Drought is a natural disaster that has terrible effects on society and the natural environment. However, accurate detection and measurement of incoming drought events help policymakers control their severe impact by strengthening drought mitigation policies. In this research, we have assessed the suitability of various Copula's models for modeling drought events using two drought indices, i.e., Standardized

In situ flight observations and theoretical analysis are used to investigate the dispersion properties of droplet size distribution (DSD) in continental deep cumulus clouds under the influence of lateral entrainment and mixing processes. The study attempts to relate the spectral width (σr) and relative dispersion (ν) of DSD with liquid water content (LWC), droplet number concentration (Nd) and mean

Lightning discharges can be detected by their electromagnetic field radiation, they can be heard for close distances (up to 20 km or so) because of the shockwaves produced by the fast expansion of the air around the plasma channel, and they can be seen by the radiation that they produced in the visible spectrum. In order to have a complete picture of this natural phenomenon, scientists around the world

Moisture is one of the crucial atmospheric parameters in parameterization schemes and hence it is important to study regional moisture variation with altitude at different temporal scales. ERA-Interim and MERRA reanalysis data for 38 years (1980–2017) is analyzed to study the diurnal, seasonal, and annual variation of relative humidity (RH) with altitudes over Indian land (IND), East Equatorial Indian

Krall et al. (2020) simulated metal ion layers in the E region ionosphere observed by the ISR at Arecibo, by considering vertical ion-motion and convergence driven by zonal and meridional winds. They report that the observed altitude structure is produced if only meridional wind forces are included in the model. Also, layer formation below 110 km, where the ions are very weakly magnetized, is supported

The occurrence of severe and inclusive dust storms has caused a lot of damage every year in the Persian Gulf region and it has destructive environmental effects in this area. The aim of this study is to investigate the monthly changes in the frequency of dust storms over Khark, Kish and Qeshm islands located in the Persian Gulf region during the 10-year period (2007–2017) using satellite and model

The Gledzer-Yamada-Ohkitani MHD shell model is used to describe dissipative events that take place in magnetized plasmas. In this review we summarize a series of works aimed to characterize the fractal features of the GOY shell model using various choices of the forcing terms, as an attempt to model the behavior of the Earth's magnetosphere driven by the solar wind. Usually, stochasticity in the shell

In recent years, it has been found that the Precipitable Water Vapor (PWV) time series derived from ground-based GPS measurements can be used in to forecast precipitation in different regions. However, it is inevitable to consider the impact of several meteorological parameters such as temperature, pressure, relative humidity, water vapor pressure, total cloud cover and day of year (doy) besides PWV

For over a century, the electric Potential Gradient (PG) of the atmosphere has been measured and studied. The local vertical electric field (Ez) is strongly influenced by the presence of lightning, electrified clouds, rainfall, aerosols, and many others. The One Year Electric Field Study-North Slope of Alaska (OYES-NSA) field campaign was established in the summer of 2017 to measure the vertical electric

Gas discharge properties have been calculated, considering electrons, negative ions, positive ions and the metastable singlet delta oxygen molecules, to assess the possibility of ball lightning resulting from an electrical discharge. It is found that if the metastable molecules have very large densities of the order of 1017 cm−3, a stable ball-like plasma of electrons, positive ions, negative ions

We investigate the formation of He+ and O+ multiple-nose structures observed by the Helium, Oxygen, Proton, and Electron instrument onboard Van Allen Probes A on December 2, 2012. Previous studies have suggested that multiple-nose structures can be formed by changes in the convection electric field. However, the specifics of how these changes can produce multiple-nose structures have been left unresolved

We apply a numerical differentiation method for gradients of bending angle (BA) vertical profiles to determine the atmospheric boundary layer (ABL) height. The basic idea to obtain profiles of BA vertical gradient is to minimize an objective functional, with the Tikhonov regularization term being the second order derivative of the function to be determined; the regularization parameter is chosen as

The relativistic electron dynamics in the radiation belts falls into two categories: diffusive processes, in which particles are scattered randomly, and advective processes, in which particles are collectively driven in one direction in energy or space. In this work, we focus on advection which can occur on a timescale faster than diffusion for CME shock compressions of the dayside magnetosphere. Test-particle

We investigated the average polar patterns of ionospheric electron density and the corresponding patterns of scaling features as a function of interplanetary magnetic field orientation. The focus is on the Northern Hemisphere using electron density data recorded on-board ESA Swarm A satellite. The first- and second-order scaling exponents have been evaluated by means of the qth-order structure functions

Lightning activities are distributed asymmetrically over the globe. Satellite images show that the Himalayan region is one of the prone zones of lightning activity. We do not understand such an uneven distribution of lightning activities as of today. To elaborate on the present-day understanding of lightning flashes over the Himalayan region, we have analyzed various atmospheric factors in association

