A Cumulus Parameterization with State-Dependent Entrainment Rate. Part I: Description and Sensitivity to Temperature and Humidity Profiles
A Cumulus Parameterization with State-Dependent Entrainment Rate. Part I: Description and Sensitivity to Temperature and Humidity Profiles
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具有状态相关夹带率的积云参数化。
DOI：
10.1175/2010jas3316.1
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发表时间：
2010
影响因子：
3.1
通讯作者：
M. Sugiyama
中科院分区：
文献类型：
--
作者：
M. Chikira;M. Sugiyama
摘要本文提出了一种新的积云参数化方案，其中采用了卷吸烟羽模式。横向卷吸率随周围环境而垂直变化。两种不同的配方进行检查的速度。根据云底上升气流速度谱表示积云系综。云底质量通量的确定与预报对流动能闭合。云底附近的卷吸率往往很大，这是因为云底附近的上升气流速度很小。当对流有效位能较小时，由于云内湿静力能的向上减少，深对流趋于被抑制。干燥的环境空气显着降低了云内湿度，主要是因为对流层低层的大夹带率，这导致了深对流的抑制，与观测和云解析模式的先前结果一致。卷吸率的变化有可能影响积云对流。
Abstract A new cumulus parameterization is developed for which an entraining plume model is adopted. The lateral entrainment rate varies vertically depending on the surrounding environment. Two different formulations are examined for the rate. The cumulus ensemble is spectrally represented according to the updraft velocity at cloud base. Cloud-base mass flux is determined with prognostic convective kinetic energy closure. The entrainment rate tends to be large near cloud base because of the small updraft velocity near that level. Deep convection tends to be suppressed when convective available potential energy is small because of upward reduction of in-cloud moist static energy. Dry environmental air significantly reduces in-cloud humidity mainly because of the large entrainment rate in the lower troposphere, which leads to suppression of deep convection, consistent with observations and previous results of cloud-resolving models. The change in entrainment rate has the potential to influence cumulus conve...