1.5和2℃升温阈值下中国温度和降水变化的预估

Projection of temperature and precipitation changes over China under global warming of 1.5 and 2℃

  • 摘要: 基于CMIP5耦合气候模式模拟结果对1.5和2℃升温阈值时中国温度和降水变化的分析表明,1.5℃升温阈值时,中国年平均升温由南向北加强且在青藏高原地区有所放大,季节尺度上升温的空间分布与其类似,就区域平均而言,RCP2.6、RCP4.5和RCP8.5情景下中国年平均气温分别升高1.83、1.75和1.88℃,气温的季节变幅以冬季升高最为显著;除华南和西南地区外中国大部分地区年平均降水量增多,降水的季节差异明显,以夏季降水的分布模态与年平均降水量的分布最为相似,区域平均的年降水量分别增加5.03%、2.82%和3.27%,季节尺度上以冬季降水增幅最大。2℃升温阈值时,RCP4.5和RCP8.5情景下中国年平均温度的空间分布与1.5℃升温阈值基本一致,中国年平均气温分别升高2.49和2.54℃,季节尺度上气温的变化以秋、冬季增幅最大;中国范围内年平均降水量基本表现为增多趋势,其中,西北和长江中下游部分地区表现为明显的季节差异,区域平均的年降水量分别增加6.26%和5.86%。与1.5℃升温阈值相比较,2℃升温阈值时中国年平均温度在RCP4.5和RCP8.5情景下分别升高0.74和0.76℃,降水则分别增加3.44%和2.59%,空间上温度升高以东北、西北和青藏高原最为显著,降水则在东北、华北、青藏高原和华南地区增加最为明显。

     

    Abstract: Based on the outputs of CMIP5 under three Representative Concentration Pathways (RCPs) scenarios, temperature and precipitation changes over China in the context of global warming of 1.5 and 2℃ are projected and their differences are further compared. The results show that in the context of global warming of 1.5℃ (relative to the reference period 1986-2005, the same hereafter), amplitudes of annual and seasonal mean temperature warming enhance towards high-latitude region especially in the Qinghai-Tibet Plateau. Annual mean air temperature over China will increase 1.83, 1.75 and 1.88℃ respectively under the RCP2.6, RCP4.5 and RCP8.5 scenarios with largest increases in the winter. Except for South China and Southwest China, most areas of China will experience more precipitation but the increase will be different between various seasons. The enhancement in annual mean precipitation over China ranges from 2.82% to 5.03%, and the largest increase occurs in the winter. The spatial distributions of temperature change are similar under the conditions of 1.5 and 2℃ global warming. When global warming is 2℃, annual temperature over China will increase 2.49 and 2.54℃ under the RCP4.5 and RCP8.5 scenarios, respectively. Annual precipitation will increase in most areas of China, whereas there are obvious seasonal differences in Northwest China and the middle and lower reaches of Yangtze River. Compared with the situation under the 1.5℃ threshold, more temperature and precipitation increases can be expected under the 2℃ threshold. The most significant increases in temperature will occur in Northeast China, Northwest China and the Qinghai-Tibet Plateau, while significant precipitation changes will occur in Northeast China, North China, the Qinghai-Tibet Plateau and South China.

     

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