Four-dimensional assimilation of multitime wind profiles over a single station and numerical simulation of a mesoscale convective system observed during IHOP_2002

Abstract

This study examines the impact of assimilating multitime wind profiles over a single station on the numerical simulation of a warm season mesoscale convective system over the region from the Kansas and Oklahoma border to the Texas Panhandle, observed 12-13 June 2002 during the International H 2O Project (IHOP_2002). Wind profile observations, obtained from Goddard Lidar Observatory for Winds (GLOW) are assimilated into an advanced research version of the Weather Research and Forecasting (WRF) model using its four-dimensional variational data assimilation (4DVAR) system. Results indicate that the assimilation of high temporal and vertical resolution GLOW wind profiles has a significant influence on the numerical simulation of the convective initiation and evolution. Besides the wind fields, the structure of the moisture fields associated with the convective system is also improved. Data assimilation has also resulted in a more accurate prediction of the locations and timing of the convection initiations; as a consequence, the skill of quantitative precipitation forecasting is enhanced greatly. The positive impact of 4DVAR assimilation of multitime wind profiles over a single station on the mesoscale prediction in this study presents a successful procession of the traditional technique in time to space conversion. However, when the data from conventional networks are assimilated into the model withGLOW wind profiles, the data impact is not compatible with that from the assimilation of GLOW wind profiles only, implying the need for a high temporal and spatial resolution wind profile network in order to achieve reasonable mesoscale analysis and forecasting. © 2011 American Meteorological Society.