D3R Set Up to Measure Rain (IMAGE) NASA/Goddard Space Flight Center Caption Set up on a ranch in Rutherford County, N.C., NASA's Dual-frequency, Dual-polarization, Doppler Radar (D3R) is one of several ground radars measuring rain as it falls from clouds. It has the same two frequencies as are on the GPM Core Observatory Satellite. Credit Image Credit: NASA/David Wolff Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.