Sensitivity of moist convection to environmental humidity
Sensitivity of moist convection to environmental humidity
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DOI：
10.1256/qj.03.130
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发表时间：
2004-10-01
影响因子：
8.9
通讯作者：
Soares, PMM
中科院分区：
文献类型：
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作者：
Derbyshire, SH;Beau, I;Soares, PMM
作为 EUROCS（欧洲云系统研究）项目的一部分，提出了潮湿大气对流对对流层中层湿度敏感性的云解析模型（CRM）模拟和并行单柱模型（SCM）测试。这种敏感性得到了观察和一些先前模型研究的广泛支持，但仍然缺乏量化。云和环境之间的混合是一个关键机制，是对流方案之间许多基本差异的核心。在这里，我们定义了一个理想化的准稳态“测试台”，其中假设大规模环境在一小时的时间尺度上调整局部平均剖面。然后，我们测试了对 2 公里以上高度的目标剖面的灵敏度。两个独立的 CRM 对不同背景剖面的响应相当一致，并且在较潮湿的情况下都显示出强烈的深层降水对流，但在最干燥的情况下仅显示浅对流。 CRM 结果在数字上似乎也很稳健。所有 SCM（其中大部分是全球气候模型 (GCM) 的一维版本）都显示出对湿度的敏感性，但与 CRM 在许多方面有所不同。根据这些比较，一些 SCM 得到了改进，GCM 的改进已在其他地方记录。
As part of the EUROCS (EUROpean Cloud Systems study) project, cloud-resolving model (CRM) simulations and parallel single-column model (SCM) tests of the sensitivity of moist atmospheric convection to midtropospheric humidity are presented. This sensitivity is broadly Supported by observations and some previous model studies, but is still poorly quantified. Mixing between clouds and environment is a key mechanism, central to many of the fundamental differences between convection schemes.Here, we define an idealized quasi-steady 'testbed', in which the large-scale environment is assumed to adjust the local mean profiles on a timescale of one hour. We then test sensitivity to the target profiles at heights above 2 km.Two independent CRMs agree reasonably well in their response to the different background profiles and both show strong deep precipitating convection in the more moist cases, but only shallow convection in the driest case. The CRM results also appear to be numerically robust. All the SCMs, most of which are one-dimensional versions of global climate models (GCMs), show sensitivity to humidity but differ in various ways from the CRMs. Some of the SCMs are improved in the light of these comparisons, with GCM improvements documented elsewhere.