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DAAC-TRMM-3B31
This dataset is created from the TRMM products 2A12 and 2B31 in the GSFC Earth Sciences (GES) Distributed Active Archive Center (DAAC), NASA.
The data of 2B31 is the combination data from the TMI (TRMM Microwave Imager) and PR (TRMM Precipitation Radar). The PR measures the 3-D rainfall distribution over both land and ocean, and defines the layer depth of the precipitation. The TMI is a nine-channel passive microwave radiometer, which builds on the heritage of the Special Sensor Microwave/Imager (SSM/I) instrument flown aboard the Defense Meteorological Satellite Program (DMSP) platforms.
The data of 2A12 is the TMI Level 2 Hydrometeor Profile Product. It includes the vertical profiles of hydrometeors from TMI brightness temperatures by blending the radiometric data with dynamical cloud models. For each pixel, the algorithm assigns a surface type (land/ocean/coast) and a freezing height; and computes surface rain, convective surface rain, and profiles of hydrometeors (cloud liquid, cloud ice, water vapor, etc.) at 14 vertical levels.
Output data of 2A12 and 2B31 are input to the 3B31 and then accumulated for each month at 0.5 grid elements. Monthly surface rainfall totals are derived by multiplying the mean rainfall rate by the total number of hours in each month. Because the rain water content profile of 2A12 and rain rate profile of 2B31 are output at different vertical resolutions, averaging the outputs of 2B31 over several radar range gates to match the 14 layers of 2A12 is necessary. Also, the rain rate (mm/hr) at each radar gate in 2B31 is converted into rain water content (g/m3) to match that in 2A12.
| Variables | Surface rain from 2A12 (mm), convective surface rain from 2A12 (mm), cloud water (mm), rain water (gm^-3) from 2A12, cloud ice from 2A12(gm^-3), mean graupel from 2A12 (gm^-3), latent heating from 2A12 surface rain from 2B31 (mm), rain water from 2B31 (gm^-3), surface rain from 2A12 where 2A12 and 2B31 overlap (mm), convective surface rain from 2A12 where 2A12 and 2B31 overlap (mm),surface rain from 2B31 where 2A12 and 2B31 overlap (mm),ratio of 2B31 to 2A12 surface rainfall from the swath overlap region (%), ratio of 2B31 to 2A12 surface rainfall calculated from the swath overlap region(%) |
| Zonal | Global by 5 deg |
| Meridional | 37.5S to 37.5N by 5 deg |
| Vertical |
14 levels |
| Temporal | Dec 1997 to Jun 2003 by 1 month(s) |
| Static? | no |
| Volume | 28.5MB |
| Server | DODS & LAS; public |
| Source | http://disc.sci.gsfc.nasa.gov/precipitation/TRMM_README/TRMM_3B31_readme.shtml |
| Acquired | Jul 17, 2003 |
| APDRC contact | Yongsheng Zhang |
| Supplements | readme.f |
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