Evaluation of GPM IMERG Performance Over the Lake Titicaca Basin at Different Time Scales

[摘要] Accurate precipitation measurements are very important as an input for water resources management and various hydrometeorological applications. The Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (GPM) (IMERG) satellite precipitation product (SPP) has been widely used to complement rain gauge measurements. However, it must be evaluated before use and also its application is still lacking in the lake Titicaca basin (LTB). In this research, the evaluation of the performance of GPM IMERG on the LTB at different time scales (daily, monthly and annual) was carried out. The evaluation was performed using rain gauge observations for the period 2003–2016 and three IMERGs, namely early (IMERG-E), late (IMERG-L), and final (IMERG-F). Accordingly, three performance metrics were used that evaluated the accuracy (correlation coefficient, CC), error (root mean square error, RMSE), and bias (percent bias, PBIAS) of the satellite estimates. In general, the monthly IMERG SPP correlated best with the rain gauge measurements. In all the evaluations performed (daily, monthly, and annual), the IMERG-F was in better agreement with the rain gauge measurements at the LTB, with small differences with IMERG-E and IMERG-L. The IMERG SPPs show potential for use in various hydrometeorological applications in the LTB.

[关键词] South American Altiplano;lake Titicaca basin;GPM IMERG;satellite precipitation products