ABSTRACT

Droughts are mainly caused by rainfall deficiencies and high evapotranspiration rates. This article introduces a Factual Drought Index (FDI) as a composite index, based on precipitation and potential evapotranspiration (PET). Its innovation lies in the fact that it does not consider the total PET, but only the amount of PET that exceeds or falls behind the corresponding average PET, for a certain time period. So far, the PET-based indices take into account the total amount of PET, which in semiarid areas, may lead to overestimation of drought events. FDI was tested in drought-prone Greece, for the year 1990, when the country experienced an extreme drought event, and its results were compared to the corresponding Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). FDI constitutes a useful drought-management tool, as it satisfactorily identifies and categorizes drought events and is sensitive to precipitation and evapotranspiration changes.

摘要

干旱主要由降雨不足和高蒸散率引起。本文介绍了一种基于降水和潜在蒸散量 (PET) 的综合指数，即实际干旱指数 (FDI)。它的创新之处在于它不考虑PET总量，而只考虑在一定时间段内超过或落后于相应平均PET的PET数量。迄今为止，基于 PET 的指数考虑了 PET 的总量，这在半干旱地区可能会导致对干旱事件的高估。1990 年，在易受干旱的希腊，FDI 进行了测试，当时该国经历了极端干旱事件，并将其结果与相应的标准化降水指数 (SPI) 和标准化降水蒸散指数 (SPEI) 进行了比较。