Complementary Uses of GEO and LEO Satellite Data in Alaska
September 23, 2020 @ 11:00 am to 12:00 pm AKDT
Speaker: Carl Dierking
Geographic Information Network of Alaska (GINA)
University of Alaska Fairbanks (UAF)
The National Environmental Satellite Data Information Service (NESDIS) which is part of the National Oceanic and Atmospheric Administration (NOAA) operates a number of satellites for monitoring the earth’s environment. These satellites are divided into two types of orbiting strategies.
Geostationary (GEO) satellites orbit at the same speed and direction as the earth’s rotation. Their fixed position relative to the earth provides continuous monitoring of the development and movement of weather systems, however to synchronize with the earth’s rotation their orbit is quite distant from the surface and centered over the equator. This results in degraded resolution and parallax displacement in the high latitudes like Alaska. The newest generation of GEO satellites can take observations as frequently as every 30 seconds.
Polar-orbiting satellites travel from pole to pole covering a new swath of the earth with each pass. They are positioned much lower than geostationary satellites and are often referred as Low Earth Orbiting or LEO satellites. LEO satellites are usually sun-synchronous, covering the entire globe twice a day (once ascending and once descending) and passing over the same point around the same time each day. They have much higher resolution imagery than GEO and minimal parallax, however even with multiple LEO satellites and orbital trajectories converging over northern latitudes, the coverage for Alaska is less frequent than GEO. LEO satellites are often equipped with additional sensors, such as passive microwave which is able to see through clouds.
For Alaska, LEO and GEO satellites have advantages and disadvantages, however other traditional observation networks are sparse in the state, so it is important to utilize the best qualities of each platform to fully diagnose and monitor hazardous natural events. This presentation will show several examples of how data from each of these satellite platforms can be complementary in this process.