关键词: 统计降尺度, 数据订正, RCP4.5和RCP 8.5情景, 气候生产潜力

Abstract:

A bias correction model for simulated climate data was constructed. The nonlinear transfer function between simulations and observations and the parameters for variation correction were determined based on historical simulations outputting from a regional climate model RegCM4 coupled with a global model BCC_CSM1.1 (Beijing Climate Center Climate System Model version 1.1) and the observations during baseline period from 1961-1990. The effectiveness of bias correction model was verified using simulated climate data and observed data during validation period from 1991-2005. This model was then used to correct climate data under RCP (Representative Concentration Pathway) scenarios during future period from 2021-2050. Meanwhile, the spatial patterns of winter wheat climatic potential productivity of Jiangsu were projected via productivity decay method under future scenario climates. The results indicated that it was effective to apply bias correction method for simulated climate data in projection of crop climatic potential productivity. The bias correction model with mean value and variation information was an excellent way of correcting simulated climate data at daily scale in Jiangsu. The bias of simulated temperature, radiation, evapotranspiration in autumn and winter as well as precipitation in winter and spring was reduced obviously after correction. Then, on the basis of bias correction, the maturity date of winter wheat in Jiangsu was projected between 153-175 and 153-174 respectively under RCP4.5 and RCP8.5 scenarios, and would advance obviously compared with baseline. The estimated climatic potential productivity of winter wheat was projected between 10335-14368kg·ha^-1 and 9991-13708kg·ha^-1 respectively, and would tend to be lower than that during baseline period. Accordingly, the coefficient of variation of climatic potential productivity was projected between 7.6%-14.6% and 7.5%-13.6% respectively, and would increase compared with baseline, which indicated a tendency towards unstable for climatic potential productivity of winter wheat in Jiangsu. Moreover, during future period, the climatic potential productivity of winter wheat would remain relatively high (≥12501kg·ha^-1) in central and northern Xuzhou, northeastern Lianyungang, western Suqian and southeastern Yancheng under RCP4.5 and RCP8.5 scenarios. Thus, the cultivated land for winter wheat in these regions should be guaranteed by the government of Jiangsu. Our results suggested a consideration of bias correction for simulated climate data using observations of study region before estimating crop climatic potential productivity, in order to enhance the credibility of the projections.

Key words: Statistical downscaling, Data correction, RCP4.5 and RCP8.5 scenarios, Climatic potential productivity