中国夏季极端气温与降水事件日数随平均气温变化的定量分析

Quantitative Analysis of Changes of Summer Extremes Temperature and Precipitation Days over China with Respect to the Mean Temperature Increase

极端高温、极端低温、极端降水事件日数对全球平均气温变化都有较强响应。本文利用全国1960-2005年549个站点逐日均一化温度资料以及559个站点逐日降水数据,定量分析了中国夏季极端气温与降水事件日数随气温变化的特征。结果表明:全球平均气温升高1℃,全国平均的极端高温、低温和降水日数的变化量分别为5.69,-5.3和0.69天;区域尺度上,全球平均气温升高1℃,东南沿岸和四川地区极端高温日数可增加8~10天,东北地区极端低温日数减少10天左右,西北地区极端降水日数可增加4~6天。基于以上结果,利用模式对未来全球平均气温的预估表明:2006-2099年我国平均的极端高温、低温、降水日数变化量在RCP8.5情景下最大,分别增加23天、减少22天和增加3天;区域尺度上,RCP8.5情景下2006-2099年我国东南以及西南地区极端高温日数可增加42天左右,我国北方大部分地区极端低温日数减少33天左右,而西北地区极端降水日数可增加16天左右。该研究结果表明一系列应对气候变化的措施势在必行。

The frequency of extreme high temperature,extreme low temperature and extreme precipitation are to a large extent the response to the global mean temperature.Using the Homogeneous temperature data at 549 sta‐tions and precipitation data at 559 stations over China,the changes of summer extremes temperature and precipi‐tation days over China with respect to the mean temperature increase are quantitative analyzed.Results show that:The national average changes of extreme high temperature,extreme low temperature and extreme precipita‐tion days are 5.69,-5.3 and 0.69 days for every Celsius degree increase of the global mean temperature;From regional aspect,for every Celsius degree increase of the global mean temperature,the extreme high temperature days increased 8~10 days in southeastern China and Sichuan province,the extreme low temperature days de‐creased 10 days in northeastern China,and the number of days of extreme precipitation in the northwest of China has the greatest increase that reaches 4~6 days.Based on above results,using projected global mean temperature from five global coupled climate models,the amount of variation of these climate extremes is largest under RCP8.5(Representative Concentration Pathways 8.5)scenarios.Under RCP8.5 scenarios,the national aver‐age of the number of days of extreme high temperature,extreme low temperature and extreme precipitation in China will increase 23 days,decrease 22 days and increase 3 days respectively in the next 100 years.As to re‐gion,the number of days of extreme high temperature will increase 42 days in the south of China,the number of days of extreme low temperature will decrease 33 days in the north of China and the number of days of extreme precipitation will increase 16 days in the northwest of China under RCP8.5 scenarios in the next 100 years.The above results suggest that a series of measures tackling climate change are imperative.