Resumen

CAMPOS-ARANDA, Daniel Francisco. Estimation of severity of environmental droughts through monthly rainfall records. Tecnol. cienc. agua [online]. 2012, vol.3, n.1, pp.123-130. ISSN 2007-2422.

This work defines droughts and cites their more common indicators, as well as presents a classification for environmental droughts and water supply droughts. For environmental droughts, a simple system is proposed to define their severity and duration. To identify drought years, the use of monthly rainfall records is suggested, completing missing monthly data with their mode. The procedure is aimed at obtaining the monthly medians and then the differences between each rainfall and its median. The sum of the negative differences for each year defines the annual rainfall deficit, which is a numerical indicator of its anomalous behavior. The probabilistic analysis of annual deficits using several models-selecting the one with the minimum standard error of fitting-allows for finding the limits associated with return periods of 5, 20 and 50 years, which define the years with moderate, strong and severe droughts. The suggested procedure was applied to 123 years of records available from the meteorological observatory in San Luis Potosi. The results of this study agree with the conclusions of previous studies.

Palabras llave : droughts; monthly rainfall; mode; medians; probabilistic models.