Climatological validation of TRMM precipitation radar monthly rain products over Cyprus during the first 5 years (December 1997 to November 2002)

Abstract

A climatological network of rain gauges operating since 1917 in the island of Cyprus has been used to validate the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar product over the southeastern Mediterranean Sea. A gridded, monthly TRMM product has been used: the so-called 3A-25hr, version-5. All the rain gauges are covered by eight (3A-25hr) 0.5° × 0.5° pixels: between 32° (33.5°) and 34° (34.5°) East (North). The comparison during the first 5 years of the TRMM mission (December 1997-November 2002) shows that quantitative estimates of TRMM Precipitation Radar are remarkably reliable during three (out of four) wettest months: November, December and January. The gauge and TRMM 5-year average is respectively 284 and 279 mm/(3 months). With respect to the previous 81 years, the rain gauges show an increase of rainfall in the rainiest month, December (+19 mm/month), a decrease in January (−40 mm/month) and February (−24 mm/month) and an overall decrease (from 566 mm/year to 520 mm/year). The TRMM Ku-band radar confirms the paradoxical increase of rain in a single month in spite of decrease in total value per year.