The Role of Land Atmosphere Interactions on Quantitative Precipitation Forecasts and Convective Initiation over the Southern Great Plains

提高对美国南部大平原（SGP）暖季降水过程的理解是美国天气研究计划的一个研究重点。 利用国际H2O项目（IHOP）的观测结果，主要研究人员将研究多尺度陆面/大气相互作用及其对SGP深对流的启动和加强的影响，并改善暖季降雨的诊断和预测。研究人员将使用气孔阻力/生物物理测量来表征气孔阻力的时空变化，蒸腾作用，从而在SGP的典型景观的水汽交换。 研究活动的主要内容包括：（1）修改陆面模式（LSM）物理学，涉及土壤水分/土壤温度同化、基于光合作用的陆面模式增强、考虑散射辐射和显式地形效应，以了解土壤水分和植被代表对对流和对流降水的影响;（2）用情景对流风暴分析和用高分辨率耦合中尺度数值模式进行一个月的模拟来检验LSM;以及（3）诊断土壤之间的耦合/相互作用路径的性质，植被和大气对流导致对流位和对流降水使用集合和统计-动态因素分离分析 这项研究将解决调查陆面、行星边界层和云辐射过程之间复杂的相互作用及其对深对流发展的影响的需要，并改进模式定量降水预报技能。 作为一个更广泛的影响，这项研究涉及参与一个合作项目，并在研究活动中整合本科生和研究生的研究论文。 研究的成功完成可能会对对流开始的预测产生积极的影响。

Improving the understanding of warm-season precipitation processes in the U.S. Southern Great Plains (SGP) is a research priority of the U.S. Weather Research Program. Using observations from the International H2O Project (IHOP), the Principal Investigators will study the multi-scale land-surface/atmosphere interactions and their impacts on the initiation and intensification of deep convection in the SGP and improve the diagnosis and prediction of warm season rain. The investigators will use stomatal resistance / biophysical measurements to characterize the temporal and spatial variations of stomatal resistance, transpiration and hence water vapor exchange over typical landscapes in the SGP. A broad outline of the research activities includes: (1) modifications to land surface model (LSM) physics relating to soil moisture / soil temperature assimilation, photosynthesis-based land surface model enhancements, and consideration of diffuse radiation and explicit terrain effects, in order to understand the effects of soil moisture and vegetation representation on convection and convective precipitation; (2) testing of the LSM using episodic convective storm analyses, as well as month long simulations using a high resolution coupled mesoscale numerical model ; and (3) diagnosing the nature of the coupled / interactive pathways between the soil, vegetation and atmospheric convection leading to the convective potential and the convective precipitation using ensemble and statistical-dynamical factor separation analyses. The study will address the need to investigate the complex interactions between land surface, planetary boundary layer, and cloud-radiation processes, and their effects on the development of deep convection and improve model quantitative precipitation forecast skills. As a broader impact, the study involves participation in a collaborative program and integrating undergraduate and graduate student research theses within the research activities. Successful completion of the research may have a positive impact on the forecasting of convective initiation.