Resumo

CAMPOS-ARANDA, Daniel F.. Comparison of three statistical methods for detection and monitoring of meteorological drought. Agrociencia [online]. 2014, vol.48, n.5, pp.463-476. ISSN 2521-9766.

Drought is a recurring natural phenomenon of regional character, whose negative effects can be lessened if they are detected timely and have an adequate monitoring. This paper describes in detail three effective statistical methods to detect meteorological droughts, which can also be used in monitoring. Such methods are probabilistic precipitation deficit, the standardized precipitation index and the drought reconnaissance index. The latter uses, in addition to rain, potential evapotranspiration, thus taking into account other variables associated with drought, as high temperatures. The three methods are applied to the record of 64 years (1949-2012) of monthly precipitation of the weather station Fresnillo in Zacatecas state, Mexico. Based on the numerical application it is concluded that the first method does not detect drought years, in similar way to the other two, because it takes into account implicitly the seasonal distribution of rainfall each year. The other two methods provide very similar results, both in the interpretation of the severity of annual droughts, as in establishing their periods of continuous or interleaved occurrence. Also it follows that the results of the three exposed methods complement each other to define more precisely the meteorological drought, according to their fixed duration and therefore their joint application is recommended for each weather station processed. Regional analysis of the available records will allow reaching conclusions about the spatial variation of drought.

Palavras-chave : Mixed Gamma distribution; statistical tests; standard error of fit; severity and duration of droughts; monthly ETP.

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