基于时空分异的中国1961—2018年不同极端气温指数演变特征

为诊断变化环境下中国极端气温事件的动态演变特征,基于中国气象局国家气象信息中心的《中国地面气象要素年值数据集》的545个气象站点观测数据,考虑平均气温、气温年较差、极端最高气温和极端最低气温4项指标,采用距平分析、线性趋势、变异系数等多种统计方法,从多属性角度诊断1961—2018年中国极端气温指数时空分异特征。结果表明:(1)在气候态上,1961—2018年中国不同极端气温指数表现出多种时空分异特征,首先是纬度主导下的南北分异,其次是经度主导下的东西分异,最后是海拔主导下的高低分异。(2)在年代距平上,中国平均气温距平随年代发展逐渐由负距平为主演变为以正距平为主。气温年较差距平在东西地区具有年代差异特征。极端最高气温距平在西藏地区演变特征与平均气温距平相一致。极端最低气温距平在1960年代和1970年代以负距平为主,而在1980—2010年代以正距平为主,且具有东西和南北分异特征。(3)在变化趋势上,中国平均气温和极端最低气温在1961—2018年均以增加趋势为主,且多数地区增加趋势速率分别超过了0.8℃/10 a和0.4℃/10 a。气温年较差和极端最高气温在西藏地区以减少趋势为主,且多数地区的减少趋势速率超过了0.4℃/10 a。中国整体趋于增暖的背景下,东部地区的高温事件在区域增多增强。(4)在年际变异上,1961—2018年中国平均气温年际变异最大,极端最低气温次之,气温年较差再次之,极端最高气温最小。上述结果表明中国气温在朝着极端化方向发展,需要高度关注极端气温事件风险及其引发的工程灾害事件。

Spatial-temporal differentiation-based evolution characteristics of different extreme air temperature indexes in China from 1961 to 2018

In order to diagnose the dynamic evolution characteristics of extreme air temperature events under changing environment in China,the spatial-temporal differentiation of the different extreme air temperature indexes in China from 1961 to 2018 are diagnosed from multi-attribute aspects by means of several statistical methods,i. e. anomaly analysis,linear trend,coefficient of variation,etc. under the consideration of the four indexes of mean air temperature,annual air temperature range,extreme maximum air temperature and extreme minimum air temperature in accordance with the Data Set of Annual Value of Surface Meteorological Elements in China issued by National Meteorological Information Center of China Meteorological Administration. The result shows that ( 1) Climatologically,the different extreme air temperature indexes in China from 1961 to 2018 exhibit several spatialtemporal differentiation characteristics,i. e. at first,the latitude-dominated north-south differentiation,and then the latitude-dominated east-west differentiation,finally,the altitude-dominated high-low differentiation. ( 2) In the aspect of interdecadal anomaly,the mean air temperature anomaly in China gradually changed from negative anomaly to positive anomaly with the development of decades. The temperature annual range anomaly has the characteristics of chronological difference in the east and west regions in China. The evolution characteristics of the extreme maximum air temperature anomaly in Tibet are consistent with the mean air temperature anomaly. The extreme minimum air temperature anomaly is dominated by the negative anomaly in the 1960s and 1970s,while the positive anomaly is dominated in the 1980s to 2010s with the characteristics of east-west and north-south differentiations. ( 3) On the changing trend,the mean air temperatures and the extreme minimum air temperatures in China mainly increase from 1961 to 2018 and the increasing trends in most of the regions exceed 0. 8 ℃ /10 a and 0. 4 ℃ /10 a respectively. The air temperature annual range and the extreme maximum air temperature in Tibet are mainly dominated by decreasing trend and the decreasing trends in most of the regions exceed 0. 4 ℃ /10 a respectively. Under the background of overall warming in China,the high air temperature events in the eastern region are increasing and strengthening. ( 4) In terms of interannual variation,the annual variation of mean air temperature in China from 1961 to 2018 is the largest and follows with the extreme lowest air temperature,the air temperature annual range and the extreme highest air temperature in sequence. The above result shows that the temperature in China develops towards extremity,thus high attention is necessary to be paid to the risk of extreme air temperature event and the engineering disaster event caused by it.