Aerosol microphysical and radiative effects on continental cloud ensembles
Aerosol microphysical and radiative effects on continental cloud ensembles
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DOI：
10.1007/s00376-017-7091-5
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发表时间：
2018-01
影响因子：
5.8
通讯作者：
Y. Wang;John M. Vogel;Yun Lin;B. Pan;Jiaxi Hu;Yangang Liu;Xiquan Dong;J. Jiang;Y. Yung;Renyi Zhang
中科院分区：
文献类型：
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作者：
Y. Wang;John M. Vogel;Yun Lin;B. Pan;Jiaxi Hu;Yangang Liu;Xiquan Dong;J. Jiang;Y. Yung;Renyi Zhang
气溶胶-云-辐射相互作用是当前气候评估中最大的不确定性之一。大部分复杂性源于不同气象条件下云、降水和辐射通量对气溶胶扰动的非单调响应。在本研究中，使用气溶胶感知 WRF 模型来研究 2000 年 3 月美国南部大平原云密集观测期活动期间三个天气系统中气溶胶的微物理和辐射影响。三个模拟云团包括低压深对流云系统、降水较少的层云和浅积云的集合以及冷锋通道。 WRF 模拟通过多项地面测量进行评估。云水凝结物的微物理特性，例如它们的质量和数量浓度，通常显示出作为云凝结核浓度的函数的单调趋势。气溶胶辐射效应不影响云微物理的趋势，除了层云和浅积云情况，其中确定了气溶胶半直接效应。气溶胶对降水的变化随云类型及其演化阶段的不同而变化，气溶胶增强效应显着，对流源降水增强。模拟的气溶胶直接效应抑制了所有三种情况的降水，但没有推翻气溶胶间接效应。云分数对气溶胶扰动的敏感性要小得多（通常小于 2%），并且响应随气溶胶浓度和云状态而变化。地表短波辐射随着气溶胶的增加而呈现单调减少的趋势，而减少的幅度取决于云的类型。
Aerosol–cloud–radiation interactions represent one of the largest uncertainties in the current climate assessment. Much of the complexity arises from the non-monotonic responses of clouds, precipitation and radiative fluxes to aerosol perturbations under various meteorological conditions. In this study, an aerosol-aware WRF model is used to investigate the microphysical and radiative effects of aerosols in three weather systems during the March 2000 Cloud Intensive Observational Period campaign at the US Southern Great Plains. Three simulated cloud ensembles include a low-pressure deep convective cloud system, a collection of less-precipitating stratus and shallow cumulus, and a cold frontal passage. The WRF simulations are evaluated by several ground-based measurements. The microphysical properties of cloud hydrometeors, such as their mass and number concentrations, generally show monotonic trends as a function of cloud condensation nuclei concentrations. Aerosol radiative effects do not influence the trends of cloud microphysics, except for the stratus and shallow cumulus cases where aerosol semi-direct effects are identified. The precipitation changes by aerosols vary with the cloud types and their evolving stages, with a prominent aerosol invigoration effect and associated enhanced precipitation from the convective sources. The simulated aerosol direct effect suppresses precipitation in all three cases but does not overturn the aerosol indirect effect. Cloud fraction exhibits much smaller sensitivity (typically less than 2%) to aerosol perturbations, and the responses vary with aerosol concentrations and cloud regimes. The surface shortwave radiation shows a monotonic decrease by increasing aerosols, while the magnitude of the decrease depends on the cloud type.