Korean Journal of Soil Science and Fertilizer ISSN:0367-6315(Print) 2288-2162(Online) 한국토양비료학회 학회지

In order to analyze drought, it is necessary to define and quantify drought intensity. Various drought indices have been proposed depending on purposes, but multiple time steps of Drought Indices make it hard to decide that which time step is the best to show the drought condition. This study aims to compare the drought results evaluated by the meteorological and agricultural drought standard. SPEI (standardized precipitation evapotranspiration index), SPI (standardized precipitation index), AWC (soil available water content) were calculated in three cities, and drought assessment results were compared. The characteristics of drought occurrence time, duration, intensity and tendency were analyzed by time series. It was found that the SPEI had the advantage to detect the starting of drought resulting from meteorological drought such as cumulative shortage of rainfall, while the results obtained from AWC had the advantage to detect the stage of drought resulting from agricultural drought. This study also proposed standard for time unit of drought index by comparing of estimated soil available water content results. The SPEI in 4-week unit could be selected as the meteorological drought index, which is judged to be suitable for comparing the time and depth of agricultural drought in Korea. We suggest that AWC based on the soil moisture deficit and SPEI-4 can be used for the drought monitoring and management. SPEI can be applied to detect meteorological drought earlier than Agricultural drought event.

Comparison of drought assessment results using SPEI and AWC for 2015 to 2016 in Boryeong. SPEI-4 adequately matched the drought characteristics of AWC.