electromagnetic (Schumann) resonance. The ionosphere non-uniformity is introduced as a disturbance in the vertical profile of atmosphere conductivity above the earthquake. Three types are considered of disturbance:

The observations of vertical total electron content (VTEC) and L1 and L2 band ionospheric scintillations at an equatorial station, Tarawa (Geomag. Coordinates, 2.68°S, 114.26°W), Kiribati, under a complex severe space weather event of 4–9 September 2017, are presented. The VTEC increased significantly by 1.03 and 1.31 TEC units under M5.5 class flare at 20:28 UT on 04 September and M4.2 flare at 01:03

Trends derived from the Leibniz-Institute Middle Atmosphere Model (LIMA) and the MIMAS ice particle model (Mesospheric Ice Microphysics And tranSport model) are presented for a period of 138 years (1871–2008) and for middle, high and arctic latitudes, namely 58 °N, 69 N∘N, and 78 °N, respectively. We focus on the analysis of mesospheric ice layers (NLC, noctilucent clouds) in the main summer season

The problem of air quality in Warsaw is related with the emission of pollutants from combustion of coal or natural gas in winter and it is a different situation than in other capitals in EU, where transportation is the main source of pollution to the air. In Warsaw, the impact of traffic emission on air quality is clearly visible in the warm season of the year. Therefore, it is important to analyse

Daily harmonics of the ionosphere’s total electron content (TEC) can be mapped using Global Navigation Satellite Systems (GNSS), as recently accomplished by Lean and colleagues. Here those harmonics are determined (over oceans only) by tidal analysis of ionospheric path delay from dual-frequency radar altimetry. Data from TOPEX, Jason-1, and Jason-2 altimeters are used, with focus on periods of medium

In this paper, a 20-year (1991–2010) simulation of dust aerosol emission is conducted by using the global climate model CAM 5.1 (Community Atmosphere Model, version 5.1). The simulation results revealed that North Africa, the Arabian Peninsula and the Middle East, East Asia, Australia, and the other regions respectively account for 60%, 18%, 12%, 2.5% and 7.5% of the global dust aerosol emission. On

In this paper an attempt has been made to investigate the impact of different microphysical (MP) parameterization schemes in simulation of leading convective line with trailing stratiform (TS) squall lines observed over the Gangetic West Bengal (GWB) region of India during the pre-monsoon season of March–May using Advanced Research Weather Research and Forecasting (WRF-ARW). The model is employed to

This paper examines some data mining techniques for lightning prediction. If we indicate by one the lightning event occurrence and by zero the non-occurrence of the event, then we will have a binary classification problem. In some cases, the dataset of lightning event is class imbalance. Thus, in the current research, the method of undersampling will be employed to generate several balanced datasets

Gravity waves play an important role in the propagation of energy and momentum from the lower atmospheric regions into the upper atmosphere. Depending on the varying dissipation conditions, these waves generated in the lower atmosphere can propagate higher into the atmosphere. As the neutrals and plasma share the same volume in the upper atmosphere, these waves affect both these densities as they propagate

The possibility of sporadic E (Es) layer formation in the mid-latitude nighttime lower thermosphere by horizontal homogeneous and inhomogeneous (vertically changing) winds is investigated by analytical and numerical solutions of continuity equation for dominant heavy metallic ions Fe+. The study firstly showed that when ions maximal vertical convergence rate exceeds the diffusive displacement of their

Most of the heavy rainfall comes from the severe convective storms. Convective scale numerical weather prediction with grid-lengths of a few km or less, is capable for a more successful representation of convective scale processes and explicitly representing different types of convective storms. However, despite these high-non-hydrostatic models, in some specific atmospheric cases associated with very

Stable auroral red (SAR) arcs are the consequence of interaction of the outer plasmasphere (plasmapause) with energetic ions of the ring current. In this work the event of SAR arc observation using the all-sky imager (ASI) at the Yakutsk meridian (130°E; 200°E, geom.) simultaneously with the registration of plasmapause and energetic ion fluxes aboard the Van Allen Probe B satellite at the beginning

Data of temperature anomalies from different sites worldwide for the last millennium are used to extract long-term components in global, northern and southern hemisphere temperatures for their quantitative contribution to climate change to evaluate and to search for possible causes. The Method of Global Minimum which is capable of making a self-consistent selection of trends from a data set and singling

Ionospheric disturbance (ID) detected using GPS based Total Electron Content (TEC) measurements are widely used to study the morphology and dynamics of the ionosphere, and its impact on radio communication and satellite based navigation. The IDs normally derived as rate of change of TEC (ROT) between consecutive ionospheric pierce points at uniform time interval implicitly results in non-uniform spatial

The refined Cloud Imaging and Particle-Size (CIPS) cloud wind tracking algorithm is elaborated and the wind product is assessed against the Navy Operational Global Atmospheric Prediction System - Advanced Level Physics and High Altitude (NOGAPS-ALPHA) winds and the horizontal wind model (HWM14) climatological winds. Multiple searching frame sizes are adopted to generate the preliminary wind sets which

Solar flares are large explosions in the sun’s atmosphere. They can damage satellites and overload electrical systems. To manage that risk, finding methods of efficiently predicting future events is very important. In this paper we introduce a full-Sun flare prediction method based on the Hidden Markov modelling with two hidden states. We concentrate on the soft X-ray emission data near the minimum

The present work reports atmospheric opacity at 220 GHz over Indian Astronomical Observatory (IAO)-Hanle during 2006 to 2018. The opacity data were derived from the radiometric measurement of sky-brightness temperature as a function of zenith angle for every 10 min during day and night. Since the operating frequency range is not completely opaque during rainfall or cloudy atmosphere, observations are

Solar flare forecasting is limited by the current understanding of mechanisms that govern magnetic reconnection, the main physical phenomenon associated with these events. As a result, forecasting relies mainly on climatological correlations to historical events rather than the underlying physics principles. Solar physics models place the neutral point of the reconnection event in the solar corona

The response of the atmosphere to solar irradiance and geomagnetic activity is analyzed in experiments with the Whole Atmosphere Community Climate Model (WACCM) under idealized forcings. Four experiments are carried out combining high (H) and low (L) solar radiative forcing with high (7) and low (3) geomagnetic activity: H7 (with high radiative forcing and high geomagnetic activity), H3, (high/low)