Simultaneous measurements of ambient atmospheric black carbon (BC) mass concentrations and radiative fluxes were carried out over Satopanth glacier in the central Himalayas from September 22 to October 2, 2016, as a part of a glacier campaign experiment. The daily mean atmospheric BC concentrations varied between 165 ± 20–263 ± 32 ng m−3 with a mean of 199 ± 54 ng m−3 during the observational period

There are several reports about thermal anomalies associated with the impending earthquakes (EQs); among which the underlying mechanism is linked with the main shock with long, intermediate and short-term precursors. In this paper, we analyzed thermal anomalies from Moderate Resolution Imaging Spectroradiometer (MODIS) based Land Surface Temperature (LST) of three different magnitudes and shallow depth

Using data from GNSS networks spanning the European-African sector, the occurrence of ionospheric irregularities induced during the geomagnetic storm of 6–8 March 2016 was studied. During the main phase of the event, strong and unusual mid latitude irregularities were detected at 50º-60ºN on the night of March 6, 2016 before midnight and in the early hours of March 7, 2016. At the low latitudes, intense

Since 1999 radar continuous observations of polar mesospheric echoes have been conducted on the Norwegian island of Andøya (69.30°N, 16.04°E), with the ALWIN radar (1999–2008) and MAARSY (since 2011). Traditionally these observations have been named after their seasonal occurrence, i.e., Polar Mesosphere Summer Echoes (PMSE) and Polar Mesosphere Winter Echoes (PMWE). PMSE are much stronger than PMWE

We report a unique simultaneous occurrence of two plasma structures using a 630.0 nm all-sky airglow imager in Hanle, India. The characteristics indicate that the observed structures are Medium Scale Travelling Ionospheric Disturbances (MSTIDs) of different types, namely periodic and single dark band. Based on previous understandings of Perkins instability, we explore the role of polarization electric

A long-term statistical analysis of thermospheric tides in an altitude range from 150 to 400 km is presented. The analysis is based on a dataset with 31 multi-day experiments conducted from an incoherent scatter radar at Arecibo Observatory between 1984 and 2015. This is the first time that the climatological mean and seasonal variations of the thermospheric tides and their response to solar activities

Ground-based microwave radiometer (MWR) is with ability to measure liquid water path (LWP) and cloud base height (CBH) with the aid of infrared thermometer (IRT) under all skies. Using the 6-year MWR observations at Wuhan (WH), Xianning (XN) and Jingzhou (JZ) in central China, variations of cloud occurrence frequency (COF) and LWP as well as vertical structure of COF for non-precipitating clouds are

The atmospheric surface layer turbulence statistics and surface fluxes during the winter season over Anantapur, a semi-arid region, are investigated using sonic anemometers mounted 10 m and 18 m above ground level on a 32-m meteorological tower. This paper aims to investigate the applicability of Monin–Obukhov similarity theory and to understand the influence of wind speed on the turbulence intensities

The understanding of the excitation mechanism of the sodium D-line nightglow emission is important for many investigations of atomic sodium in the upper mesosphere region. In 1939, Sidney Chapman proposed a first scheme of the chemical reactions involving sodium and ozone to explain the yellow sodium line doublet in the terrestrial nightglow. Later, it became clear that this mechanism could not explain

An attempt is made to connect the moisture present above the boundary layer and its association with the cloud development and boundary layer turbulence using Large Eddy Simulation (LES) and aircraft observations. The dry boundary layer (BL) with shallow clouds observed during Cloud-Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) over the arid Indian peninsula is investigated

Hybrid simulations, where ions are treated kinetically and electrons as a fluid, seek to describe ion microphysics with maximum physical fidelity. The hybrid approach addresses the fundamental need for space plasma models to incorporate physics beyond magnetohydrodynamics. Global hybrid simulations must account for a wide range of both kinetic ion and whistler/Alfvén wave spatio-temporal scales in

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

Seasonal variability in the vertical distribution of ozone over a tropical station, Thumba (8.5°N, 76.9°E) is investigated using nine-years (2011–2019) of ECC ozonesonde data obtained as part of Tropical Tropopause Dynamics (TTD) campaigns. Ozone exhibits a clear annual variation in the lower troposphere (0–2 km) with winter maximum (49.2 ± 3.6 ppbv) and summer monsoon minimum (21.9 ± 0.7 ppbv). In

Trends in meteorological variables have become clear. However, temporal variations and climate oscillations are less clear, especially for extreme events. This study investigates temporal variations in extreme daily precipitation, extreme daily maximum and minimum temperature (Tmax and Tmin) during the last decades in Shaanxi Province, China, by a quantile perturbation method with a nonparametric bootstrap

Solar UV-A radiation causes photocarcinogenesis and skin photoageing, but it could also benefit cardiovascular health and protection from autoimmunity. In this study, a method for the near real-time monitoring of UV-A solar radiation dose based on Earth Observation satellites imagery is proposed. The calculated satellite-derived radiant dose has been compared to ground measurements provided by Public

The scale height in the plasmasphere (HP) is an important factor to present the dynamic nature and variations of the plasmasphere. It is challenging to build reliable plasmaspheric scale height model because of poor coverage and limited continuity of plasmaspheric sounder data. In this paper, an empirical orthogonal function (EOF) analysis method is applied to organize the HP obtained from total electron

The scalar forward propagation equation, most often with the parabolic approximation, has been used extensively for simulating ionospheric radio propagation. More recently, the formalism has been applied at HF frequencies where external magnetic field effects must be accommodated. This paper presents a generalization of the forward propagation equation to accommodate vector fields with forward-marching

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

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

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

This study extends the investigation of quasi-periodic ripples in the F-region electron content reported by Birch and Hargreaves (2020a) to determine their flow velocity and wavelength, using data from the EISCAT Svalbard radars (the 42m antenna being field-aligned and the 32m scanning in a circular pattern at a fixed angle from the field). The ripples were extracted from the 42m electron content between

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

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

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

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

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

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

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

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

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 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