青藏高原三江源地区近60 a气候与极端气候变化特征分析

Changes of climate and climate extremes in the Three-Rivers Headwaters' Region over the Tibetan Plateau during the past 60 years

摘要:

青藏高原三江源地区正在面临着以"变暖变湿"为主的气候变化，是气候变化的显著区与敏感区。基于中国气象局位于三江源地区20个地面台站的气温、降水数据以及HadCRUT4（Climatic Research Unit land-surface air temperature-4 dataset and the Hadley Centre sea-surface temperature dataset，Hadley Centre，UK）气温、PREC（Precipitation Reconstruction，National Oceanic and Atmospheric Administration，USA）降水资料，从气候要素空间格局、极端气候指标以及区域-全球平均多年变化对比等3个方面系统总结了三江源地区1961-2019年气候和极端气候变化的特征。结果显示，三江源区域在过去近60 a里平均增暖速率为0.37℃/（10 a），是全球平均水平（0.16℃/（10 a））的2倍以上，同时大幅高于全球同纬度（0.19℃/（10 a））及中国区域（0.28℃/（10 a））。在全球变暖背景下，三江源地区大部分极端气候指标上升，其中以夜间最低气温的上升（0.55℃/（10 a））最为显著，且极端高温事件的出现频率上升，区域日温差减小、气温变化极端性增强。三江源近60 a温湿气候态的空间格局为沿西北-东南方向的正温湿梯度，其变化趋势存在自西向东速率上升的暖湿化空间分异特征。本文的研究结论进一步揭示了三江源地区近60 a气候变化与极端气候的时空格局，为三江源地区气候系统和生态系统的脆弱性研究以及未来气候变化预估提供了科学依据，同时也为气候变化敏感的高寒地区对全球变暖的响应研究提供了对比案例。

关键词:三江源地区|气候变化|极端气候|全球变暖

Abstract:

The Three Rivers Headwaters' Region is significant and sensitive to climate change,which is characterized with "warmth and wetness".From such perspectives as spatial pattern,climate extreme indices and comparison among regional-global climate variations,characteristics of climate variations and climate extremes in the Three Rivers' Headwaters Region over the Tibetan Plateau from 1961 to 2019 was studied.Temperature and precipitation observation data were obtained from 20 meteorological stations of China Meteorological Administration,HadCRUT4 as well as NOAA Precipitation Reconstruction datasets.It was revealed that the spatial averaged warming rate was 0.37℃/(10 a),which was more than the global average level (0.16℃/(10 a)) during the past 60 years and was also significantly higher than that in the same latitude (0.19℃/(10 a)) and in China (0.28℃/(10 a)).Under the background of global warming,most of the extreme climate indices in the Three Rivers' Headwaters Region have risen,and the most significant one is night extreme high temperature (0.55℃/(10 a)),suggesting the extremeness of regional climate has strengthened.The spatial pattern of temperature and precipitation during the past 60 years shows a positive gradient along the northwest-southeast direction,and its variation is characterized by a rising trend in the spatial differentiation of warming and humidification from west to east.Furthermore,the temporal-spatial patterns of climate change and climate extremes in the Three Rivers' Headwaters Region can provide some bases for research on the vulnerability of climate systems and ecosystems in this region.At the same time,this study also provides a comparative case for studies on the response of climate-sensitive alpine regions to global warming.

Key words:Three-Rivers Headwaters' Region|climate change|climate extremes|global warming