Assessment of the v2016 NWCSAF CRR and CRR-Ph precipitation estimation performance over the Greek area using rain gauge data as ground truth

The NWCSAF (Support to Nowcasting and Very Short Range Forecasting Satellite Application Facility) software package provides operational products that ensure the optimum use of meteorological satellite data in Nowcasting and Very Short Range Forecasting. The National Observatory of Athens operates NWCSAF since 2016. The rainfall estimates obtained by the Convective Rainfall Rate (CRR) nighttime algorithm and the Convective Rainfall Rate from Cloud Physical Properties (CRR-Ph) algorithm of the 2016 version are verified against rainfall observations provided by the dense network of automated surface weather stations operated by the National Observatory of Athens (NOA) for a full year. For the verification a temporal upscaling to 30 min was applied to all datasets. Overall, CRR overestimates the extent of the precipitation areas while at the same time it underestimates the precipitation totals. CRR-Ph clearly outperforms the CRR nighttime algorithm regarding the accurate delineation of precipitation areas but it overestimates the precipitation totals. Heavier precipitation is consistently detected by both algorithms although the false alarms rate is high. Seasonal variations are found, with the most important the poorer estimation performance during spring.