This successor proposal describes a 3-year plan to build upon work toward the improvement of a very high time and space resolution global precipitation analysis method dubbed �CMORPH�. Because this analysis system ingests precipitation products, rather raw radiance information from which rainfall is estimated, it is extremely flexible and is a viable candidate to be a GPM �Day-1� product that could provide near real time global precipitation analyses at spatial scales of 0.25 x 0.25 degrees of latitude/longitude every half hour as soon as GPM data become available. CMORPH melds together precipitation estimates from four different passive microwave (PMW) instruments from nine different low earth orbiting spacecraft at the present time. The improvements that we propose to make are necessary to further refine the calibration process. Such a process is needed because precipitation products that are generated from instruments with different spectral characteristics will not provide the same value for the same scene. Primarily, we propose to refine and implement procedures to correct for scan angle dependencies and oceanic detection deficiencies that are inherent in the precipitation estimates that are generated from the AMSU-B cross-track sensor. TRMM TCI estimates will then be used as an absolute calibration for all input rainfall estimates before propagation and morphing procedures. This work will be conducted with close interaction with our collaborators at NASA and NESDIS. When the improvements are implemented, we will reprocess the entire CMORPH record and will extend CMORPH analyses back to 1998 which will result in a 10+ year base period by the end of this proposal period.
We also propose the development of a new related product (�RMORPH�) in which rain gauge data are integrated with the satellite estimates. This is an important improvement due to the bias in satellite-derived precipitation estimates over land surfaces. Over areas with dense rain gauge coverage, such as the U.S., we propose the use the CMORPH hourly rainfall estimates to disaggregate the daily rain gauge amounts to hourly amounts. Elsewhere, we propose to use a technique such as �CMAP� to integrate the gauge data with the satellite estimates of precipitation. The RMORPH analyses will also be extended back to1998 and provide a 10+ climatology �research version� of CMORPH.
We also propose to expand our validation work to use daily rain gauge that has been disaggregated to hourly totals using radar data over the US to look more in-depth at individual algorithms at near coincident points in time and to provide feedback to algorithm developers so that their methods can be improved.
Collectively, this work is relevant to two of NASA�s Strategic Goals (Strategic Sub-goals 3A.2 and 3.A.4) and to topics 1.2(1), 1.2(2), 1.2(5), and 1..5(1) of the �Precipitation Science Program�.
