Future projection of droughts over South Korea using Representative Concentration Pathways (RCPs)

Abstract

The Standardized Precipitation Index (SPI), a method widely used to analyze droughts related to climate change, does not consider variables related to temperature and is limited because it cannot consider changes in hydrological balance, such as evapotranspiration from climate change. If we were to consider only the future increase in precipitation from climate change, droughts may decrease. However, because usable water can diminish from an increase in evapotranspiration, it is important to research on projected droughts considering the amount of evapotranspiration along with projecting and evaluating potential droughts considering the impact of climate change. As such, this study evaluated the occurrence of droughts using the Standardized Precipitation Evapotranspiration Index (SPEI) as a newly conceptualized drought index that is similar to SPI but includes the temperature variability. We extracted simulated future precipitation and temperature data (2011-2099) from the Representative Concentration Pathway (RCP) climate change scenario of IPCC AR5 to evaluate the impact of future climate change on the occurrence of droughts of South Korea. We analyzed the ratio of evapotranspiration to precipitation of meteorological observatories nationwide. In addition, we calculated the SPEI related to drought in the process to evaluate the future occurrence of droughts of South Korea. To confirm validity of SPEI results, extreme indices were analyzed. This resulted in the notion that as we go further into the future, the precipitation increases. But because of an increase in evapotranspiration also from a rise in temperature and continued dryness, the severity of droughts is projected to exacerbate.