Measuring Earthshine: How New Terra Data are Improving Weather and Climate Forecast Models

A sensor aboard NASA's Terra satellite is helping scientists map how much sunlight the Earth's surface reflects back up into the atmosphere, and this new detailed information should help to greatly improve weather and forecast models.

The Moderate Resolution Imaging Spectroradiometer (MODIS) now routinely provides daily global and local measurements of albedo, or the total amount of light reflected from Earth's surface out to space. These precise data may allow scientists to better understand and predict how various surface features absorb and reflect solar radiation, which influence both short-term weather patterns and longer-term climate trends.

In a May 2002 issue of Geophysical Research Letters, a team of scientists at Boston University reported that the new albedo measurements match up well with the wide variance of geological features found across the Earth's barren landscapes.

"Zooming in on Africa's Sahara Desert and the Arabian Peninsula, for instance, MODIS observed considerable variability in reflectance across the region-from the darkest volcanic terrains to the brightest sand sheets," said Elena Tsvetsinskaya, the paper's lead author and a researcher at Boston University. "So we can relate specific soil groups and rock types to MODIS-derived albedo measurements."

For the complete article on MODIS providing the amount of light reflection from Earth to space, go to: http://www.gsfc.nasa.gov/topstory/20020624earthshine.html