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首页> 外文期刊>Journal of the Atmospheric Sciences >Multicloud models for organized tropical convection: Enhanced congestus heating
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Multicloud models for organized tropical convection: Enhanced congestus heating

机译：用于有组织的热带对流的多云模型：增强的充血加热

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Despite the recent advances in supercomputing, the current general circulation models (GCMs) poorly represent the large-scale variability associated with tropical convection. Multicloud model convective parameterizations based on three cloud types (congestus, deep, and stratiform), introduced recently by the authors, have been revealed to be very useful in representing key features of organized convection and convectively coupled waves. Here a new systematic version of the multicloud models is developed with separate upper- and lower-troposphere basis functions for the congestus and stratiform clouds. It naturally leads to a new convective closure for the multicloud models enhancing the congestus heating in order to better pinpoint the congestus preconditioning and moistening mechanisms. The models are studied here for flows above the equator without rotation effects. First, the Dew model results consist of the usual synoptic-scale convectively coupled moist gravity wave packets moving at 15-20 m s(-1) but, in addition, these packets have planetary-scale envelopes moving in the opposite direction at about 6 m s(-1) and have many of the self-similar features of convectively coupled waves, reminiscent of the Madden-Julian oscillation. Second, when a warm pool forcing is imposed, dry regions of roughly 250 km in extent form "convective barriers" surrounding the warm pool region where only congestus heating survives. Deep convection and moist gravity waves are thus confined within the warm pool region. Finally, linear analysis reveals that, for sufficiently dry mean states, in addition to the inherent synoptic-scale moist gravity waves, the new model supports a planetary (wavenumber 1) standing congestus mode that provides, within its congestus active phase, a region where moist gravity waves evolve and propagate, which results in a Walker-like circulation over a uniform SST background.
机译：尽管最近在超级计算方面取得了进展，但当前的一般循环模型（GCM）仍不能很好地代表与热带对流有关的大规模变化。作者最近介绍了基于三种云类型（充血，深层和层状）的多云模型对流参数化，对表示有组织对流和对流耦合波的关键特征非常有用。在这里，开发了一个新的系统模型的多云模型，该模型具有分别用于阻塞和层状云的对流层和低层对流层的基础功能。它自然会导致针对多云模型的新对流闭合，从而增强拥塞加热，以便更好地确定拥塞的预处理和润湿机制。这里研究的模型是针对赤道上方的流动而没有旋转效应的。首先，露水模型的结果包括通常的对流尺度对流耦合湿重力波包，它们以15-20 ms（-1）的速度运动，但此外，这些数据包具有行星尺度的包络线，它们在大约6 ms的相反方向上运动（-1）并具有对流耦合波的许多自相似特征，让人联想到Madden-Julian振荡。其次，当施加温池强迫时，大约250公里范围内的干燥区域会在温池区域周围形成“对流壁垒”，其中仅存在充血。因此，深对流和湿重力波被限制在温暖的水池区域内。最后，线性分析表明，对于足够干燥的平均状态，除了固有的天气尺度的湿重力波，新模型还支持行星（波数1）站立的拥塞模式，该模式在其拥塞活动相中提供了一个区域潮湿的重力波会产生并传播，这会在统一的SST背景上形成类似Walker的循环。

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