The use of attenuation for rainfall estimation at C-Band in Argentina

The potential use of specific attenuation (A) for quantitative precipitation estimation (QPE) with a C-band dual polarimetric radar in central Argentina was examined. Argentina currently has two polarimetric radars and in the near future the number of polarimetric radar will increase. Intense convection frequently occurs during spring and summer that affects human activities in this region in South America. For C-Band radars strong attenuation causes the biases in reflectivity measurements in rain, therefore an appropriate attenuation correction is required. Several correction methods using the total differential phase (Φdp) will be presented. First, phase unfolding is performed on measured Φdp. Secondly, specific differential phase (KDP) is estimated. Then A is calculated by using two methods: ZPHI method and the linear relation between A and KDP. High impact convective events are selected to examine the performance of the rainfall estimators R(KDP), R(Z) and R(A). The radar QPEs using these estimators are evaluated by rain gauge measurements on daily accumulation basis. Possible errors caused by presence of hail are analyzed in this study.