Dr. Nimalan Swarnalingam, a member of the Ionosphere-Thermosphere-Mesosphere (ITM) Laboratory at NASA Goddard Space Flight Center, has been using satellite and ground-based remote sensing techniques to study significant and complex phenomena in the atmosphere and ionosphere. Dr. Swarnalingam has extensive experience in employing radar techniques. He obtained his M.Phil at the University of Tromso in Norway and his Ph.D at the University of Western Ontario in Canada. In Canada, he focused on the complex phenomenon of polar mesosphere summer echoes (PMSEs). He successfully introduced smaller and less powerful but cost-effective all-sky meteor radar systems into PMSE observations. He conducted coordinated simultaneous radar observations using different systems with primary emphases on investigating the geographical and geomagnetic dependence of PMSEs in terms of calibrated backscattered signals, identifying terrestrial and extraterrestrial factors influencing PMSEs, and developing an aspect sensitivity model to study the radar scattering mechanism of PMSEs. When he joined NASA GSFC, he employed his modeling and experimental expertise to quantify and constrain the radar-observed influx of interplanetary dust particles into the Earth's atmosphere. He developed a radar sensitivity model and applied it to multiple high-sensitivity radar systems to analyze their capabilities and limitations in detecting small and micrometeors, entering with a range of physical and dynamic properties. He also developed a radar response function and determined the altitude distributions for the different radar systems in detecting small and micrometeors originating from different meteor populations.
Dr. Swarnalingam further focuses on the application of satellite-based remote sensing techniques; GNSS radio occultation (RO) and precise orbit determination (POD) limb sounding, to explore the state of global ionosphere under different conditions with primary emphasis on electron density, conductivity, and other key parameters in the F, E, and D regions of the ionosphere. He incorporates ground-based measurements from worldwide ionosondes and radars, as well as GNSS receivers to evaluate and validate new space-borne measurement techniques and mitigating uncertainty. Dr. Swarnalingam utilizes space-borne high-resolution spatial and temporal measurements of electron density to explore the fundamental phenomena and search for critical linkages between drivers and responses of the ionosphere for varying solar and geomagnetic conditions including geomagnetic storms. He uses large datasets from new measurements and associates them with widely utilized ionosphere and space weather operational models to assess and improve their nowcasting and forecasting capabilities.