Development of Synthetic Aperture Radar (SAR) based satellites provide remedies to major geohazards under critical situations around the world. Sentinel 1A mission with the revisit period of 12 days helps to serve the objective in an effective manner. With the availability of Interferometric Wide Swath (IW) mode, Sentinel 1A mission is capable of monitoring the surface deformation using InSAR techniques. On November 12th, 2017, an earthquake with a magnitude of 7.3 occurred in the Iran/Iraq border lead to the enormous disaster reaching over 500 victims. The study focuses on measuring the deformation caused due to earthquakes by using Differential SAR Interferometry (DInSAR). VV polarization of Sentinel Data and SRTM DEM are used as an input to GMTSAR for the development of interferogram. Based on the results obtained, it is found that a maximum of 85.1 cm deformation occurred and nearly 1500 km2 of the area is severely affected.

Differential SAR interferometry (DInSAR) techniques is extensively utilized over decades to monitor and detect surface distortion. Interferometric SAR results obtained from Sentinel 1 data experiences phase delay due to interference with the atmospheric water vapour and pressure and DEM is considered as one of the important parameter in topographic phase removal. In the present study an attempt was made to eradicate the atmospheric errors and to assess the variation of LOS displacement w.r.t. different DEM. Results concluded GACOS based atmospheric correction eradicates the atmospheric error and helps in improving the quality of LOS displacement. Comparison of InSAR results by utilising SRTM, ALOS and Cartosat DEM and GACOS concluded that LOS displacement varies based on the accuracy of DEM and its resolution with the minimum error identified by utilising CartoDEM over Kodagu region.

Glacier velocity, the glacier's health indicator, is an emerging research interest in global warming among the scientific community over the current decade. As per scientific reports, due to their stable and advanced nature, the glaciers of Karakoram are exclusive. The present study focuses on understanding the temporal velocity variability of the Siachen Glacier, Shyok Basin, Karakoram using SAR datasets, in the perspective of the difficulties in estimating the glacier velocity over the inaccessible Karakoram Mountain. For the hydrological year 2017-18, 30 sentinel-1 derived interferograms using the DInSAR technique were analyzed to obtain Line Of Sight velocity. The transient velocity of the glacier reflects separate patterns within the glacier for different seasons due to the thermodynamic and orographic system over the glacier surface. In azimuth and range direction, the projected annual LOS velocity to a two-dimensional surface velocity is estimated to be around 103.8 ± 3.1 m/year.

COVID-19 pandemic situation has highly restricted the human movements including public transport, commercial and industrial activities in India since the end of March 2020. With the necessity to demonstrate the effectiveness of local emissions, the study aims in analysing the relative variation of ambient air quality before and during COVID-19 with the aid of in situ measurement and Sentinel 5P space technologies. ESA Sentinel 5P Level 2 data \sets including Carbon monoxide (CO), nitrogen dioxide (NO₂), Sulphur dioxide (SO₂), and Ozone (O₃)were pre-processed in SNAP and QGIS platform for the extraction of air quality parameters. Results concluded that the concentration of air quality parameters CO, NO₂, SO₂, and O₃reduced 50.52%, 85.81%, 71.61% and 313.4%, respectively, between March and June 2020. Accuracy of air quality parameters CO, NO₂, SO₂, and O₃obtained from Sentinel 5P datasets are found to be 89.5%, 83.54%, 86% and 94%, respectively, when compared with the in situ measurements. As a favourable outcome of the COVID 19 lockdown, better air quality is recorded over the vulnerable locations due to the absence of significant activities and with the improvement in the air quality the study illustrates the importance of temporary pollution source control measures in a suitable time interval. Integration of in situ measurements and satellite datasets will remove the conventional barriers and provide spatially distributed observations that can assist the decision-makers in formulating the best air pollution control strategy.