Evaluation of WRF using In-situ Measurements from IHOP 2002

A large array of state-of-the-art ground-based and airborne remote and in-situ sensors were deployed during the International H2O Project (IHOP), a field experiment that took place over the Southern Great Plains (SGP) of the United States from 13 May to 30 June 2002. These instruments provided extensive measurements of water vapor mixing ratio in order to better understand the influence of its variability on convection and on the skill of quantitative precipitation prediction (Weckwerth et al, 2004). A number of instruments have also observed detailed evolution and variability of the boundary layer height. Recent results of IHOP_2002 data analysis and model simulations will be presented.

This presentation will focus on the evolution and variability of moisture and wind in the boundary layer when frontal and/or convergence boundaries (e.g. bores, dry lines, thunderstorm outflows etc) were observed. The goals are to characterize the processes of convective initiation in association with drylines under different weather regimes, and to advance our understanding of the evolution of boundary layer during drylines that determine convective initiation. In particular, we focus on the sensitivities of convection and dryline structure with respect to the water vapor moisture. Two numerical studies during the IHOP_2002 are being conducted using the WRF model. The grid resolutions for both cases are 4 km with 1 km nested domains. The initial and boundary conditions are derived from the ETA model data. Additionally, the high resolution model simulation data provides an opportunity to compare model output and Lidar-based products as well as the in situ measurements in the IHOP domain. Results from this study will be compared with past findings and/or hypothesis made of convective initiation and dryline water vapor mixing ratio variations.