基于综合视角的近55 a青藏高原气温变化分析

Comprehensive analysis of temperature variations over the Qinghai-Tibet Plateau from 1961 to 2015

基于青藏高原73个气象站点1961-2015年的逐日最高气温、最低气温和日平均气温资料,从趋势、波动特征和极端事件3个维度,利用最小二乘回归分析、Mann-Kendall突变检验及Pearson相关分析等方法全面剖析该地区近55 a气温的趋势变化、波动变化与极端事件变化.结果表明,时间上,1961-2015年青藏高原气温暖化特征明显,变化速率表现为年内日最高气温<年均气温<年内日最低气温、结冰日数<霜冻日数;突变时间表现为日最低气温<霜冻日数<年均气温<日最高气温<结冰日数.气温变化呈不对称性,最低气温的变化比年均气温和最高气温的变化更加敏感.空间上,滇西北地区气温升温迅速,波动快速增强;柴达木盆地、"一江两河"地区、川西高原呈气温缓慢升高-波动快速增强或气温快速升高-波动缓慢增强特征;那曲高原、黄河源区气温升高迅速同时伴随波动减弱,升温趋势稳定.青藏高原不同地区暖化主导因素不同,日最高气温的持续上升是高原东北部气候暖化的主导因素;日最低气温的持续上升对高原南部气候暖化的贡献更明显;而柴达木盆地则受到日最高、最低气温剧烈变化的双重影响.年均气温的变化与日最高、最低气温的变化呈正相关关系,与结冰日数和霜冻日数的变化呈负相关关系.年均气温的变化与极端事件的变化在一定程度上可以相互指示.

Based on the daily maximum,minimum and averaged temperature data from 73 meteorological stations on the Qinghai-Tibet Plateau during 1961-2015,temperature variations were comprehensively analyzed by using the least-squares regression analysis,Mann-Kendall test and Pearson correlation analysis from new perspectives of the combinations of trends,fluctuation characteristics and extreme events.The results showed that the increment of temperature was extraordinarily obvious during 1961-2015 and,as for the rates of the regional-averaged change,the maximum temperature(0.31℃/10 a)<the averaged temperature(0.33℃/10 a)<the minimum temperature(0.52℃/10 a),and the number of ice days(-2.79 d/10 a)<the number of frost days(-4.53 d/10 a).The changes in the minimum temperature were more sensitive than those in the averaged and maximum temperature.Spatially,the temperature in Northwest Yunnan elevated rapidly and the fluctuations were enhanced fleetly.The drastic increment of temperature did not occur together with a fleet enhancement of temperature fluctuations in the Qaidam Basin,the Yarlung Zangbo River,Nyangqu River,Lhasa River regions and Western Sichuan Plateau.And in the Naqu Plateau and the source regions of the Yellow River,the temperature elevated rapidly and the fluctuations weakened,and the increment was stable.There had been different dominant factors of the warming in different areas.The continuous rise of the maximum temperature was the leading factor in the Northeast Plateau and the rise of the minimum temperature contributed more to the warming in the Southern Plateau.Distinctively,the Qaidam Basin was affected by the maximum and minimum temperature changes.The variations on the annual averaged temperature were significantly positively correlated with the variations on the maximum temperature and the minimum temperature,and were significantly negatively correlated with the variations on the ice and frost days.To some extent,variations on the annual averaged temperature and on the extreme events could be mutually indicative.