The Effect of Moist Processes on Midlatitude Static Stability

潮湿过程对中纬度静稳定性的影响

• 批准号: 0936059
• 负责人: Dargan Frierson
• 金额: $ 32.94万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-15 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0936059&HistoricalAwards=false
• 关键词: Effect; Moist; Processes; Midlatitude; Static

Research conducted under this grant will study the static stability of that portion of the atmosphere (specifically the troposphere and lower stratosphere) which lies between the warm tropics and the cold polar caps (i.e. the midlatitudes). The static stability of the atmosphere is a key factor which influences many aspects of atmospheric behavior, including the frequency and intensity of convective precipitation, the propagation speed of various kinds of atmospheric wave motions, the horizontal size required for atmospheric circulation patterns to be strongly influenced by the Coriolis force, and even the strength of the atmospheric greenhouse effect. Stability is determined by the vertical variation of temperature with height, and processes which warm the upper atmosphere relative to the lower atmosphere (i.e. lessen the rate at which temperature decreases with height in the troposphere) cause an increase in static stability. The particular focus of this project is the extent to which the condensation of atmospheric water vapor and the attendant warming of the upper atmosphere by latent heating is important for determining the stability of the midlatitude atmosphere. Many previous studies have suggested that the stability of the midlatitude atmosphere is primarily determined by baroclinic instability, which can be thought of roughtly as the action of frontal systems in which warm air masses from the south are displaced by cold air masses from the north. However, some studies have shown that condensational heating could have a potentially large impact on the static stability, and it is generally accepted that condensational heating associated with convection is a primary determinant of static stability in the tropics. Research conducted under this grant will use a hierarchy of atmospheric models of varying degrees of complexity, in combination with the most recent and accurate observational datasets, to understand the fundamental physical and dynamical processes through which moisture influences midlatitude stability.The determination of midlatitude static stability is a classical problem in fundamental atmospheric science, but it also has practical real-world consequences. Previous work by the principal investigator and others shows that midlatitude stability increases with global warming, with potentially significant consequences for the hydrological cycle. In addition to the scientific broader impacts, the work would contribute to education by funding two graduate students. Scientists conducting the work will also present their research results to the public in a short video, prepared using the resources of their university.

在这项资助下进行的研究将研究位于温暖的热带和寒冷的极地帽（即中纬度地区）之间的那部分大气（特别是对流层和平流层下层）的静态稳定性。大气的静态稳定性是影响大气行为许多方面的关键因素，包括对流降水的频率和强度、各种大气波动的传播速度、大气环流型受科里奥利力强烈影响所需的水平大小，甚至大气温室效应的强度。稳定性是由温度随高度的垂直变化决定的，使高层大气相对于低层大气变暖的过程（即降低对流层温度随高度下降的速率）导致静态稳定性的增加。这个项目的特别重点是大气水蒸气的凝结和伴随而来的上层大气潜热变暖在多大程度上对确定中纬度大气的稳定性是重要的。许多先前的研究表明，中纬度大气的稳定性主要是由斜压不稳定性决定的，这可以大致认为是锋面系统的作用，其中来自南方的暖气团被来自北方的冷空气团取代。然而，一些研究表明，冷凝加热可能对静态稳定性产生潜在的巨大影响，人们普遍认为，与对流相关的冷凝加热是热带静态稳定性的主要决定因素。在这项资助下进行的研究将使用不同复杂程度的大气模型等级，结合最新和最精确的观测数据集，以了解水分影响中纬度稳定性的基本物理和动力过程。确定中纬度静态稳定性是基础大气科学中的一个经典问题，但它也具有实际的现实后果。首席研究员和其他人之前的工作表明，中纬度稳定性随着全球变暖而增加，这可能对水文循环产生重大影响。除了更广泛的科学影响外，这项工作还将通过资助两名研究生来为教育做出贡献。从事这项工作的科学家还将利用他们所在大学的资源，制作一段短视频，向公众展示他们的研究成果。