Impacts of recent decadal changes in Asian aerosols on the East Asian summer monsoon: roles of aerosol-radiation and aerosol-cloud interactions
Impacts of recent decadal changes in Asian aerosols on the East Asian summer monsoon: roles of aerosol-radiation and aerosol-cloud interactions
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DOI：
10.1007/s00382-019-04698-0
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发表时间：
2019-09-01
期刊：
影响因子：
4.6
通讯作者：
Sutton, Rowan T.
中科院分区：
文献类型：
--
作者：
Dong, Buwen;Wilcox, Laura J.;Sutton, Rowan T.
人为气溶胶（AA）可以通过气溶胶-辐射相互作用（ARI）和气溶胶-云相互作用（ACI）影响云和降水。在过去的几十年里，人为气溶胶排放的规模和空间格局发生了显着的变化。最显著的变化是南亚和东亚的排放量增加。在这项研究中，一个国家的最先进的气候模式，其中包括8种对流层气溶胶的大气成分，耦合到一个多层混合层海洋模式，已被用来研究亚洲人为气溶胶前体物排放的变化，从20世纪70年代到21世纪00年代的大尺度环流和降水在东亚北部夏季的影响。结果表明，东亚和热带及西北太平洋（WNP）上空的环流和云的显着变化。亚洲AA排放的增加导致海洋大陆（MC）异常气旋性环流和WNP异常反气旋性环流，导致MC异常水汽输送辐合，从而增加降水。它们还导致了西北太平洋和东亚大面积陆地，特别是中国北方地区的异常水汽通量辐散，从而导致降水减少。这些大尺度的环流异常在邻近的海洋气溶胶变化引起的海洋反馈，主要是通过ACI。它是邻近海洋上的缓慢反应（例如，在季风前和夏季，通过耦合的大气-海洋相互作用，形成东亚夏季风和当地降水的变化。研究结果表明，亚洲大气AA排放的增加可能对世纪后半叶太平洋热带辐合带和降水带的南移、东亚夏季风的减弱以及中国北方降水的减少起了重要作用。
Anthropogenic aerosols (AA) can affect cloud and precipitation through aerosol-radiation interaction (ARI) and aerosol-cloud interaction (ACI). Over the past few decades, anthropogenic aerosol emissions have exhibited remarkable changes in the magnitude and in spatial pattern. The most significant changes are the increased emissions over both South Asia and East Asia. In this study, the atmospheric component of a state-of-the-art climate model that includes eight species of tropospheric aerosols, coupled to a multi-level mixed-layer ocean model, has been used to investigate the impacts of Asian anthropogenic aerosol precursor emission changes from 1970s to 2000s on large scale circulation and precipitation in boreal summer over East Asia. Results reveal significant changes in circulation and clouds over East Asia and over the tropical and western North Pacific (WNP). Increased Asian AA emissions lead to anomalous cyclonic circulation over the Maritime continent (MC) and anomalous anticyclonic circulation over the WNP, resulting in anomalous moisture transport convergence over the MC and therefore increased precipitation. They also lead to anomalous moisture flux divergence over both the WNP and large land areas of East Asia, especially over northern China, and therefore decreased precipitation there. These large scale circulation anomalies over the adjacent oceans are related to aerosol change induced ocean feedbacks, predominantly through ACI. It is the slow responses over the adjacent oceans (e.g., SST changes) through coupled atmosphere-ocean interaction in pre-monsoon seasons and summer that shape the changes of the East Asian summer monsoon and local precipitation. The results in this study suggest that increased Asian AA emissions from 1970s to 2000s may have played an important role for the observed southward shift of the Pacific intertropical convergence zone and precipitation belt, weakening of East Asian summer monsoon and reduced precipitation over northern China in East Asia during the latter half of the twentieth century.