Evaluación de imágenes satelitales de precipítaciones GPM (Global Precipitation Measurement) a escala subdiaria para la provincia del Azuay

Abstract

Precipitation is an important meteorological variable in the hydrologic water cycle. Therefore, it becomes essential to measure and analyze precipitation behavior. In order to improve precipitation estimations, it is that satellite products have become a valuable tool. They provide spatially continuous data and at regular time intervals such as monthly, daily and sub-daily. One of the latest released products of remote sensing for precipitation are the GPM mission (Global Precipitation Measurement). The aim of this work is to evaluate precipitation estimates for the 3IMERGHH V03 algorithm at sub-daily scale (30 minutes) using series of continuous data from 7 meteorological stations belonging to the Department of Water Resources and Environmental Sciences at the University of Cuenca (IDRHICA). The study area is the Province of Azuay and the analysis period is from March 12th to December 31st, 2014. Results show that sub-daily satellites images qualitatively represented precipitation compared to rain gauges. However, the results of statistical errors and detection rates were not satisfactory for the sub-daily scale. The difference is attributed to the complex topography and climate and the small number of rain gauges in the study region used by GMP for image correction. In particular, satellite images overestimated precipitation for PiscícolaChirimachay, Virgin Cajas, Toreadora and Susudel rain gauges (Quinuas basins and Jubones micro-basins). While they underestimated for Principal, Base and San Fernando rain gauges located in the micro-basin of Zhurucay. In addition, it was shown that satellite images have better performance as the time scale increased, i.e. they are more reliable at daily than at sub-daily scale. These results allow us to recommend the use of these images for applications requiring temporal scales superior to daily.