Validating three infrared‐based rainfall retrieval algorithms for intense convective activity over Greece

Three different rainfall estimation techniques based on infrared data from Meteosat, the Arkin technique (ARKT), the Negri‐Adler‐Wetzel technique (NAWT) and the Convective‐Stratiform technique (CST), were applied to four convective systems over Greece to test their performance in case of flood episodes of varying intensities and to examine the possibility of their optimization for this particular geographical region. The comparison between satellite‐derived estimates and the corresponding 12‐hourly accumulated precipitation data from ground stations proved that all three techniques have the common characteristic of overestimating the precipitation in Greece. In general, the CST method was found to best represent the rainfall pattern observed in the rain gauge network, when the comparison is made on a single station basis. On the contrary, the overall performances of ARKT and NAWT methods were not satisfactory. Moreover, a sensitivity analysis of the ARKT and NAWT method to their different parameters indicated that the main parameter for improving their overall performance is the threshold temperature whereas the adjustment of the assigned rain rates has little influence on results. In general, the optimized NAWT technique may provide a very good representation of convective rainfall in the particular geoclimatic conditions of Greece, especially if the estimated values are averaged over suitable space‐time intervals.