两种不同减排情景下21世纪气候变化的数值模拟

利用国家气候中心最新发展的气候系统模式BCC-CSM1.0模拟了相对于B1排放情景,两种不同减排情景(De90和De07,表示按照B1情景排放到2012年,之后线性递减,至2050年时CO_2排放水平分别达到1990和2007年排放水平一半的情景)对全球和中国区域气候变化的影响.结果表明:两种减排情景下模式模拟的全球平均地表气温在21世纪40年代以后明显低于Bl情景,比减排情景浓度低于B1的时间延迟了20年左右;尽管De90减排情景在2050年所达到的稳定排放水平低于De07情景,但De90情景下的全球增温在2070年以后才一致低于De07情景,这种滞后町能与耦合系统(主要足海洋)的惯性有关;至21世纪末,De90和De07情景下的全球增温幅度分别比B1情景降低了0.4和0.2℃;从全球分布来看,B1情景下21世纪后30年的增温幅度在北半球高纬度和极地地区最大,减排情景能够显著减少这些地区的增温幅度,减排程度越大,则减少越多;在中国区域,B1情景下21世纪末平均增温比全球平均高约1.2℃,减排情景De90和De07分别比B1情景降低了0.4和0.3℃,中国北方地区增温幅度高于南方及沿海地区,减排情景能够显著减小中国西部地区的增温幅度;B1情景下21世纪后30年伞球增温在冬季最高,De90和De07情景分别能够降低各个季节全球升温幅度的17%和10%左右.

Numerical simulation of climate change in 21 century under two different mitigation scenarios.

The climate system model BCC- CSM1.0, newly developed by National Climate Center, is used to simulate climate influences of two mitigation scenarios (De90 and DeO7) on global and China climate compared to the B1 emissions scenario. The mitigation scenarios De90 and De07 represent CO_2 emissions are linearly decreased during 2012-2050, and mitigated to half of that in 1990 and 2007 by 2050, respectively. Results show that the global mean surface air temperature simulated by the model under the two mitigation scenarios has been lower than that under the Bl scenario since 2040s. This is twenty years later than when the concentrations of the mitigation scenarios are less than that of the Bl scenario. Although the stabilization emission level of De90 scenario is lower than De07 after 2050, the global warming amplitude under De90 scenario has been lower than that under De07 scenario since 2070. Such delay effect may be related to the inertia of the coupled system (mainly the ocean). By the end of 21 century, the warming amplitudes of De90 and De07 will be lowered by 0.4℃ and 0.2℃, respectively. Globally, the warming amplitude during 2070 -2099 under Bl scenario will be the largest in the high amplitudes of the North Hemisphere and the North Pole. The mitigation scenarios significantly mitigate the warming in those regions. In China, regional mean warming amplitude by the end of 21 century will be higher than the global mean by about 1.2℃. This will be lowered by De90 and De07 scenario about 0.4℃ and 0.3℃ , respectively. Northern China will be warmer than that in southern China and the southern coasts during 2070-2099. The mitigation emission scenarios significantly decrease the warming amplitude in western China. Seasonally, the global warming during 2070-2099 will be the largest in winter. De90 and De07 can mitigate the warming in each season by about 17% and 10% , respectively.