Drought assessment with the community land model for 1951-2010 in East Asia

Severe droughts have occurred in East Asia; however, observational hydroclimate data that covers the entire region is lacking. The objective of this study is to investigate drought assessment in East Asia. This study estimated three drought indices by generating hydroclimate variables using the Community Land Model (CLM). The results of the CLM were verified by comparison with Climatic Research Unit (CRU) data for precipitation and air temperature and the Global RunoffData Centre (GRDC) data for runoff. Spatial and temporal variations in three drought severity indices, including the standardized precipitation evapotranspiration index (SPEI), the standardized runoffindex (SRI), and the Standardized Soil Moisture Index (SSMI), in East Asia were estimated using the CLM output and compared with the SPEI in the CRU. This study classified drought frequency into four classes depending on the drought severity with 5-deg gapped longitude and latitude for 1951-2010 in East Asia and found that moderately dry (D2) and severely dry (D3) drought frequency classes matched well between the CLM and CRU data. The SPEI in the CLM and CRU data showed very similar frequency magnitudes and an increasing temporal trend. The SRI and SSMI frequencies for CLM also showed an increasing temporal trend compared to the SPEI frequency trend. The results of this study show that CLM outputs are reliable for drought analysis in East Asia. Furthermore, this study suggests the possibility of CLM application to other regions to generate hydroclimate data that is otherwise insufficient.