Eyes in the Sky: NISAR to decode Earth's silent warnings

New Indian Express

3 days ago

On July 8, a local in Upper Mustang, Nepal, noticed an ominous flood wave rushing down the Chhuhama stream above Chumjung and Lo Manthang, close to the iconic Muktinath temple. The source was a rapidly drained glacial lake high on the Kali Gandaki glacier, located above 5,900 meters altitude.
Over preceding weeks, the lake had steadily grown before emptying itself subglacially over 500 meters. Within hours, the floodwaters had ripped apart four downstream bridges, deposited debris across 35 kilometers, and caused substantial damage.
This was the third highest Glacial Lake Outburst Flood (GLOF) ever recorded in High Mountain Asia, and a harsh reminder of how rapidly the cryosphere is changing under pressure from rising temperatures. At some places this year, temperatures soared 5°C above long-term seasonal averages. Experts say the frequency of GLOFs is increasing — with at least eight reported this year across Nepal, China, Afghanistan, Pakistan, and Kyrgyzstan —triggered by rapid ice melt, permafrost thawing, and newly formed glacial lakes.
Now, all eyes are on NISAR, the joint NASA-ISRO Earth observation satellite launched on July 30, which is being hailed as a game-changer in forecasting such disasters and improving climate resilience.
NISAR mission
The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is the world's first dual-frequency radar imaging satellite. It combines L-band radar from NASA and S-band radar from ISRO to monitor Earth's surface changes with unmatched precision — day and night, in all weather conditions.
The first 90 days post-launch are designated for In-Orbit Checkout (IOC), during which systems will be calibrated and tested before full science operations begin. Once operational, NISAR will image the global land and ice-covered surfaces, including islands, sea-ice and selected oceans every 12 days, which experts say is unprecedented.
'NISAR will allow us to detect subtle movements in Earth's surface — including saturated soils on unstable slopes, deformation from earthquakes, and the slow growth of glacial lakes that might not be visible from above,' said Dr Gerald W Bawden, program manager at NASA's Natural Hazards Research Earth Science Division and a key member of the NISAR launch team, told this newspaper.