Doctoral Dissertation Research: Mesoscale Impacts of Soil Moisture on Convective Precipitation

该项目的目标是量化土壤湿度对对流降水的位置和发生的影响。虽然以前的许多研究试图描述和/或量化土壤水分对对流降水的影响，但还没有利用观测到的土壤水分测量或将土壤水分-降水相互作用分离为两个不同的组成部分(土壤水分-蒸发和蒸发-降水)。这些考虑对于研究土壤湿度直接影响对流降水的情况是必要的。该项目的三个主要目标是：(1)确定对流降水是优先于干土壤还是湿土壤，(2)量化土壤水分对低层大气温度和湿度的影响，以及(3)评估土壤水分空间梯度如何影响对流降水的可能性。地面雷达降水将用于识别中尺度对流系统。将为每个事件确定降水前的土壤湿度条件以及大气湿度和温度。还将为每个对流事件确定大气湿度的来源，以量化本地和远程来源的湿度的比例。这项研究的结果将加深我们对世界各地半干旱地区陆气相互作用的理解。土壤水分可能会对未来的降水产生影响。陆地表面和大气之间的这种耦合很重要，因为它为改进季节性气候预报提供了基础。该项目将使用俄克拉荷马州的土壤湿度观测来调查土壤湿度和降雨量之间的物理联系；这是一个重大的进步，因为以前的大多数研究都依赖于对土壤湿度的建模或基于卫星的估计。该项目将只侧重于局部对流降水事件，因为假设它们比大规模降水事件(例如，与暖锋和冷锋有关的降水事件)受土壤湿度的影响更大。土壤湿度不仅与随后的降雨量有关，还将研究土壤湿度与近地表大气之间的物理联系。这一项目的成果将加深我们对土壤水分如何影响对流降水以及在什么条件下地表对降水影响最大的理解。该项目的研究结果将通过会议报告和出版物向气候模型界传播。它将有助于提高季节性气候预测的准确性，因为现有的气候模型不能准确地代表陆地-大气相互作用。将从不同的本科生群体中聘请一名本科生研究人员助理，以协助收集、处理和分析数据。本科生将接受科学编程和数据可视化方面的专门培训，研究将在本科论文中总结，并将在全国科学会议上发表。

The goal of this project is to quantify the impact of soil moisture on the location and occurrence of convective precipitation. Although many previous studies have attempted to describe and/or quantify the impact of soil moisture on convective precipitation, none have used observed soil moisture measurements or separated soil moisture-precipitation interactions into the two distinct components (soil moisture-evaporation and evaporation-precipitation). These considerations are necessary to examine the cases in which soil moisture directly influences convective precipitation. The project's three main objectives are: (1) determine if convective precipitation falls preferentially over dry or wet soils, (2) quantify the influence that soil moisture has on low-level atmospheric temperature and humidity, and (3) evaluate how soil moisture spatial gradients influence the probability of convective precipitation. Ground-based radar precipitation will be used to identify mesoscale convective systems. The soil moisture conditions prior to precipitation and the atmospheric humidity and temperature will be determined for each event. The sources of atmospheric moisture will also be determined for each convective event to quantify the proportion of locally- and remotely-sourced moisture. The results of this research will enhance our understanding of land-atmosphere interactions in semi-arid regions around the world.Soil moisture can have an influence on future precipitation. This coupling between the land surface and the atmosphere is important because it provides the basis for improving seasonal climate forecasts. This project will use soil moisture observations in Oklahoma to investigate the physical linkages between soil moisture and precipitation; it is a significant advance since most prior studies have relied on modeled or satellite-based estimates of soil moisture. This project will focus only on localized convective precipitation events since they are hypothesized to be more strongly influenced by soil moisture than large-scale precipitation events (e.g., precipitation events associated with warm fronts and cold fronts). Soil moisture will not simply be correlated with subsequent precipitation, but the physical linkages between soil moisture and the near-surface atmosphere will be examined. The results of this project will enhance our understanding of how soil moisture influences convective precipitation and under what conditions the land surface has the strongest impact on precipitation. The findings of this project will be disseminated to the climate modeling community through conference presentations and publications. It will help improve the accuracy of seasonal climate forecasts since existing climate models do not accurately represent land-atmosphere interactions. An undergraduate researcher assistant will be hired from a diverse group of undergraduate to assist with data collection, processing and analysis. The undergraduate student will receive specialized training in scientific programming and data visualization, and the research will be summarized in an undergraduate thesis and it will be presented at a national scientific meeting.