What will NISAR study?

NASA-ISRO Synthetic Aperture Radar, which was launched successfully on Wednesday, will help scientists better understand processes involved in natural hazards and catastrophic events such as earthquakes, volcanic eruptions, and landslides.

Sriharikota: Among the significant questions that NISAR will attempt to answer is how much carbon does the Amazon and Congo rainforests hold, and how are these important forests changing over time.

Other science questions that the mission will address are how fast are mountain glaciers advancing or retreating, and how melting glaciers affect water supplies and flooding for downstream populations. These are achievable as unlike optical sensors, NISAR will be able to “see” through clouds and light rain, as well as in darkness and light.

The mission will also observe the miniscule changes that can be seen in Earth’s crust before and after an earthquake, volcanic eruption, or other natural disaster, which help in fast response of the communities involved.

NASA-ISRO Synthetic Aperture Radar, which was launched successfully from here on Wednesday, will also help scientists better understand processes involved in natural hazards and catastrophic events such as earthquakes, volcanic eruptions, and landslides, besides providing a trove of scientific information about Earth’s processes.

Scientists from ISRO and NASA, who jointly built the world’s costliest and powerful earth observation satellite, said NISAR will also provide key global Earth observations such as changes in ice sheets, glaciers, and sea ice, as well as improve understanding of how deforestation, permafrost loss, and fires affect the carbon cycle.

NISAR will undergo a series of actions for about three months before it starts observing the Earth. The mission is a collaboration between teams of scientists and engineers separated by more than 9,000 miles and 13 time zones in the US and India.

NISAR’s data will be processed, stored, and distributed via the cloud and will be available for anyone to use, free of charge. All S-band and L-band data will also be available to government users in India through ISRO’s National Remote Sensing Centre.

The mission capitalizes on the capabilities of synthetic aperture radar to study Earth’s land and ice as the system works by transmitting microwave signals to Earth and then receiving the signals reflected from the surface below, in this case via a massive 39-foot (12-meter) radar antenna reflector that resembles a massive snare drum.

“By interpreting the ways in which the surface has altered the return signal compared to what was transmitted, researchers can discern physical characteristics about the surface. Then, by passing over the same locations on the planet twice every 12 days, they can determine how those characteristics have changed over time,” the NASA said.

When the L-band system and S-band system operate together, the radars will collect data synchronized in time and location, extending the sensitivity of the measurements to objects on the surface in a broad range of sizes.

While S-band data will allow more accurate characterization of shorter plants, such as bushes and shrubs, the L-band data will sense taller vegetation, like trees.

“NISAR will operate in a Sun-synchronous orbit, with its radar antennas pointed in a configuration that will also offer unprecedented coverage of Antarctica. This is crucial for studying the motion, deformation, and melting of the Antarctic ice sheet as it breaks up and melts into the ocean,” NASA added.

NISAR joins a great observatory of NASA Earth satellites studying oceans, land, ice, atmosphere, and vegetation to create a dynamic 3D view of the home planet.