The change of cherry first-flowering date over South Korea projected from downscaled IPCC AR5 simulation

摘要

Simulations from six global climate models participating in Coupled Model Intercomparison Project 5 are used to project future changes in regional early spring (February-April) temperature and in cherry (Prunus yedoensis) firstflowering date (FFD) over South Korea in order to investigate a potential plant growth response to local climate change. For the study, we statistically downscale daily Historical (1986-2005), RCP4.5 (2071-2090), and RCP8.5 (2071-2090) gridded model data to 59 cherry FFD observation sites over South Korea. In order to reduce the uncertainties in the model simulation produced by a single model, multi-model ensemble (MME) is performed after eliminating the mean systematic bias of each model. A shift of cherry FFD under global warming is estimated and compared with the observation and Historical simulation by applying the downscaled data to a DTS phenological model. The analysis reveals a projected advance in cherry FFD over South Korea by 2090 of 6.3 and 11.2 days compared to the current dates due to a rising mean temperature of about 2.0 and 3.5K under the RCP4.5 and RCP8.5 scenarios, which approximately correspond to moving north at a speed of 0.01 and 0.03oNyear~(?1), respectively. These average yearly advances (0.07 and 0.13 days year~(?1)) of cherry FFD in the RCP4.5 and RCP8.5 simulations are 0.22 and 0.16 days year~(?1) lower, respectively, than the value of 0.29 days year~(?1) derived in previous studies with the SRES A2 scenario. Regardless of the difference between the SRES A2 and RCP8.5 scenarios, the discrepancy in the advancement tendency was primarily attributed to the inability of the previous studies to eliminate the systematic model biases, which led to overestimation of both the temperature and the FFD changes.