This paper exploits capabilities implicit in DMSP plasma and field data through which users may infer local IGRF magnetic fields (B→0), as well as components of magnetic perturbations (δB→⊥) and plasma drift (V→⊥) vectors perpendicular toB→0. We use relations between V→⊥ andδB→⊥, associated with Region 2 (R-2) field-aligned currents (FACs), consistent with Faraday's law, to determine Alfvénic reflection

The travel of a tsunami wave is accompanied by generation of geomagnetic field perturbation and acoustic-gravity wave (AGW) propagating into the ionosphere. We consider a mechanism of electric current generation by the tsunami wave in the ocean and ionosphere. The electric current in the ocean is generated by motion of conducting seawater in geomagnetic field, and in the conducting ionosphere it is

Atmospheric aerosols are minute particles (1 nm–100 μm) suspended in various layers of the Earth's atmosphere. During meteor showers, huge amount of cosmic debris called meteoroids enters into the Earth's atmosphere. These particles contribute to aerosols in the mesosphere and lower thermosphere. The aerosols emerged from meteor dust particles are having different size. The displacement of the particles

Based on common volume rocket-borne measurements of temperature, densities of atomic oxygen and neutral air, we derived O(1D) nighttime concentrations and corresponding Atmospheric band emission (762 nm). This is one of the first retrievals of the nighttime O(1D) concentration. Recently, Kalogerakis, Sharma and co-workers have suggested a new production path of O(1D) based on the reaction of vibrationally

We present new observations of polar mesospheric clouds (PMCs) from the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) instrument. The OMPS LP limb scattering measurements provide altitude-resolved PMC observations with full global coverage from 2012 to the present. Relative PMC brightness observed by OMPS LP varies between hemispheres due to changes in viewing geometry, consistent with

When conducting experiments on the electric explosion of titanium foil in water, a “strange” radiation was detected, leaving dotted traces on the film. The velocity of the carriers of this radiation was estimated as 20–40 m/s, and their energy, estimated by the Coulomb drag mechanism, turned out to be equal to 700 MeV. Subsequently, it was found that similar traces are formed at various types of high-current

The detailed evolution of different tropical tropopause layer (TTL) parameters, such as tropopause height (cold point (CPH)/lapse rate (LRH)/convective (COH)), its corresponding temperature (CPT/LRT/COT) and TTL thickness in response to recent 2015–16 El Niño event are delineated using high-resolution Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Radio Occultation

Atmospheric tides play a critical role in the dynamics and coupling of mesosphere and lower-thermosphere (MLT). Global Circulation Models (GCMs) that aim to span the lower, middle and upper atmosphere must therefore be capable of reproducing the tides and observations of tides are thus crucial to constrain the models. Here we present the first climatology of the 12- and 24-h tides measured at heights

The World Health Organization (WHO) declared the coronavirus disease of 2019 (COVID-19) as a pandemic due to its widespread global infection. This has resulted in lockdown under different phases in many nations, including India, around the globe. In the present study, we report the impact of aerosols on surface ozone in the context of pre-lockdown (01st - 24th March 2020 (PLD)), lockdown phase1 (25th

The rapid changes of magnetic fields dB/dt that excite large geomagnetically induced currents (GICs) may be associated with quasi-periodic impulsive disturbances of the geomagnetic field with ~10–15 min duration (Ps6 pulsations). The paper proposes a data processing technique for a 2D array of magnetic stations that automatically recognizes eddy current structures in the polar ionosphere and evaluates

Sporadic sodium layers (SSLs) have been observed all over the globe and always has been of great concern. However, most researches on SSLs are based on only nocturnal observations due to strong daytime solar background noise, thus there is still insufficient understanding of the diurnal variation of SSLs. In this paper, a statistical analysis of SSLs observed by a diurnal sodium (Na) lidar at Beijing

The paper presents climatology of the poorly known, particularly at high latitudes, short-period (8- and 6-h) tides observed by meteor radars at high latitudinal stations Tromsø (70°N, 19°E) and Svalbard (78°N, 16°E) based on 16 years (2003–2018) and 18 years (2001–2018) of measurements, respectively. The main focus of this study is to clarify the seasonal variability and vertical structure of the

A new method to remove the dayglow components for auroral observations from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) aboard the Defense Meteorological Satellite Program (DMSP) F16 in Lyman-Birge-Hopfield (LBH) ranges based on the improved Atmospheric Ultraviolet Radiance Integrated Code (AURIC) algorithm is proposed in this study. This method is developed by determining the coefficients

Hydroxyl vibrational excited states OH∗ in the Earth’s ionosphere are investigated numerically in the presence of suprathermal electrons. The latter are included by using a Boltzmann equation numerical solver and a numerical cross-section for electron impact with OH. We have found that important changes in the peak altitude of OH∗ occur when geomagnetic activities vary. In addition, nighttime changes

The middle atmosphere temperature trend and solar cycle have been studied with long-term ground-based and satellite datasets and/or model simulations. Single satellite observations for middle atmosphere temperature are not long enough (less than 2 solar cycles) to derive long-term trend and solar cycle effects with great confidence. Using a nearly 30-year dataset merged from the Halogen Occultation

