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NASA to launch advanced Laser satellite for measuring change in Earth’s ice

advanced Laser satellite
ICESat-2. Image Courtesy: U.S. Air Force/Vanessa Valentine

A lot of breakthrough developments are poised to happen in fields as diverse as weather forecasting, climate change monitoring and land-use prediction due to cutting-edge research in advanced Laser Satellites. Yesterday ESA launched Aeolus laser satellite, which is the world’s first satellite that would map wind and improvise weather forecasting, disaster management and enable a better understanding of climatic patterns. And next month, NASA will launch an advanced Laser satellite that will measure the change in Earth’s polar caps with unprecedented accuracy.

NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will calculate average elevation change in land coverage extending from Antarctica to Greenland, capturing 60,000 measurements every second. ICESat-2 is slated for launch on 15 September 2018 from Vandenberg Air Force Base in California.

A giant stride forward

ICESat-2 is an extension to NASA’s 15-year-old ICESat mission, which lead to the development of NASA’s Operation IceBridge in 2009.

“The new observational technologies of ICESat-2 – a top recommendation of the scientific community in NASA’s first Earth science decadal survey – will advance our knowledge of how the ice sheets of Greenland and Antarctica contribute to sea level rise,” said Michael Freilich, director of the Earth Science Division in NASA’s Science Mission Directorate.

ICESat-2 demonstrates a giant stride in the capability to measure change in ice height. Its Advanced Topographic Laser Altimeter System (ATLAS) measures height by timing how long it takes individual light photons to travel from the spacecraft to Earth and back.

ATLAS will fire 10,000 times each second, sending hundreds of trillions of photons to the ground in six beams of green light. The roundtrip of individual laser photons from ICESat-2 to Earth’s surface and back is timed to the billionth of a second to precisely measure elevation.

advanced Laser satellite
Image Courtesy: NASA/Adriana Manrique Gutierre

Due to so many photons being continuously emitted from multiple beams, ICESat-2 will provide a highly detailed view of the ice surface than any other previous satellite. The difference between ICESat and its successor is quite stark – consider if the two satellites were flown over a football field, ICESat would take only two measurements – one in each end zone – whereas ICESat-2 would collect 130 measurements between each end zone.

ICESat-2 will measure ice heights along the same path in the Polar Regions four times a year, providing seasonal and annual monitoring of ice elevation changes.

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“ATLAS required us to develop new technologies to get the measurements needed by scientists to advance the research,” said Doug McLennan, ICESat-2 project manager at NASA’s Goddard Space Flight Center. “That meant we had to engineer a satellite instrument that not only will collect incredibly precise data, but also will collect more than 250 times as many height measurements as its predecessor.”

Computing ice change

Each year billions of tones of land ice melt and flows in the ocean, leading to the rise in sea levels across the globe. In the last few years, melting of ice sheets in Antarctica and Greenland have resulted in the raising of sea level by more than 1 millimeter per year, and constituting around one-third of the total rise in sea levels. And this is alarmingly increasing.

ICESat-2 will monitor the ongoing change and enable the scientists to understand and analyze the data for better future predictions and extrapolating the results to other climatic factors.

ICESat-2 will also take the most precise measurement of sea ice freeboard, which is the height of sea ice above the adjacent sea surface. This measurement will help in calculating sea ice thickness and volume.

Even though floating sea ice doesn’t alter sea level upon melting, but its loss has other consequences. Arctic ice cap reflects the sun’s heat back to space and when the ice melts, the water underneath absorbs the heat. This not only affects wind and ocean circulation patterns but also the Earth’s weather and climate patterns.

Beyond the poles, ICESat-2 will measure the height of ocean and land surfaces. ATLAS is designed to measure both the tops of trees and the ground below, which will help researchers estimate the amount of carbon stored in the world’s forests. Researchers will also be able to investigate the height data collected on ocean waves, reservoir levels, and urban areas.

The uses of ICESat-2 are multiple and will greatly benefit both the scientific community and cater to societal needs. For instance, ICESat-2 measurements of snow and river heights could help local governments plan for floods and droughts. Forest height maps, showing tree density and structure, could improve computer models that firefighters use to forecast wildfire behavior. Sea ice thickness measurements could be integrated into forecasts the U.S. Navy issues for navigation and sea ice conditions.

“Because ICESat-2 will provide measurements of unprecedented precision with global coverage, it will yield not only new insight into the polar regions but also unanticipated findings across the globe,” said Thorsten Markus, an ICESat-2 project scientist at Goddard. “The capacity and opportunity for true exploration is immense.”