Atmospheric Chemistry and Physics Global Anthropogenic Aerosol Effects on Convective Clouds in Echam5-ham
Atmospheric Chemistry and Physics Global Anthropogenic Aerosol Effects on Convective Clouds in Echam5-ham
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大气化学和物理 全球人为气溶胶对 Echam5-ham 对流云的影响
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
U. Lohmann
中科院分区：
文献类型：
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作者：
U. Lohmann
气溶胶通过在许多方面改变云的特征来影响气候系统。它们起着云凝结和冰核的作用，并可能对水文循环产生影响。本文将层状云的双矩云微物理方案与HAM双矩气溶胶方案相耦合，推广到ECHAM5大气环流模式中的对流云，研究了气溶胶对对流云的影响。这使我们能够研究更多和更小的云滴是否会抑制对流云下部的暖雨形成，从而在结冰时释放更多的潜热，从而导致更强烈的对流和更多的降水。在ECHAM5中，包括大尺度和对流云中的气溶胶效应(模拟ECHAM5-COV)降低了液态水路径的敏感性，随着气溶胶光学厚度的增加而增加，这与观测和大涡模拟研究更一致。在模拟ECHAM5-Conv中，与忽略对流云中的微物理相比，自前工业时代以来温室气体和气溶胶排放的增加，降水变化的地理分布与观测到的降水增加更匹配。在这次模拟中，对流降水增加最多，表明对流确实变得更加活跃。
Aerosols affect the climate system by changing cloud characteristics in many ways. They act as cloud condensation and ice nuclei and may have an influence on the hydrological cycle. Here we investigate aerosol effects on con-vective clouds by extending the double-moment cloud mi-crophysics scheme developed for stratiform clouds, which is coupled to the HAM double-moment aerosol scheme, to con-vective clouds in the ECHAM5 general circulation model. This enables us to investigate whether more, and smaller cloud droplets suppress the warm rain formation in the lower parts of convective clouds and thus release more latent heat upon freezing, which would then result in more vigorous convection and more precipitation. In ECHAM5, including aerosol effects in large-scale and convective clouds (simulation ECHAM5-conv) reduces the sensitivity of the liquid water path increase with increasing aerosol optical depth in better agreement with observations and large-eddy simulation studies. In simulation ECHAM5-conv with increases in greenhouse gas and aerosol emissions since pre-industrial times, the geographical distribution of the changes in precipitation better matches the observed increase in precipitation than neglecting microphysics in convective clouds. In this simulation the convective precipitation increases the most suggesting that the convection has indeed become more vigorous .