A new sensor orbiting the Earth aboard NASA’s Terra satellite is now collecting the most detailed measurements ever made of the sea’s surface temperature every day all over the globe. Like a sophisticated thermometer in space, the Moderate-resolution Imaging Spectroradiometer (MODIS) is helping Earth scientists advance studies of how our world's oceans and atmosphere interact in ways that drive weather patterns and, over the long term, define our climate.

Comparing MODIS’ space-based measurements with surface measurements collected from ships and buoys, the MODIS team finds the satellite sensor measures sea surface temperature accurate to within about 0.25°C, which is better than twice the accuracy of previous satellites. Daily global measurements of sea surface temperature (SST) accurate to within half a degree has been a goal of oceanographers for decades. The MODIS team presented their new data product today at the Ocean Sciences 2002 Meeting of the American Society of Limnology and Oceanography and the American Geophysical Union in Honolulu.

"When you look at the signatures of various processes in the climate system you really need to drive the error of SST measurements down to 0.1 or 0.2 of a degree so you can monitor changes on yearly and decadal time scales to understand the mechanisms driving the system," Brown explains. "The mechanisms that cause temperature changes have subtle signatures, over time and space, so you need a high degree of accuracy to determine which mechanisms are causing the change."