Evaporative Stress Index (ESI)의 국내 가뭄 심도 분류 기준 제시

초록

Drought is considered as a devastating hazard that causes serious agricultural, ecological and socio-economic impacts worldwide. Fundamentally, thedrought can be defined as temporarily different levels of inadequate precipitation, soil moisture, and water supply relative to the long-term averageconditions. From no unified definition of droughts, droughts have been divided into different severity level, i.e., moderate drought, severe drought,extreme drought and exceptional drought. The drought severity classification defined the ranges for each indicator for each dryness level. Becausethe ranges of the various indicators often don’t coincide, the final drought category tends to be based on what the majority of the indicators showand on local observations. Evaporative Stress Index (ESI), a satellite-based drought index using the ratio of potential and actual evaporation, is beingused as a index of the droughts occurring rapidly in a short period of time from studies showing a more sensitive and fast response to droughtcompared to Standardized Precipitation Index (SPI), and Palmer Drought Severity Index (PDSI). However, ESI is difficult to provide an objectivedrought assessment because it does not have clear drought severity classification criteria. In this study, U.S. Drought Monitor (USDM), the standardfor drought determination used in the United States, was applied to ESI, and the Percentile method was used to classify drought categories by severity. Regarding the actual 2017 drought event in South Korea, we compare the spatial distribution of drought area and understand the USDM-based ESIby comparing the results of Standardized Groundwater level Index (SGI) and drought impact information. These results demonstrated that theUSDM-based ESI could be an effective tool to provide objective drought conditions to inform management decisions for drought policy.

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