Teoría de valores extremos para el análisis de la precipitación de la estación meteorológica ESPOCH (1976-2019)

Abstract

The objective of the research was to analyze the probability distribution of extreme values, variability and behavior. For the study, the meteorological records of the ESPOCH station (Escuela Superior Politécnica de Chimborazo) were used, these data were analyzed and validated considering the thresholds established by the Alternative Energies and Environment Group (AEEG), the analysis was made, by means of the technique of extreme value theory. Precipitation is a phenomenon that has been characterized by its great space-time variability. The Ecuadorian Andes have extreme variation in their distribution. Previous research indicates that Chimborazo has shown a progressive predisposition for the last decades. For Riobamba, it was performed the study of variability of precipitation during 44 years, that is, from 1976 to 2019. Missing data and the absence of inconsistent data were found in the database. Time series was used and it was evidenced that at 7:00 there is a higher level of rain, followed by 19:00, with an average of 1.06 mm and 0.57 mm respectively, a variance of 14.63 mm, which indicated that there is a large variability during the 44 years of study. To know the distribution, the theory of extreme values with a maximum threshold of 0.1mm was used, by means of the Generalized Pareto Distribution (GPD) it was identified that extreme events conform to a Power Law and, finally, it was predicted by interpolation of data, the level of precipitation for the months of February and April obtaining 1.9 mm and 2.45 mm, in this way it is concluded that the probability of occurrence of extreme events is high. Thus, the level of precipitation has increased by 4 mm per decade. It is recommended to carry out more research oriented in this line, since there are very few in the country.