Washington: Researchers have found a new way to use satellite instruments to get reliable surface temperatures over most of the world`s land area using satellite microwave sensors.
The new technique developed by Dr Roy Spencer and Dr Danny Braswell, both research scientists in the Earth System Science Center at The University of Alabama in Huntsville, uses microwave sensors on NOAA and NASA satellites to collect surface temperature data over virtually all of Earth`s land area.
Although always in use, satellite sensors posed problems.
"The problem has always been that land background is quite variable, which makes it very difficult to model," explained Spencer.
Which means, that due to differences in their microwave emissions, a forest at 70 degrees F and a sandy desert at 70 degrees F look different to the satellite instruments.
Spencer and Braswell, to solve this problem, divided Earth`s land surface into ten basic microwave surface types, ranging from swampy wetland to arid desert. By knowing the mix of land types in each area scanned by the sensor, they can more accurately estimate temperatures for that area.
Their biggest advantage being coverage - the satellite sensors collect temperature data over more than 95 percent of the Earth¹s land area - including portions of Russia and Siberia, Australia, South America, Northern Canada and most of both Africa and the Antarctic.
However, the disadvantage is brevity - The best satellite microwave sensor data used by Spencer and Braswell goes back only to 2002, although previous sensors might allow temperature data to be collected back to 1987.
The finding was presented during the recent Fourth International Conference on Climate Change in Chicago.