The second context refers to a precipitation transfer standard. Specifically, this concerns the measurement synergy created by the GMI and the Dual-frequency Precipitation Radars aboard the Core observatory. The mutual overlap of actively sensed, vertically profiled, radar data at two frequencies in combination with the multi-channel passive data is a unique capability of the Core observatory. The GPM radars will be used to accurately measure, via reflectivity and estimates of attenuation, the vertical profiles of the clouds and precipitation, including the drop size distribution. This radar profiled data will be compared to the GMI radiometric retrieval and its derived profile, which are presumed less accurate than that from the radars. As part of the precipitation transfer standard, the radar-measured profiles, and associated radiometer brightness temperatures, are included in an improved database available to the GMI as well as other GPM radiometers.

GPM will transfer Core observatory GMI data to the user community at very short latency. In particular, data from GMI will be continuously transferred via a Tracking and Data Relay Satellite System (TDRSS) Multiple Access (MA) link through White Sands, NM, and into the availability of the user community, typically 15 minutes or less from the time of measurement.

This article was written by S.W. Bidwell, G.M. Flaming, J.F. Durning, and E.A. Smith of NASA’s Goddard Space Flight Center in Greenbelt, MD. For more information, click here.