Studies in the Climate Dynamics of Moist Processes

本项目研究热带对流降雨的基本特征及其与大尺度大气条件的复杂关系。这项工作建立在同一小组之前的工作基础上，他们发现，热带降水的几个重要属性，包括出现频率、方差和强度，在处理为总体大气水汽含量除以与温度相关的饱和比湿度相关的临界水汽值时，表现出简单的行为。这项工作分为四个主题：1)对水汽、对流及其相互作用的观测约束；2)与输送过程有关的分布尾巴及其影响，特别是对极端降水事件的影响；3)降水模拟、潮湿遥相关和对流边缘问题；4)参数敏感性估计/优化方法，重点关注区域气候问题中的降水过程。热带对流降水的行为具有巨大的实际意义，因为热带地区的大部分人口是居住在热带的世界人口的水汽来源。然而，尽管热带对流很重要，但它的性质仍然神秘，因为对流降雨是由大尺度大气条件和小规模对流云特性之间的复杂相互作用决定的。这里开展的研究旨在提高对热带对流及其在天气和气候模式中的表现的理解，这种改进对面临热带气候可变性(包括厄尔尼诺事件)和热带气候变化的影响的决策者具有极大的潜在益处。

This project examines fundamental properties of tropical convective rainfall and its complex relationship to large-scale atmospheric conditions. The work builds on previous work by the same group which found that several important properties of tropical precipitation including frequency of occurrence, variance, and intensity, show simple behavior when treated as functions of bulk atmospheric water vapor content divided by a critical water vapor value related to temperature-dependent saturation specific humidity. The work is divided into four topics: 1) Observational constraints on representations of moisture, convection, and their interactions; 2) distribution tails associated with transport processes and their implications, particularly for extreme precipitation events; 3) Issues in precipitation simulation, moist teleconnections and convective margins, and 4) Methods for parameter sensitivity estimation/optimization with a focus on precipitation processes in regional climate issues.The behavior of convective precipitation in the tropics is of immense practical importance, as the source of moisture for the large portion of the world's population residing in the tropics. Yet despite its importance the nature of tropical convection remains mysterious, as convective rainfall is governed by complex interactions between large-scale atmospheric conditions and the properties of small-scale convective clouds. Research conducted here seeks to improve understanding of tropical convection and its representation in weather and climate models, and such improvements have great potential benefit for decision makers confronted with the impacts of tropical climate variability (including El Nino events) and tropical climate change.