A Process Study on Thinning of Arctic Winter Cirrus Clouds With High‐Resolution ICON‐ART Simulations
A Process Study on Thinning of Arctic Winter Cirrus Clouds With High‐Resolution ICON‐ART Simulations
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DOI：
10.1029/2018jd029815
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发表时间：
2019-06
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影响因子：
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通讯作者：
S. Gruber;U. Blahak;F. Haenel;C. Kottmeier;T. Leisner;H. Muskatel;T. Storelvmo;B. Vogel
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文献类型：
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作者：
S. Gruber;U. Blahak;F. Haenel;C. Kottmeier;T. Leisner;H. Muskatel;T. Storelvmo;B. Vogel
在这项研究中，对冬季北极有限区域的案例研究进行了云解析模拟，并使用了大气模拟系统ICON‐ART（ICOsahedral Nonhydrostatic‐Aerosol and Reactive Trace gases）。一个彻底的比较，从卫星以及飞机测量的数据，以验证模拟。此外，该模式被应用于澄清微物理过程时，引入人工气溶胶粒子到对流层上层的目的是修改卷云的气候工程的框架。以前的模拟研究调查这种方法的气候影响进行了简化的假设和更粗糙的分辨率，达到部分矛盾的结论，该方法的有效性。播种的主要效果是减少卷云中的冰晶数浓度，导致大气层顶部的向外长波辐射通量增加，从而产生冷却效应。此外，二次效应被发现，作为冰晶形成的注入播种气溶胶粒子导致增强的云滴在行星边界层内的边缘。这有效地减少了混合相云的覆盖范围，从而通过增加地表向上的长波辐射通量来产生额外的冷却。卷云的播种效果相对独立于大气背景条件，与播种粒子的数量浓度成比例，并且对于大的气溶胶粒子是最高的。
In this study, cloud‐resolving simulations of a case study for a limited area of the hibernal Arctic were performed with the atmospheric modeling system ICON‐ART (ICOsahedral Nonhydrostatic‐Aerosol and Reactive Trace gases). A thorough comparison with data both from satellite as well as aircraft measurement is presented to validate the simulations. In addition, the model is applied to clarify the microphysical processes occurring when introducing artificial aerosol particles into the upper troposphere with the aim of modifying cirrus clouds in the framework of climate engineering. Former modeling studies investigating the climate effect of this method were performed with simplifying assumptions and much coarser resolution, reaching partly contradicting conclusions concerning the method's effectiveness. The primary effect of seeding is found to be a reduction of ice crystal number concentrations in cirrus clouds, leading to increased outgoing longwave radiative fluxes at the top of the atmosphere, thereby creating a cooling effect. Furthermore, a secondary effect is found, as ice crystals formed from the injected seeding aerosol particles lead to enhanced riming of cloud droplets within the planetary boundary layer. This effectively reduces the coverage of mixed‐phase clouds, thus generating additional cooling by increased upward longwave radiative fluxes at the surface. The efficacy of seeding cirrus clouds proves to be relatively independent from the atmospheric background conditions, scales with the number concentrations of seeding particles, and is highest for large aerosol particles.