Comparison of TRMM Precipitation Retrievals with Rain Gauge Data from Ocean Buoys
- 1 January 2005
- journal article
- Published by American Meteorological Society in Journal of Climate
- Vol. 18 (1), 178-190
- https://doi.org/10.1175/jcli3259.1
Abstract
Four years of precipitation retrievals from the Tropical Rainfall Measuring Mission (TRMM) satellite are compared with data from 25 surface rain gauges on the National Oceanic and Atmospheric Administration/Pacific Marine Environment Laboratory (NOAA/PMEL) Tropical Atmosphere–Ocean Array/Triangle Trans-Ocean Buoy Network TAO/TRITON buoy array in the tropical Pacific. The buoy gauges have a significant advantage over island-based gauges for this purpose because they represent open-ocean conditions and are not affected by island orography or surface heating. Because precipitation is correlated with itself in both space and time, comparisons between the two data sources can be improved by properly averaging in space and/or time. When comparing gauges with individual satellite overpasses, the optimal averaging time for the gauge (centered on the satellite overpass time) depends on the area over which the satellite data are averaged. For 1° × 1° areas there is a broad maximum in the correlation for gauge-averaging periods of ∼2 to 10 h. Maximum correlations r are in the range 0.6 to 0.7. For larger satellite averaging areas, correlations with the gauges are smaller (because a single gauge becomes less representative of the precipitation in the box) and the optimum gauge-averaging time is longer. For individual satellite overpasses averaged over a 1° × 1° box, the relative rms difference with respect to a rain gauge centered in the box is ∼200% to 300%. For 32-day time means over 1° × 1° boxes, the relative rms difference between the satellite data and a gauge is in the range of 40% to 70%. The bias between the gauges and the satellite retrievals is estimated by correlating the long-term time-mean precipitation estimates across the set of gauges. The TRMM Microwave Imager (TMI) gives an r2 of 0.97 and a slope of 0.970, indicating very little bias with respect to the gauges. For the Precipitation Radar (PR) the comparable numbers are 0.92 and 0.699. The results of this study are consistent with the sampling error estimates from the statistical model of Bell and Kundu.Keywords
This publication has 21 references indexed in Scilit:
- Comparison of TRMM rainfall retrievals with rain gauge data from the TAO/TRITON buoy arrayGeophysical Research Letters, 2003
- Comparing satellite rainfall estimates with rain gauge data: Optimal strategies suggested by a spectral modelJournal of Geophysical Research: Solid Earth, 2003
- Status of TRMM Monthly Estimates of Tropical PrecipitationPublished by Springer Science and Business Media LLC ,2003
- Sampling Errors of SSM/I and TRMM Rainfall Averages: Comparison with Error Estimates from Surface Data and a Simple ModelJournal of Applied Meteorology and Climatology, 2001
- Tropical Rainfall Distributions Determined Using TRMM Combined with Other Satellite and Rain Gauge InformationJournal of Applied Meteorology and Climatology, 2000
- Dependence of Satellite Sampling Error on Monthly Averaged Rain Rates:Comparison of Simple Models and Recent StudiesJournal of Climate, 2000
- A Study of the Sampling Error in Satellite Rainfall Estimates Using Optimal Averaging of Data and a Stochastic ModelJournal of Climate, 1996
- TOGA-TAO: A Moored Array for Real-time Measurements in the Tropical Pacific OceanBulletin of the American Meteorological Society, 1991
- Sampling errors for satellite‐derived tropical rainfall: Monte Carlo study using a space‐time stochastic modelJournal of Geophysical Research: Solid Earth, 1990
- A space‐time stochastic model of rainfall for satellite remote‐sensing studiesJournal of Geophysical Research: Solid Earth, 1987