The TRMM Multisatellite Precipitation Analysis (TMPA): Quasi-Global, Multiyear, Combined-Sensor Precipitation Estimates at Fine Scales

Abstract

The Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) provides a calibration-based sequential scheme for combining precipitation estimates from multiple satellites, as well as gauge analyses where feasible, at fine scales (0.25° × 0.25° and 3 hourly). TMPA is available both after and in real time, based on calibration by the TRMM Combined Instrument and TRMM Microwave Imager precipitation products, respectively. Only the after-real-time product incorporates gauge data at the present. The dataset covers the latitude band 50°N–S for the period from 1998 to the delayed present. Early validation results are as follows: the TMPA provides reasonable performance at monthly scales, although it is shown to have precipitation rate–dependent low bias due to lack of sensitivity to low precipitation rates over ocean in one of the input products [based on Advanced Microwave Sounding Unit-B (AMSU-B)]. At finer scales the TMPA is successful at approximately reproducing the surface observation–based histogram of precipitation, as well as reasonably detecting large daily events. The TMPA, however, has lower skill in correctly specifying moderate and light event amounts on short time intervals, in common with other finescale estimators. Examples are provided of a flood event and diurnal cycle determination.

Evaluation of Drought Indices Based on Thermal Remote Sensing of Evapotranspiration over the Continental United States

“…While real-time precipitation analyses of reasonable quality are available over most of the United States (e.g., McEnery et al 2005), many parts of world lack sufficiently dense radar and rain gauge networks. Satellite-derived global precipitation products provide improved spatial coverage (Huffman et al 2007;Joyce et al 2004), but they are known to exhibit seasonally and spatially dependent biases (Villarini et al 2009;Zeweldi and Gebremichael 2009). Drought classifications from prognostic water balance models (e.g., NLDAS) depend strongly on the assumed model physics, dynamic forcings, and subsurface properties (Mo 2008), requiring information about soil-moisture-holding capacity and retention characteristics that is difficult to obtain with adequate accuracy over large areas.…”

Dynamical Precipitation Downscaling for Hydrologic Applications Using WRF 4D-Var Data Assimilation: Implications for GPM Era

“…Since December 1997, the Tropical Rainfall Measuring Mission (TRMM) has been providing a wealth of spaceborne precipitation data. Among these, the TRMM Multisatellite Precipitation Analysis (TMPA) has provided 3B42 rainfall products at resolutions as fine as 0.258 3 0.258 in space and 3 h in time over the tropics, which covers 508N-508S (Huffman et al 2007). The success of the TRMM has led to the Global Precipitation Measurement (GPM) mission, which consists of a core observatory and a complementary set of existing and new satellites that will be cross calibrated and operated as a constellation.…”

Disagreements in Low-Level Moisture between (Re)Analyses over Summertime West Africa

“…This product uses a combination of spaceborne radar, and microwave and infrared radiance data, to create 3-hourly rainfall estimates at 0.258 3 0.258 resolution (Huffman et al 2007). A limitation of TRMM is that over the period being studied the availability of satellite products has varied (primarily due to the introduction of new satellites), meaning that accuracy varies with time.…”