The effect of coherent stirring on the advection-condensation of water vapour.
The effect of coherent stirring on the advection-condensation of water vapour.
复制标题
DOI：
10.1098/rspa.2017.0196
复制
发表时间：
2017-06
期刊：
影响因子：
--
通讯作者：
Vanneste J
中科院分区：
文献类型：
--
作者：
Tsang YK;Vanneste J
大气中的水蒸气是天气和气候的基本组成部分。其分布的关键特征可以由运动学模型表示，该模型将其视为由指定流平流输送并通过冷凝反应的被动标量。冷凝作用就像一个水槽，使比湿度保持在规定的、与空间有关的饱和值以下。为了研究大尺度平流，小尺度湍流和冷凝之间的相互作用如何控制水分分布，我们开发了简单的运动学模型，它联合收割机一个单一的循环流与湍流的布朗运动表示。我们首先研究了在初始时刻涡旋内部释放的水汽异常的干燥机制。接下来，我们考虑在边界处具有湿气源的细胞流。达到统计稳定状态显示功能让人想起的Hadley细胞，如边界层，一个区域的强降水和相对湿度最低。明确的结果提供了一个详细的描述这些功能的限制强流。
Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow.