In recent years, the melting of polar ice has led to an increase in sea level rise. Only the melting of the ice sheets of Greenland and Antarctica has caused the global sea level to rise at a rate of 1 mm per year and has taken up the observed increase in sea level. One third of it, and the rate of increase is still increasing. This is a potential and slow hazard to human survival and economic development. When this hazard accumulates to a certain extent, it will bring disaster to people in many areas (the coastal areas are predominant and will gradually spread inland).
The monitoring of this phenomenon has never stopped. According to reports, NASA (National Aeronautics and Space Administration) plans to launch a laser pointer laser satellite at Vandenberg Air Force Base in California on September 15 and measure the ice surface height of the Earth's polar surface with unprecedented precision. At the same time, understand the reasons that cause the surface ice cover to melt rapidly. The satellite coded for this launch is "ICESat-2", and its measurement range covers the average annual elevation of land glaciers in Greenland and Antarctica. It can capture 60,000 measurements per second in a distance that is only pencil wide.
Michael Freilich, director of the Earth Science Department at NASA's Scientific Missions Council, said: "The latest observations from ICESat-2 can improve our understanding of ice sheet changes in Greenland and Antarctica and grasp the real causes of sea level rise."
ICESat-2 will improve NASA's record accuracy for polar ice height changes over the last 15 years. The previous generation ICESat completed its first measurement mission in 2003 and continued to participate in NASA's “Ice Bridge Action” in 2009. The latter is a space research activity that records the acceleration of the melting rate of ice. ICESat-2 measures the ice height through a more advanced Terrain Laser Altimeter (ATLAS) and then calculates the time it takes for a single photon to return from the spacecraft to Earth.
"Using ATLAS requires us to develop new laser pointer technology and obtain the measurement data scientists need to advance this research," said Doug McLennan, ICESat-2 project manager. “This means we have to design a new type of satellite instrument that not only collects data that looks incredibly accurate, but also collects height measurements that are 250 times higher than the previous generation of satellites.”
ATLAS can transmit 10,000 data per second and emit trillions of photons to the ground through 6 green lights. Since so many photons are returned from multiple beams, ICESat-2 can obtain more detailed surface ice data than previous generation satellites. As it orbits the Earth from the South Pole to the North Pole, ICESat-2 also measures the height of the ice layer four times a year in the polar regions, providing seasonal and annual periodic monitoring of glacial altitude changes. In addition to the poles, ICESat-2 measures the height of land and sea surfaces, including forests.