三江源地区气候变化特征及其影响评估

Characteristics of Climate Change and Its Impact Assessment in the Three-River Regions

利用三江源区1961-2020年逐日气象数据、2006-2020年EOS/MODS监测资料,基于概率密度分布函数、线性趋势分析等方法,分析了气温、降水、极端气候指数变化趋势。结果表明:(1)1961-2020年三江源区气温明显向高温方向漂移,年平均、最高和最低气温升温率分别为0.38℃·(10a)^(-1)、0.28℃·(10a)^(-1)和0.45℃·(10a)^(-1)(P<0.01),最高和最低气温升温幅度存在不对称现象。同时极端气温暖事件(暖昼日数、暖夜日数)明显增多,极端气温冷事件(冷昼日数、冷夜日数)迅速减少。(2)与前一气候态(1961-1990年)相比,1991-2020年平均、最高和最低气温分别上升了1.28℃、1.12℃和1.60℃,且概率密度分布更加扁平,说明气温离散程度更大,气候不稳定性增强。(3)近60年来,三江源区降水量总体呈增多趋势,增加率为10.3 mm·(10a)^(-1),且随着降水量级的增加,降水量变化趋势越来越明显。进入21世纪以来,降水增多趋强表现更加明显。(4)在气温显著升高、降水量增多影响下,与第二次冰川编目相比,2019-2020年格拉丹东冰川和阿尼玛卿冰川面积分别减少5.51%和4.96%,冰储量分别减少23.43%和4.39%;三江源区年最大冻土活动层深度迅速减小,变化率为7.1 cm·(10a)^(-1),冻结期平均每10年缩短12.0天;积雪日数和累计积雪面积增多。受冰川冻土融水和降水量增多等因素的影响,三江源区湖泊面积总体呈增大趋势。

Based on the daily meteorological data from 1961 to 2020 and the EOS/mods monitoring data from 2006 to 2020 in the Three-River Regions,the variation trend of temperature,precipitation and extreme climate index was analyzed by using the probability density distribution function and linear trend analysis.The results show that:(1)the temperature drifts to high temperature from 1961 to 2020,and the warming rates of the annu‐ally average,maximum and minimum temperature was 0.38℃,0.28℃and 0.45℃per 10 years respectively(P<0.01).Accordingly the extreme temperature indices(warm days,warm night days)increased significantly,and the extreme temperature indices(cold days,cold night days)decreased rapidly.(2)Compared with the pre‐vious climate state(1961-1990),the annual average,maximum and minimum temperatures increased by 1.28℃,1.12℃and 1.60℃respectively from 1991 to 2020,and the probability density distribution was more flat,indicating that the temperature dispersion was greater and the climate instability was enhanced.(3)In the past 60 years,the precipitation has not increased significantly,with a change rate of 10.3 mm per 10 years.However,with the increase of precipitation,the change trend of precipitation is more and more obvious.Enter‐ing the 21st century,the increase of precipitation is more obvious.(4)Under the influence of significant temper‐ature rise and precipitation increase,compared with the second glacier inventory,the area of Gladandon glacier and Animaqing glacier will be reduced by 5.51%and 4.96%respectively,and the ice storage will be reduced by 23.43%and 4.39%respectively from 2019 to 2020;The annual maximum depth of frozen soil decreases rapidly with a change rate of 7.1cm per 10 years,and the average freezing period shortens by 12.0 days per 10 years;The number of snow days and accumulated snow area increased.The lake area shows an increasing trend due to the increase of glacial water and precipitation.