TRMM-derived range-adjustment of ground-based radars in two Mediterranean countries

The TRMM Precipitation Radar (TPR) can he used to adjust Ground-based Radar (GR) data, as a function of the range from the GR site. The analysis is based on the average, linear radar reflectivity in circular rings around the GR site for both GR and TPR images. The GR/TPR ratio varies, for the Cyprus radar, on average from approximately -1 dB, at 20 km, to -10 dB at 105 km. For the Israeli radar, it varies from approximately -4 dB, at 20 km, to -7 dB at 105 km. The average departure at the average range is considered to be mainly caused by the calibration of the GR. The range dependence is interpreted to be caused by the increasing sampling volume of the GR with range (overshooting, vertical profile of reflectivity and non-homogeneous beam Filling).