Comparison of TRMM Precipitation Retrievals with Rain Gauge Data from Ocean Buoys

• DOI: 10.1175/jcli3259.1
• Publication Date: 2005-02-28T18:21:27Z
• Authors: Kenneth P. Bowman
• Keywords: Buoy; Orography; Tide gauge

Abstract Four years of precipitation retrievals from the Tropical Rainfall Measuring Mission (TRMM) satellite are compared with data 25 surface rain gauges on National Oceanic and Atmospheric Administration/Pacific Marine Environment Laboratory (NOAA/PMEL) Atmosphere–Ocean Array/Triangle Trans-Ocean Buoy Network TAO/TRITON buoy array in tropical Pacific. The have a significant advantage over island-based for this purpose because they represent open-ocean conditions not affected by island orography or heating. Because is correlated itself both space time, comparisons between two sources can be improved properly averaging and/or time. When comparing individual overpasses, optimal time gauge (centered overpass time) depends area which averaged. For 1° × areas there broad maximum correlation gauge-averaging periods ∼2 to 10 h. Maximum correlations r range 0.6 0.7. larger areas, smaller (because single becomes less representative box) optimum longer. overpasses averaged box, relative rms difference respect centered box ∼200% 300%. 32-day means boxes, 40% 70%. bias estimated correlating long-term time-mean estimates across set gauges. TRMM Microwave Imager (TMI) gives an r2 0.97 slope 0.970, indicating very little Precipitation Radar (PR) comparable numbers 0.92 0.699. results study consistent sampling error statistical model Bell Kundu.