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

North Carolina State University, Raleigh NC

Investigators

Abstract

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.