Impact of soil moisture and convectively generated waves on the initiation of a West African mesoscale convective system
Impact of soil moisture and convectively generated waves on the initiation of a West African mesoscale convective system
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土壤湿度和对流产生的波对西非中尺度对流系统启动的影响
DOI：
10.1002/qj.2062
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发表时间：
2012
影响因子：
8.9
通讯作者：
Birch C
中科院分区：
文献类型：
--
作者：
Birch C
2006年7月31日，作为非洲季风多学科分析（AMMA）的一部分，在马里东北部观测到一个中尺度对流系统（MCS）个例研究。这种情况下的观测表明，土壤水分的不均匀性和大气重力波发射的“母”MCS是这个系统的重要触发机制。这项研究使用高分辨率气象局统一模型（MetUM）模拟来评估天气环流，陆面和重力波在MCS的开始和发展中的重要性。下午早些时候，天气尺度辐合带内的一片干燥土壤上空发展出浅层对流，这是由偏南季风气流与撒哈拉热低压周围环流相关的风汇合而成。两个明显的波是从附近的“母”风暴发出的，并向辐合区传播。当第二波到达浅层对流的位置时，深层对流立即开始。下午晚些时候，干燥的土壤上进一步发展出对流单体，其中许多与强烈的土壤湿度梯度相邻;这些单体与主风暴聚集在一起，后来发展成个例研究MCS。有/无土壤水分异质性和重力波的模式模拟的比较表明，由大气分析指定的天气尺度环流和辐合区是成功模拟MCS的最重要因素。如果要准确地预测系统启动的位置，就必须充分代表地表，即土壤湿度。为了正确地再现二次对流开始的时间，模型必须能够捕获由现有系统发射的重力波。
A mesoscale convective system (MCS) case study was observed over northeast Mali as part of the African Monsoon Multidisciplinary Analysis (AMMA) on 31 July 2006. Observations of this case suggest that the soil‐moisture heterogeneity and atmospheric gravity waves emitted from a ‘parent’ MCS were important trigger mechanisms for this system. This study uses high‐resolution Met Office Unified Model (MetUM) simulations to assess the importance of the synoptic circulation, land‐surface and gravity waves in the initiation and development of the MCS. During the early afternoon shallow convection developed over a region of dry soil within a synoptic‐scale convergence zone, which was caused by the confluence of the southerly monsoon flow with winds associated with the circulation around the Saharan heat low. Two pronounced waves were emitted from a nearby ‘parent’ storm and propagated towards the convergence zone. When the second wave reached the location of the shallow convection, deep convection was immediately initiated. Further convective cells developed later in the afternoon over dry soil, many adjacent to strong soil moisture gradients; these aggregated with the main storm, which later developed into the case study MCS. A comparison of model simulations with/without the soil‐moisture heterogeneity and gravity waves shows that the synoptic‐scale circulation and convergence zones, specified by the atmospheric analysis, were the most important factors for the successful simulation of the MCS. If the location of the initiation of the system is to be forecast accurately, the land‐surface, that is, the soil moisture, must be represented adequately. In order to reproduce the timing of the secondary initiation of convection correctly the model must be able to capture gravity waves that are emitted by existing systems.
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影响因子：
8
作者：
F. Hourdin;I. Musat;F. Guichard;P. Ruti;F. Favot;M. Filiberti;M. Pham;J. Grandpeix;J. Polcher;P. Marquet;A. Boone;J. Lafore;J. Redelsperger;A. Dell’Aquila;T. L. Doval;A. Traore;H. Gallee
通讯作者：
F. Hourdin;I. Musat;F. Guichard;P. Ruti;F. Favot;M. Filiberti;M. Pham;J. Grandpeix;J. Polcher;P. Marquet;A. Boone;J. Lafore;J. Redelsperger;A. Dell’Aquila;T. L. Doval;A. Traore;H. Gallee
辐合区及其对西非中尺度对流系统启动的影响
DOI：
--
发表时间：
2012
期刊：
影响因子：
--
作者：
V. Klüpfel;N. Kalthoff;L. Gantner;C. Taylor
通讯作者：
C. Taylor
影响因子：
56.9
作者：
Koster, RD;Dirmeyer, PA;Yamada, T
通讯作者：
Yamada, T
评估西非对流允许模型模拟中的土壤湿度集合运行以估计降水变化
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
V. Klüpfel;N. Kalthoff;L. Gantner;C. Kottmeier
通讯作者：
C. Kottmeier
DOI：
--
发表时间：
1985
期刊：
影响因子：
--
作者：
N. A. Crook;M. Miller
通讯作者：
M. Miller