Efecto de advección sobre la acumulación de lluvia espacialmente distribuida usando imágenes de un radar meteorológico

Abstract

Weather radar networks are an excellent tool for Quantitative Precipitation Estimation (QPE), due to their high resolution in space and time, particularly in remote mountain areas such as the Tropical Andes. Nevertheless, the reduction of the temporal and spatial resolution might severely reduce the quality of QPE. Thus, the main objective of this study was to analyze the impact of spatial and temporal resolution of radar data on the cumulative QPE. For this, data from the world's highest X-band weather radar (4450 m a.s.l.) located in the Andes of Ecuador (Paute river basin) and from a rain gauge network were used. Different time resolution (1-, 5-, 10-, 15-, 20-, 30- and 60-min) and spatial resolutions (0.5, 0.25 and 0.1 km) were evaluated. An optical flow method was validated for eleven rainfall events (with different features) and applied to enhance the temporal resolution of radar data to 1-min intervals. The results show that 1-min temporal resolution images are able to capture in detail rain event features. The radar-rain gauge correlation decreases considerably when the time resolution increases (r from 0.69 to 0.31 for time resolution from 1-min to 60-min). No significant difference was found in the total water volume (3%) calculated with the three spatial resolutions data. Spatial resolution of 0.5 km on radar imagery is suitable to quantify rainfall in the mountain Andes.