Common Variability in the Stable Atmospheric Boundary Layer on Small Space and Time Scales

小时空尺度上稳定大气边界层的常见变化

基本信息

批准号：
1945587
负责人：
Larry Mahrt
金额：
$ 55.07万
依托单位：
NorthWest Research Associates, Incorporated
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-01-15 至 2023-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945587&HistoricalAwards=false
关键词：
Common Variability Stable Atmospheric Boundary

项目摘要

A regular nighttime occurrence is the development of a stable boundary layer, which is a shallow, near-calm layer of air near the Earth’s surface. However, despite the air seemingly being calm, there are ongoing motions which have important impacts on near-ground temperatures and the dispersion of pollutants. This research award provides support for the analysis of existing observational data on stable boundary layer motions, with a fresh look at how they can be tracked and how that information can be used to improve numerical weather models. A specific use case that this award will address, in consultation with local field managers, is vineyards in the Pacific Northwest where frosts and freezes have a significant impact.The research under this award will expand understanding of small-scale, non-stationary motions, their interaction with surface heterogeneity, and their stochastic behavior. The focus is on submeso motions, which are formally defined to include motions on scales just larger than the largest turbulent eddies and up to scales normally considered to be the smallest mesoscale motions (2km). A sequence of case studies of different types of small-scale motions will be constructed using data from 9 prior field campaigns and a package of different analysis methods that has been developed by the researcher. The main objectives of the proposal are to: 1) Quantify the submeso time and space variability of the temperature, the wind vector, and turbulent fluxes and relate these variations to the forcing variables, 2) Track propagating modes across networks of data and examine their interaction with surface-based phenomena due to gentle topography and the impact of this interaction on turbulent fluxes, 3) Formulate probability distributions for short-term (non-turbulent) variations of the temperature and wind direction for low wind speeds and relate the characteristics of the distributions to the forcing variables, and 4) Reanalyze the behavior of the fluxes and corresponding transfer coefficients in the bulk formula for low wind speeds based on time averaging and based on spatial averaging across the networks and improve formulation of the transfer coefficients for low wind speeds.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

常规的夜间发生是稳定边界层的发展，稳定的边界层是地球表面附近的浅层，近高的空气层。但是，努力奋斗似乎是平静的，正在进行的动议对近地温度和污染物的分散产生重要影响。该研究奖为分析稳定边界层动作的现有观察数据提供了支持，并详细介绍了如何跟踪它们以及如何使用该信息来改善数值天气模型。该奖项将与当地野外经理协商的特定用例是太平洋西北地区的葡萄园，那里的葡萄园有重大影响。该奖项下的研究将扩大对小规模，非平稳运动的理解，它们与表面异质性的相互作用以及其随机行为。重点放在了子动作上，该动作被正式定义为包括比最大的湍流涡流大的尺度上的运动，最多可被认为是最小的中尺度运动（2km）的尺度。研究人员开发的一系列数据和一系列不同的分析方法，将对不同类型的小规模动作进行一系列案例研究。该提案的主要目标是：1）量化温度，风向矢量和湍流的集合时间和空间的变化，并将这些变化与强迫变量相关联，2）跟踪数据网络的轨迹跨数据网络的传播，并检查其与该相互作用的相互作用以及对不及格的影响的基于表面的相互作用，并分配了不及时的湍流，3），3），3），3）湍流的影响，3）湍流（3）的影响，3）低风速的温度和风向，并将分布的特征与强迫变量联系起来，以及4）重新分析了磁通量的行为，并基于时间平均和基于空间平均范围的空间平均和改进的统计范围的统计范围，并反映了统计范围的范围，并反映了低风速的低风速和相应的传输系数通过使用基金会的知识分子和更广泛影响的评论标准来通过评估来支持。