基于CMIP5多模式集合资料的中国气温和降水预估及概率分析

Probability Assessment of Temperature and Precipitation over China by CMIP5 Multi-Model Ensemble

选用国际耦合模式比较计划第五阶段(CMIP5)提供的30个全球大气-海洋耦合模式(AOGCMs)在典型浓度路径(RCPs)情景下气温和降水量的预估结果,采用扰动法,用站点观测资料作为气候背景场替代AOGCM模拟的气候平均,尝试校正气候预估结果的系统性偏差。通过集合方法,用概率的形式给出中国平均气温升高1℃、2℃和3℃以及降水量增加10%、20%和30%概率的空间分布,讨论了中国未来平均气温和降水量可能的变化。结果表明:经过扰动法处理后的气温和降水量预估集合保留了当前气候的局地信息。预估平均气温在中国均有上升,北方地区尤其是青藏高原地区变暖的程度大于南方地区,北方大部分地区平均气温升高的趋势为0.28℃/10a。在21世纪初,中国北方地区年平均气温升高1℃的可能性超过50%。到了21世纪末期,中国大部分地区平均气温升高2℃的可能性超过60%,新疆北部以及青藏高原南部地区气温升高3℃的可能性超过50%。预估中国降水量普遍增多,中国北方地区降水量增多的程度要明显大于江淮流域及其以南地区,尤其是西北地区降水量增多非常显著,降水量增多30%的可能性超过70%以上。

By applying climate projections based on 30 Atmosphere-Ocean General Circulation Models(AOGCMs)under representative concentration pathway(RCP)scenarios in the Coupled Model Inter-comparison Project Phase 5(CMIP5),we assess temperature and precipitation over China in terms of ensemble method.However,significant uncertainties exist among the AOGCM outputs.In this paper,apseudo global warming(PGW)method is assumed to be a linear coupling of contemporary climatic fields and the difference component of climate perturbation signals by AOGCMs.Surface temperature rise of 1℃,2℃,and3℃and precipitation increase 10%,20%and 30%above the present level are assessed and a probabilistic approach is used to address the uncertainties.The results show that the ensembles of data are obtained through the PGW method,which efficiently reserves the contemporary climatic information.Warming is expected in all regions of China,with the northern China regions showing greater warming than the southern China regions, especially Tibet region.The increase linear trend of temperature is 0.28 ℃/10a in most parts of northern China.Projected temperature would raise 1℃ with above 50%in northern China at the start of 21 century. In the end of 21 century,surface temperature would exceed 2.0℃ with more than a probability of 60%in all regions of China.The northern Xinjiang and the southern Tibet would above 50% with a 3℃ warming. Projected precipitation would increase,and the increasing precipitation in the northern regions would more significant than in the southern China regions.The projected precipitation would increase more than 30% with a probability of 70%in China.