Precipitation Products' Inter-Comparison over East and Southern Africa 1983-2017

During recent decades East Africa (EA) and Southern Africa (SA) have experienced anintensification of hydrological hazards, such as floods and droughts, which have dramatically affectedthe population, making these areas two of the regions of the African continent most vulnerable tothese hazards. Thus, precipitation monitoring and the evaluation of its variability have becomefundamentally important actions through the analysis of long-term data records. In particular,satellite-based precipitation products are often used because they counterbalance the sparsity ofthe rain gauge networks which often characterize these areas. The aim of this work is to compareand contrast the capabilities of three daily satellite-based products in EA and SA from 1983 to 2017.The selected products are two daily rainfall datasets based on high-resolution thermal infraredobservations, TAMSAT version 3 and CHIRPS, and a relatively new global product, MSWEP version2.2, which merges satellite-based, rain gauge and re-analysis precipitation data. The datasets havebeen directly intercompared, avoiding the traditional rain gauge validation. This is done by means ofpairwise comparison statistics at 0.25 spatial resolution and daily time scale to assess rain-detectionand quantitative estimate capabilities. Monthly climatology and spatial distribution of seasonalityare analyzed as well. The time evolution of the statistical indexes has been evaluated in order toanalyze the stability of the rain detection and estimation performances. Considerable agreementamong the precipitation products emerged from the analysis, in spite of the differences occurringin specific situations over complex terrain, such as mountainous and coastal regions and deserts.Moreover, the temporal evolution of the statistical indices has demonstrated that the agreementbetween the products improved over time, with more stable capabilities in identifying precipitatingdays and estimating daily precipitation starting in the second half of the 1990s.