Application of evaporative demand drought index (EDDI) in drought identification of Liaoning Province, China

Abstract

The evaporative demand drought index (EDDI) is a multi-scale drought index developed from the atmospheric evaporation demand (E0). EDDI is independent of precipitation and suitable to different underlying surfaces, which can well capture water stress signals at different time scales. Based on the meteorological observation data at 52 stations in Liaoning Province from 1961 to 2018, we estimated daily E0, calculated EDDI at six time scales (annual, growing season, spring, summer, autumn and winter), and further identified the interannual variability of drought occurrence in Liaoning Province for the past 58 years. The results showed that EDDI had obvious interannual variation, with two high concentration periods in multiple time scales. In the 1960s, when there were many years and serious drought in Liaoning Province, high EDDI values were concentrated at the five time scales (annual, growing season, spring, autumn and winter). 2014-2018 was another relatively concentrated period of EDDI high value at all time scales except winter. In 1981-1982, the values of EDDI were high at the time scales of the annual, growth season, summer and autumn. The periods of 1963-1965 (except summer), 1972-1973 (growth season, summer), 1989-1990 (annual, growth season, spring and winter), 1997-1998 (annual, growth season and summer), 2004-2005 (spring and winter) and 2013-2014 (annual, growth season and autumn) occurred abrupt alternation from dry to wet or from wet to dry. In 1985-1987, 1993-1995 and 2005-2013, Liaoning Province had obvious dry gaps.