Evaluation of TRMM multi-satellite precipitation analysis (TMPA) in a mountainous region of the central Andes range with a Mediterranean climate

Abstract

Estimating the spatial variability of precipitation for hydrological purposes is a challenge, especially in mountainous regions with sparse rain gauges. This study assessed the use of the satellite product Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA) for the rainfall estimation at the local and regional level, on a daily and monthly basis. The evaluation was carried out in a mountainous region of the central Andes Range with a Mediterranean climate. The performance of the satellite estimation was carried out using categorical metrics, residual methods, and correlation and efficiency measures. The local analysis showed that TMPA product performance was better for rainfall events of medium magnitude. Regional analysis results suggest that TMPA products are able to capture the mean spatial pattern for flat areas on a monthly basis. However, the intercomparison in the mountains is likely not reliable, because there are not enough rain gauges to enable a spatial comparison in this area. The satellite estimates also tend to miss precipitation that is enhanced by flow lifting over the mountains. Moreover, the low performance is because the precipitation in the study site is predominantly produced by frontal mechanisms, where the ice content is also lower than that from convective origin.