中国20年一遇气温和降水极值变化的高分辨率模拟

基于25 km高分辨率区域气候模式（RegCM3）嵌套MIROC3.2_hires全球气候模式结果，进行IPCC SRES A1B情景下21世纪气候变化的模拟，分析中国区域未来气温和降水极值重现期的变化。首先检验模式对当代（1981-2000年）极端事件重现期的模拟能力，结果表明，模式能够较好地再现中国地区20年一遇极端事件的基本分布型，但所模拟的数值与观测相比还有一定偏差，特别是在极端降水方面。21世纪中期（2041-2060年）和末期（2081-2100年）20年一遇的高温极值在整个区域内均将升高，东北地区增幅最大；低温极值将增大，中心位于内蒙古、新疆及青藏高原南麓；降水极值也将普遍增大。气温和降水极值在21世纪末期的增加幅度均比中期要大。在未来全球变暖背景下，中国地区极端高温事件将明显增多，面积增大；极端低温事件将大幅度减少，面积减少；强降水事件也将增多，面积不断扩大。

Changes of 20-Year Return Temperature and Precipitation Extremes over China Simulated by RegCM3

Based on a high resolution climate change simulation of the 21st century conducted by a regional climate model(RegCM3) nested with a global climate model(MIROC3.2_hires),temperature and precipitation extremes changes as measured by 20-year return values over China under the IPCC SRES A1B scenario are analyzed.Validation of the model performances in simulating present day(1981-2000) distribution of 20-year return values against the observation is firstly carried out.Results show that the model reproduced well the spatial distributions of the values.However,compared with the observation,the model showed deficiencies in simulating the magnitudes of them.Significant increase of the 20-year return values of extreme maximum temperature is found over the whole China in the model simulation,both in the middle(2041-2060) and end(2081-2100) of the 21st century,especially over the Northeast China in the end of the 21st century.Increased value for extreme minimum temperature in the future is also simulated,while the greatest increase is found over Inner Mongolia,Xinjiang and southern slope of the Tibetan Plateau.General increase of extreme precipitation value is also found both in the middle and end of the 21st century.The above changes are more profound in the end of the 21st century compared with the middle.The results indicate a general increase of the frequency and spread of heat waves,and a general decrease of the frequency and spread of extreme cold events in the future over China.Extreme precipitation events are also projected to increase in both the frequency and the spread.