Estudio del ciclo diario de precipitación en la cuenca del Paute para validación de modelos regionales de clima

Abstract

Rainfall is one of the most important components of the hydrological cycle. The study ofthe variability of thediurnal cycleof precipitation is animportant input for calibratingglobal circulation modelsthat performclimate change projections. These models must be verified with current data, which so far has not been completed because the space-time variability of rainfall in lower time scales than a month is unknown. There are not studies of diurnal cycle in Ecuador, that why the subject deserves importance. Thus, the purpose of this study is the analysis of the rainfall daily cycle (hourly time scale) for the validation of Regional Climate Models (RCM). The Paute Basin was chosen because of its economic relevance for the country. Analysis of 12 rainfall station with hourly time series of 56 months from January 2009 to August 2013, showed a high variability of the diurnal cycle in monthly and seasonal level. The aggrupation of the data, studied with the cluster k-means analysis, confirmed the heterogenic behavior of rainfall in the basin. Regime, location and altitude of rainfall stations does not influence in the behavior of the daily cycle, and does not allow to find a relation with the patterns of behavior. It was also observed that thediurnal cycleinBM1andBM2regions, has a similar distributionof daily precipitation in seasonalperiods analyzed, mostlyvaryingin magnitude. Hypothesis were raised for the rainfall process observed: (i) convective rainfall during the afternoon, (ii) influence of Katabatic flows in the presence of rain during the early night, and (iii) nocturnal rain because of the influence of Mesoscale Convective Systems (MCS).