Satellite Observations

By Rick Thoman
Alaska Climate Specialist
Alaska Center for Climate Assessment and Policy
International Arctic Research Center/University of Alaska
Fairbanks

A “miracle” of modern science is the ability to monitor what’s happening in our environment from earth-orbiting satellites.
The first satellite specifically designed for earth observation purposes was the  TIROS-1 satellite  launched by the U.S. in April 1960 and the sensors consisted essentially of a couple of TV cameras.
In its 75 day lifetime it proved the value of space-based information to weather monitoring and forecasting.
Fast forward 65 years, and the information science is able to derive from satellites is beyond anything anyone could have dreamed of in 1960.
Using different wavelengths of light (most not visible to people) in various combinations, it's possible not only to obtain images during the day, but night time images and even moonlight images are now routinely used in day-to-day operations. This time of year, one of the most useful recent products is the "Snow Cloud Discriminator" product, which allows us to distinguish clouds, snow covered ground, snow-free ground, sea ice and open water. The graphic from Sunday morning May 11 clearly shows areas on  the Seward Peninsula  and Norton Sound coast where the winter snowpack has melted away and where it remains. The change from snow cover to bare ground in the spring is important as it immediately changes how heating from the sun is distributed in the environment. Once snow is gone, more of the energy goes to warming the air, thawing the ground and drying out vegetation, which in turn provides  potential fuels for tundra wildfires, as we saw last year with the 7,700 acre Goldbug fire southwest of Buckland.