1.5℃温控目标下气候工程对中国极端高温强度影响的空间差异研究

全球变暖背景下极端高温热浪频发,已成为严重影响人类健康和社会可持续发展的气象灾害之一。基于BNU-ESM模式的气候工程(G4试验)和非气候工程(RCP4.5)情景下的2020～2099年日值最高气温数据和平均气温数据,采用韦伯分布理论,对比分析了气候工程实施中(2020～2069年)和实施结束后(2070～2099年)的中国极端高温强度区域差异特征。结果表明:(1)两种情景下的对比表明,气候工程并未从根本上改变中国不同重现期的极端高温强度空间高低分异特征。两种情景下的极端高温强度在两个时段均呈青藏高原低,东部和西北高的空间分异特征。(2)两种情景下的对比表明,气候工程在两个研究时段均有助于中国不同重现期极端高温强度的缓解,且实施期间的缓解作用明显高于结束后。(3)气候工程情景下2020～2069年与2070～2099年的对比结果表明,气候工程实施结束后并未引起极端高温的强烈反弹,且气候工程实施期间对极端高温强度的缓解作用明显高于结束后。(4)对比气候工程实施前后中国平均气温变化,结果表明气候工程使得中国平均气温至少降低了1.25℃,有效缓解了全球气候变暖,有利于《巴黎协定》1.5℃温控目标的实现。在当前1.5℃温控目标下,平均气温的降低有助于减少和缓解更多极端高温事件的频次与强度,深化气候工程对极端高温事件影响的认识。

Spatial Difference of Extreme High Temperature Intensity in China Under 1.5℃ Temperature Control Target

Under the background of global warming, extreme high temperature and heat waves occur frequently, which has become one of the meteorological disasters seriously affecting human health and social sustainable development. Based on the daily maximum temperature and average temperature datasets of from 2020 to 2099 in climate engineering (G4 test) and non-climate engineering (RCP4.5) scenarios of BNU-ESM model, the extreme high temperature intensity regions difference characteristics in China during and after the implementation of climate engineering (2020-2069) are analyzed by Weibull extreme value distribution theory. The results show that: Firstly, the comparison between the two scenarios shows that climate engineering has not fundamentally changed the spatial variability of extreme high temperature intensity in different return periods in China. In both scenarios, the extreme high temperature intensity is characterized by the spatial differentiation of low in the Qinghai-Tibet Plateau and high in the East China and Northwest China. Secondly, the comparison between the two scenarios shows that climate engineering can help to mitigate the extreme high temperature intensity in different return periods in China, and the mitigation effect during the implementation period is significantly higher than that after the completion. Thirdly, the results of comparison between 2020-2069 and 2070-2099 under the climate engineering scenario show that there is no strong rebound of extreme high temperature after the implementation of climate engineering, and the mitigation effect of extreme high temperature intensity during the implementation of climate engineering is significantly higher than that after the completion. Fourthly, at the same time, comparing the changes of the average temperature in China during and after the implementation of climate engineering, the results show that the average temperature in China has been reduced by at least 1.25℃, which effectively alleviates global warming and is conducive to the realization of the Paris Accord temperature control target of 1.5℃. Under the current temperature control target of 1.5℃, the decrease of average temperature will help to reduce and mitigate the frequency and intensity of more extreme high temperature events, and deepen the understanding of the impact of climate engineering on extreme high temperature events.