Differences of Rainfall Estimates over Land by Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and TRMM Microwave Imager (TMI)—Dependence on Storm Height
- 1 March 2005
- journal article
- Published by American Meteorological Society in Journal of Applied Meteorology and Climatology
- Vol. 44 (3), 367-383
- https://doi.org/10.1175/jam-2200.1
Abstract
It is well known that precipitation rate estimation is poor over land. Using the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and TRMM Microwave Imager (TMI), the performance of the TMI rain estimation was investigated. Their differences over land were checked by using the orbit-by-orbit data for June 1998, December 1998, January 1999, and February 1999, and the following results were obtained: 1) Rain rate (RR) near the surface for the TMI (TMI-RR) is smaller than that for the PR (PR-RR) in winter; it is also smaller from 0900 to 1800 LT. These dependencies show some variations at various latitudes or local times. 2) When the storm height is low (8 km), the PR-RR is smaller. These dependencies of the RR on the storm height do not depend on local time or latitude. The tendency for a TMI-RR to be smaller when the storm height is low is more noticeable in convective rain than in stratiform rain. 3) Rain with a low storm height predominates in winter or from 0600 to 1500 LT, and convective rain occurs frequently from 1200 to 2100 LT. Result 1 can be explained by results 2 and 3. It can be concluded that the TMI underestimates rain with low storm height over land because of the weakness of the TMI algorithm, especially for convective rain. On the other hand, it is speculated that TMI overestimates rain with high storm height because of the effect of anvil rain with low brightness temperatures at high frequencies without rain near the surface, and because of the effect of evaporation or tilting, which is indicated by a PR profile and does not appear in the TMI profile. Moreover, it was found that the PR rain for the cases with no TMI rain amounted to about 10%–30% of the total but that the TMI rain for the cases with no PR rain accounted for only a few percent of the TMI rain. This result can be explained by the difficulty of detecting shallow rain with the TMI.Keywords
This publication has 23 references indexed in Scilit:
- The Diurnal Cycle of Rainfall and Convective Intensity according to Three Years of TRMM MeasurementsJournal of Climate, 2003
- Next generation of NOAA/NESDIS TMI, SSM/I, and AMSR‐E microwave land rainfall algorithmsJournal of Geophysical Research: Solid Earth, 2003
- Spectral representation of rain profiles and diurnal variations observed with TRMM PR over the equatorial areaGeophysical Research Letters, 2002
- Combined Use of the Radar and Radiometer of TRMM to Estimate the Influence of Drop Size Distribution on Rain RetrievalsJournal of Applied Meteorology and Climatology, 2000
- TRMM Radar Observations of Shallow Precipitation over the Tropical OceansJournal of Climate, 2000
- Discrepancy between Gauges and Satellite Estimates of Rainfall in Equatorial AfricaJournal of Applied Meteorology and Climatology, 2000
- Special sensor microwave imager derived global rainfall estimates for climatological applicationsJournal of Geophysical Research: Solid Earth, 1997
- A Passive Microwave Technique for Estimating Rainfall and Vertical Structure Information from Space. Part I: Algorithm DescriptionJournal of Applied Meteorology and Climatology, 1994
- A Satellite Passive 37-GHz Scattering-based Method for Measuring Oceanic Rain RatesJournal of Climate and Applied Meteorology, 1986
- ERRORS INHERENT IN THE RADAR MEASUREMENT OF RAINFALL AT ATTENUATING WAVELENGTHSJournal of Meteorology, 1954