We report a detailed study of the relationship between solar filament eruption, flare productivity and CME kinematics relevant to Solar Energetic Particle (SEP) events. We analyze kinematics and morphological behaviors of 32 filament eruptions appearing during the Solar Cycle 24, between Aug 14, 2010 and April 18, 2016. For our analysis a high resolution data in different Extreme Ultraviolet (EUV)

An uninterrupted multi-day (6–8 May 2013) ionospheric F-region event with features indicative of medium-scale traveling ionospheric disturbances (MSTIDs) was detected with the Millstone Hill (MH) incoherent scatter radar (ISR). It was later identified, with the addition of Global Positioning System total electron content (GPS-TEC) imaging, as a novel ionospheric phenomenon. This phenomenon is herein

Commercial lightning detection networks offer detailed lightning stroke data upon subscription. Alternatively, the lightning monitoring system can be deployed at lower cost using Very Low Frequency (VLF) signal reception. With that, a dual-class high-intensity lightning recognition algorithm was developed using VLF signal features to identify the severity of lightning occurrence in the vicinity of

The adiabatic and non-adiabatic behavior of relativistic electrons in the outer radiation belt during the 1 June 2013 geomagnetic storm is studied using data from the Van Allen Probes and THEMIS missions. Analysis of the evolution of the plasma pressure shows that the pressure increased by one order of magnitude during the storm reaching a maximum value towards the end or slightly after the main phase

An analysis on the longitudinal structures in the martian upper atmospheric CO2 densities during the 33rd Martian year (earth year: 2015–2017) is reported herein. The CO2 densities in the altitude region of 165–220 km corresponding to the in-bound periapsis orbits of MAVEN NGIMS during different martian seasons have been considered for this study. The data used spans over a longitude region of −180°

The paper implemented a “standard” coupling system in the South China Sea without any further development avoiding to add a new parameterization on ocean-atmosphere-wave interaction. The sea and the waves influenced tropical cyclone (TC) through the interaction between the air and sea fluxes. The performance of the fully coupled atmosphere-ocean-wave model is overall better that of the uncoupled model

The dissipation of acoustic-gravity waves in the thermosphere due to molecular viscosity and thermal conductivity based on a modified system of hydrodynamic equations is studied. A modification of the system of equations consists in additional taking into account in the linearized Navier–Stokes equations and heat transfer additional terms describing the transfer of momentum and energy due to the background

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

Recent studies have shown that day-to-day variability in thermospheric winds (100–300 km altitude) driven by meteorological variability from below affects ionospheric E and lower F regions, highlighting the need for accurate, continuous specification of day-to-day variability throughout the entire atmosphere for geospace weather prediction systems. To better understand the nature of forcing from below

In this paper, we described the basic features and observations bases of the scenario for the substorm expansion phase that we have developed from our research over the past ~10 years. Onset occurs along magnetic field lines of the inner proton plasma sheet, and is first seen in the aurora as beading along the onset aurora arc, which lies near the equatorward boundary of the auroral oval. Growth of

ENSO has significant impact on the precipitation pattern in summer over China. To differentiate the different impacts from El Niño and La Nina, two groups of experiments were conducted using WRF-Chem CO tracer model, with one group for summer 2015 and the other group for summer 2010. The study explained the difference between 2015 and 2010 as strong El Niño and La Nina, respectively, with a perspective

The effect of precipitating high-energy particles on atmospheric physics and chemistry is extensively studied over the last decade. In majority of the existing models, the precipitating particles induced ionization plays an essential role. For such effects, it is necessary to possess enhanced increase in ion production, specifically during the winter period. In this study, we focus on highly penetrating

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

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

Preliminary results from the measurement of potential gradient (PG) for the period of March 2018–February 2019 at the University of Kashmir, Srinagar, (34° 03′ N, 74° 51’ E, 1585 m amsl) India is reported. The annual mean diurnal variation of PG represents typical double-maxima pattern with the primary maximum at 0900–1000 LT and the secondary maximum at 1900–2000 LT which is in accordance with the

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

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

Ionospheric irregularities are small-scale disturbances in the ionosphere which disrupt radio waves by causing amplitude and phase scintillations. Global Navigation Satellite System (GNSS) network can work as two-dimensional array to provide the spatial structure of the irregularities. With derived vertical total electron content (VTEC), we propose a spatial fluctuation of TEC (SFT) parameter to identify

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

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 °

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

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

We study the dynamics of radiation belt electrons during a 10-day quiet period perturbed by substorm activity and preceding a high-speed stream (HSS), aiming at a global description of the radiation belts in L-shell, L in [2, 6], and energy [0.1, 10] MeV. We combine Van Allen Probes observations and Fokker-Planck numerical simulations of pitch-angle diffusion. The Fokker-Planck model uses event-driven

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

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