Agro-climate changes over Northeast Asia in RCP scenarios simulated by WRF

摘要

Dynamically downscaled agro-climates for present (1981-2010) and future (2071-2100) climates under Representative Concentration Pathways (Historical, RCP4.5, and RCP8.5) in Northeast Asia (118 degrees-138 degrees E, 30 degrees-45 degrees N) are analysed in terms of the indices, such as vegetable and crop periods, frost days, and the climatic yield potential (CYP) for Japonica type rice (hereafter, rice). The model employed for dynamical downscaling is the Weather Research and Forecasting (WRF), with a 12.5-km horizontal grid spacing in the domain. According to our results, the CYP for rice, one of the major crops presently cultivated in the area, is expected to decrease throughout most of the region, despite a projected expansion of both vegetable and crop periods. This is projected to occur particularly in South Korea, Japan, and Southeast and Northeast China. Such a change is related to the projected rise in temperature within these regions, which will exceed the grain-filling optimum temperature of rice. In contrast, the climate projection of the RCPs is that the CYP will increase over northeastern parts of the Korean Peninsula and the Russian Far Eastern region (Primorsky), because temperatures in these regions are expected to rise and approach the grain-filling optimum temperature. For the RCPs, the optimum heading date, on which the domain averaged CYP is the highest, is expected to be later than that of the Historical by approximately 17-24 days. In addition, the maximum CYP in the RCPs is projected to decrease compared with that of the historical, and the possible period of rice ripening (period in which the CYP is greater than 0) is also expected to decrease.