Nonlinear Response of Asian Summer Monsoon Precipitation to Emission Reductions in India and China
Nonlinear Response of Asian Summer Monsoon Precipitation to Emission Reductions in India and China
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亚洲夏季风降水对印度和中国减排的非线性响应
DOI：
10.1002/essoar.10507903.1
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Herbert R
中科院分区：
文献类型：
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作者：
Herbert R
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在时间尺度、位置、排放类型甚至变化的迹象方面都存在相当大的不确定性，这意味着未来ASM变化的不确定性很大。https://doi.org/10.1088/1748-9326/ac3b19此外，南亚或东亚的气溶胶变化造成环流异常，影响到各国和邻近区域。我们使用一个环流/气候模式来证明，ASM响应的总和在每个区域的单个气溶胶减排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。这种现象与气溶胶是散射还是吸收无关，而是由两个区域之间的大尺度遥相关驱动的。非线性是未来30-40年ASM变化预测中的一个新的不确定性来源，并限制了考虑其亚洲范围影响时依赖于国家的气溶胶轨迹的实用性。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，对强迫反应的非线性对于受ASM影响的国家来说是一个区域公共产品问题，因为减少气溶胶排放的成本和收益并未内在化;事实上，来自不同国家的强迫共同决定整个地区的结果。
Now published: https://doi.org/10.1088/1748-9326/ac3b19 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 uncertainty in timescale, location, emission type, and even the sign of the change, implying large uncertainties in future ASM change. In addition, aerosol changes in either South or East Asia cause circulation anomalies that affect both countries and neighbouring regions. We use a circulation/climate model to demonstrate that the sum of ASM responses to individual 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 is driven by large-scale teleconnections between the two regions. The nonlinearity represents a new source of uncertainty in projections of ASM changes over the next 30-40 years, and limits the utility of country-dependent aerosol trajectories when considering their Asia-wide effects. 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 work jointly to determine outcomes across the region.