Isro helps with timely updates

During the last fortnight's unprecedented floods and landslides in Kerala, there was technologically helpful support for the authorities via updates from the Indian Space Research Organisation (Isro) and its various satellites.

A set of remote sensing and radar satellites has been taking pictures of various aspects, 400-800 km away from the earth. And, sending it back with supportive data. Once processed, these helped experts to predict the level of rain till then, what to expect in the next few hours and even the situation in forests and reservoirs.

For instance, Resources at-2, launched in April 2011, is helpful in taking pictures of forests and other terrain, including water bodies. Scat Sat-1 tracks the wind, how it flows over the sea and over land, helping to forecast the weather. Insat-3DR, with other satellites, can communicate how clouds are positioned; with Scat Sat-1, experts can conclude how fast these are moving. Insat satellites would send data every half an hour.

Microwave remote sensing techniques have an advantage in that electromagnetic radiation penetrates clouds and senses all surface hydrological characteristics. The data from Scat sat-1 (launched September 2016) has been used to detect flood situations over India.

Merging of back-scattering and brightness temperature data help to delineate regions which are flooded, partially submerged or in different soil wetness conditions. “When we have a good number of satellites, we know the situation yesterday and today. We will be able to assess the situation and come to an understanding on what to expect next.