A Rational Approach to Cumulus Parameterization in Large-Scale Models

该项目采取了一种独特的方法来开发一种新的方法，用于在大尺度天气和气候模式中表示积云对流（即，任何空间分辨率低到不能直接解析云过程的模型）。 该项目将深入了解对流如何与环境相互作用-对流加热产生的浮力异常通过波浪作用迅速消除，这一过程产生平均垂直速度，产生足以抵消加热的绝热冷却。 作为其主要影响之一，这种“弱温度梯度垂直速度”平流水分。这一认识促使开发一个“测试单元”，其中显式积云集合模型和对流参数处理将进行测试。 研究人员将使用这些结果来修改和调整现有的原型积云参数化。 然后将在一个大尺度模式中使用这一参数化，以评估其对模拟的大气环流特征，如热带东风波和季节内振荡的影响。 昼夜周期也将在一个简化的背景下进行检查。 该项目将支持本科生和研究生的研究。

This project takes a unique approach to develop a new method for representing cumulus convection in large-scale weather and climate models (i.e., any models with spatial resolution low enough that they do not resolve cloud processes directly). The project will exploit insights into how convection interacts with its environment -- buoyancy anomalies produced by convective heating are quickly removed by wave action, a process which produces a mean vertical velocity that creates adiabatic cooling just sufficient to counterbalance the heating. As one of its main effects, this "weak temperature gradient vertical velocity" advects moisture. This realization motivates the development of a "test cell" in which explicit cumulus ensemble models and parametric treatments of convection will be tested. The investigators will use these results to modify and tune an existing prototype cumulus parameterization. This parameterization would then be used in a large-scale model to evaluate its effects on simulated features of the general circulation of the atmosphere such as tropical easterly waves and intraseasonal oscillations. The diurnal cycle will also be examined in a simplified context. The project will support research by undergraduate students as well as graduate students.