Nonlinear response of Asian summer monsoon precipitation to emission reductions in South and East Asia
Nonlinear response of Asian summer monsoon precipitation to emission reductions in South and East Asia
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DOI：
10.1088/1748-9326/ac3b19
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发表时间：
2022-01-01
影响因子：
6.7
通讯作者：
Frame, Dave
中科院分区：
文献类型：
--
作者：
Herbert, Ross;Wilcox, Laura J.;Frame, Dave
目前，南亚和东亚地区的人为气溶胶对亚洲夏季风（ASM）的影响比温室气体排放更大，但这些地区预计的气溶胶排放变化受到相当大的不确定性，如时间尺度，位置或排放类型。我们使用的环流/气候模式与理想的气溶胶分布，以证明ASM响应气溶胶减排在每个区域的总和是非常不同的响应同时减少在两个区域，这意味着ASM响应气溶胶减排是高度非线性的。这一现象与气溶胶是散射还是吸收无关，是大气环流变化相互作用的结果。来自不同地区的气溶胶强迫之间的相互作用的非线性代表了未来30-40年ASM变化预测的一个新的不确定性来源，并且在考虑其亚洲范围的影响时可能限制国家依赖的气溶胶轨迹的效用，尽管我们建议进一步工作以确定非线性是否被其他驱动因素缓冲。为了了解由于气溶胶减少而导致的ASM可能发生的变化，各国需要准确地考虑更广泛地区的减排量，而不是使用简单的情景和模拟器进行近似计算。因此，对强迫响应的非线性为受ASM影响的国家提出了一个区域公共产品问题，因为气溶胶减排的成本和收益没有内在化;事实上，来自印度和中国等不同国家的强迫共同决定了整个区域的结果。
Anthropogenic aerosols over South and East Asia currently have a stronger impact on the Asian summer monsoon (ASM) than greenhouse gas emissions, yet projected aerosol emission changes in these regions are subject to considerable uncertainties such as timescale, location, or emission type. We use a circulation/climate model with idealised aerosol distributions to demonstrate that the sum of ASM responses to aerosol emission reductions in each region is very different to the response to simultaneous reductions in both regions, implying the ASM response to aerosol emissions reductions is highly nonlinear. The phenomenon is independent of whether aerosols are scattering or absorbing, and results from interaction of induced atmospheric circulation changes. The nonlinearity from interactions between aerosol forcing from different regions represents a new source of uncertainty in projections of ASM changes over the next 30-40 years, and may limit the utility of country-dependent aerosol trajectories when considering their Asia-wide effects, though we recommend further work to establish whether the nonlinearity is buffered by other drivers. To understand likely changes in the ASM due to aerosol reductions, countries will need to accurately take account of emissions reductions from across the wider region, rather than approximating them using simple scenarios and emulators. The nonlinearity in the response to forcing therefore presents a regional public goods issue for countries affected by the ASM, as the costs and benefits of aerosol emissions reductions are not internalised; in fact, forcings from different countries such as India and China work jointly to determine outcomes across the region.