A5062311029- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- GNSS positioning and interference
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Tropical and Extratropical Cyclones Research
University of Alaska Fairbanks
2024
Geological Survey of India
2015-2021
Abstract The equatorial zonal electric field responses to prompt penetration of eastward convection fields (PPEF) were compared at closely spaced longitudinal intervals dusk premidnight sectors during the intense geomagnetic storm 17 March 2015. At sector (Indian longitudes), a rapid uplift F layer >550 km and development plasma bubbles (EPBs) observed. These EPBs found extend up 27.13°N 25.98°S magnetic dip latitudes indicating their altitude ~1670 apex. In contrast, few degrees east in...
Abstract An artificial neural network‐based two‐dimensional ionospheric model (ANNIM) that can predict the F2‐layer peak density (NmF2) and altitude (hmF2) had recently been developed using long‐term data of Formosat‐3/COSMIC GPS radio occultation (RO) observations (Sai Gowtam & Tulasi Ram, 2017a, https://doi.org/10.1002/2017JA024795 ). In this current paper, we present an improved version ANNIM was by assimilating additional from CHAMP, GRACE RO, worldwide ground‐based Digisonde...
Abstract Artificial Neural Networks (ANNs) are known to be capable of solving linear as well highly nonlinear problems. Using the long‐term and high‐quality data set Formosa Satellite‐3/Constellation Observing System for Meteorology, Ionosphere, Climate (FORMOSAT‐3/COSMIC, in short F3/C) from 2006 2015, an ANN‐based two‐dimensional (2‐D) Ionospheric Model (ANNIM) is developed predict ionospheric peak parameters, such N m F 2 h . In this pilot study, ANNIM results compared with original F3/C...
Abstract In this paper, we present the preliminary results of a new global three‐dimensional (3‐D) ionospheric model developed using artificial neural networks (ANNs) by assimilating long‐term observations from nearly two decades ground‐based Digisonde, satellite‐based topside sounders, and positioning system‐radio occultation measurements. The 3‐D is named ANN‐based (ANNIM‐3D), which extension previous work on two‐dimensional Sai Gowtam Tulasi Ram (2017a,...
Abstract Using the fan sector backscatter maps of 47 MHz Equatorial Atmosphere Radar (EAR) at Kototabang (0.2°S geographic latitude, 100.3°E longitude, and 10.4°S geomagnetic latitude), Indonesia, spatial temporal evolution equatorial plasma bubbles (EPBs) were examined to classify evolutionary‐type EPBs from those which formed elsewhere drifted into field view radar. A total 535 observed during low moderate solar activity years 2010–2012, out about 210 (~39%) are evolving type remaining 325...
Abstract The ionospheric annual anomaly or nonseasonal of the ionosphere is characterized by globally increased ionization in December solstice than June solstice. Though this phenomenon was reported several decades ago, causal mechanisms have not been fully understood till today. In paper, F 2 layer peak electron density ( N m ) data from Formosa satellite 3/Constellation Observing System for Meteorology, Ionosphere, and Climate‐radio occultation observations during low solar activity year...
Abstract We introduce a new framework called Machine Learning (ML) based Auroral Ionospheric electrodynamics Model (ML‐AIM). ML‐AIM solves current continuity equation by utilizing the ML model of Field Aligned Currents Kunduri et al. (2020, https://doi.org/10.1029/2020JA027908 ), FAC‐derived auroral conductance Robinson https://doi.org/10.1029/2020JA028008 and solar irradiance Moen Brekke (1993, https://doi.org/10.1029/92gl02109 ). The inputs are 60‐min time histories wind plasma,...
Abstract The ionospheric upper transition height ( H T ) is found to increase dramatically by ~100 km from 2008–2009 2010 only for a marginal in solar activity F 10.7 11.76 flux units. latitudinal variation of surface during period exhibits local minimum at equatorial latitudes and low latitudes. Further, the slower rate than These interesting features are new different those reported literature. A quick loss O + ions observed around ~550 650 indicating that charge exchange reaction...
Abstract A double‐peak structure in the peak height of ionospheric F 2 layer around ±10 o geomagnetic latitudes similar to equatorial ionization anomaly was recently reported. This unique feature referred as (EHA). In present paper, a simulation study is carried out using data‐driven artificial neural network‐based two‐dimensional model (ANNIM‐2D) and physics‐based thermosphere‐ionosphere‐electrodynamics general circulation (TIEGCM) understand local time latitudinal variation EHA during main...