The Effects of Explicit versus Parameterized Convection on the MJO in a Large-Domain High-Resolution Tropical Case Study. Part II: Processes Leading to Differences in MJO Development
The Effects of Explicit versus Parameterized Convection on the MJO in a Large-Domain High-Resolution Tropical Case Study. Part II: Processes Leading to Differences in MJO Development
复制标题
大域高分辨率热带案例研究中显式与参数化对流对 MJO 的影响。
DOI：
10.1175/jas-d-14-0308.1
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发表时间：
2015
影响因子：
3.1
通讯作者：
Holloway C
中科院分区：
文献类型：
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作者：
Holloway C
在一次为期10天的活跃Madden-Julian振荡（MJO）个例研究中，分析和比较了使用显式对流和参数化对流对热带大区域（~20°S-20°N，42°E-180°）的高分辨率模拟。本文的第二部分是对大气的水分收支和湿熵收支进行了分析。垂直次网格非绝热加热廓线和垂直速度廓线也进行了比较，这些都与湿熵收支的水平和垂直平流分量有关，这有助于总湿稳定度（GMS）和归一化GMS（NGMS）。具有显式对流和良好MJO性能的4 km模式具有随高度增加的垂直加热结构，在对流层下部的强对流区域（如观测），而具有参数化对流和较差MJO的12 km模式没有显示出这种关系。4公里的显式对流模式也有一个更头重脚轻的加热剖面对流层作为一个整体附近和以西的活跃MJO相关的对流，不像12公里的参数化对流模式。在所有模型中，熵平流分量对湿度收敛的依赖性都相当弱，模型之间的差异并不总是与MJO性能相关，与以前的工作进行比较有些不确定。然而，MJO强度和传播相对较好的模式，随着水汽辐合的增加，垂直平流分量的增加幅度略大，其NGMS垂直项在时间和经度上的变化性更大，总NGMS相对较大西部和东部较小。
High-resolution simulations over a large tropical domain (~20°S–20°N, 42°E–180°) using both explicit and parameterized convection are analyzed and compared during a 10-day case study of an active Madden–Julian oscillation (MJO) event. In this paper, Part II of this study, the moisture budgets and moist entropy budgets are analyzed. Vertical subgrid diabatic heating profiles and vertical velocity profiles are also compared; these are related to the horizontal and vertical advective components of the moist entropy budget, which contribute to gross moist stability (GMS) and normalized GMS (NGMS). The 4-km model with explicit convection and good MJO performance has a vertical heating structure that increases with height in the lower troposphere in regions of strong convection (like observations), whereas the 12-km model with parameterized convection and a poor MJO does not show this relationship. The 4-km explicit convection model also has a more top-heavy heating profile for the troposphere as a whole near and to the west of the active MJO-related convection, unlike the 12-km parameterized convection model. The dependence of entropy advection components on moisture convergence is fairly weak in all models, and differences between models are not always related to MJO performance, making comparisons to previous work somewhat inconclusive. However, models with relatively good MJO strength and propagation have a slightly larger increase of the vertical advective component with increasing moisture convergence, and their NGMS vertical terms have more variability in time and longitude, with total NGMS that is comparatively larger to the west and smaller to the east.