By Dave Mosher August 31, 2011

NASA has totaled the impressive rainfall from Hurricane Irene using highly precise microwave measurements from a satellite.
The map, created using data recorded by the Tropical Rainfall Measuring Mission (TRMM) satellite from Aug. 20-29, reveals rainfall in some bands of the now-dissipated 10-day-long storm exceeded 2 inches per hour.
“Hurricane Irene was dropping tremendous amounts of rainfall over the eastern United States during a part of this period,” said TRMM team member Hal Pierce of NASA’s Goddard Space Flight Center in a press release.
To gauge rainfall levels, the satellite relies on an instrument that measures microwave radiation. Flat water looks cold because of it doesn’t emit microwave radiation as readily, but round raindrops falling from clouds do and appear warm. By running calculations of the cold/warm contrast over oceans, TRMM can accurately assess rainfall totals.
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