BCC_CSM1.1全球模式中极端气温变化的归因分析

Attribution Analysis of the Extreme Temperature Change in BCC_CSM1. 1 Global Pattern

利用1°×1°的ERA-Interim再分析资料和气候系统模式BCC_CSM1.1历史模拟(Historical)试验及气候归因试验(只考虑温室气体变化Historical GHG试验和只考虑自然强迫变化的Historical Nat试验)的结果,考查了BCC_CSM1.1模式对中国和全球陆地地区极端气温指数的模拟能力,并在此基础上分析了温室气体和自然强迫这两种外强迫的变化对极端气温变化的贡献。结果表明:BCC_CSM1.1可以对中国乃至全球陆地区域极端气温指数的气候态及其变化趋势进行合理模拟,主要偏差表现为模式对极端低温指数模拟值偏低,而对极端高温指数模拟值偏高。对于20世纪末极端气温指数的变化,只有考虑了温室气体变化的外强迫时,模式可以再现再分析资料中极端气温的变化趋势。这表明温室气体的变化对极端气温的变化有着关键性的影响。

Historical simulation and simulations for climate change detection and attribution studies （ only considering HistoricalGHG test of greenhouse gases change and only considering HistoricalNat test of natural forcing change） performed by BCC_CSM1.1 and ERA-Interim 1°×1° reanalysis data are em- ployed in this study. Firstly, the performance of the model to simulate temperature extreme over China and the globe land area is evaluated, and then, the contributions of greenhouse gas forcing and natural forcing to the change in temperature extremes are investigated. The results show that BCC_CSM1. 1 could reasonably simulate the spatial distribution of the climatology and trend of temperature extreme indexes o- ver China and the globe land area. The main deficiency is that the model underestimates the cold extreme indexes while overestimates the warm extreme indexes. At the end of 20th century, the model could re- produce the trend in temperature extreme indexes only if the change of greenhouse gas forcing is includ- ed, which implies that the change of greenhouse house gas forcing is the key factor to the change of tem- perature extremes.