Evaluation of CMORPH V1.0, IMERG V07A and MSWEP V2.8 Satellite Precipitation Products over Peninsular Spain and the Balearic Islands

Abstract

Climate change is altering the global distribution of precipitation, especially in Mediterranean areas with heterogeneous climates. The spatiotemporal variability of precipitation complicates its monitoring. Satellite-derived precipitation products (SPPs) usually offer global continuous coverage at daily scale; however, their coarse spatial resolution and indirect measurement introduce relevant bias. We analysed the suitability of CMORPH V1.0, IMERG V07A and MSWEP V2.8 across Peninsular Spain and Balearic Islands using Agencia Estatal de Meteorología (AEMET) gauge data as reference, and investigated performance dependence on seasonality, precipitation intensity, altitude and orography. CMORPH is not recommended and MSWEP is preferable over IMERG, although MSWEP performs worse for lighter intensities and summer. IMERG and MSWEP show mainly Correlation Coefficient (CC) and Probability of Detection (POD) >67%, and False Alarm Ratio (FAR) >30% (vice versa for CMORPH). All products overestimate with lower frequency but greater magnitude (at least twice the reference value). Monthly performance is better than daily, but with increased underestimation. Performance for spring and autumn is similar to overall performance, while summer presents the most divergent patterns. For heavier intensities, all products improve their correlation with reference data and their detection capabilities, but also increase their underestimation rate and magnitude. Worst performance occurs in those regions with simultaneously higher orographical complexity, annual precipitation and altitude. These SPPs should be used with caution, and we recommend first analysing their performance on the specific application of interest.