Using Radar Wind Observations to Improve Mesoscale Numerical Weather Prediction

Abstract

A high-resolution radar data assimilation system is presented for high-resolution numerical weather prediction models. The system is under development at the Naval Research Laboratory for the Navy’s Coupled Ocean–Atmosphere Mesoscale Prediction System. A variational approach is used to retrieve three-dimensional dynamical fields of atmospheric conditions from multiple-Doppler radar observations of radial velocity within a limited area. The methodology is described along with a preliminary evaluation of the impact of assimilated radar data on model forecasts using a case study of a squall line that occurred along the east coast of the United States on 9 May 2003. Results from the experiments show a significant impact from the assimilated radar radial velocity data on the model forecast of not just dynamical but also hydrological fields at all model levels for the duration of the storm. A verification system has also been developed to assess the radar data assimilation impact, and the results show improvements in the three-dimensional wind forecasts but relatively small changes in the prediction of storm locations. This study highlights the need to develop a continuous radar data assimilation system to maximize the impact of the data.

Impact of radar data assimilation for the simulation of a heavy rainfall case in central Italy using WRF–3DVAR

“…Another variational-based radar data assimilation system was developed by Gao et al (2004) using a three-dimensional variational data assimilation (3DVAR) technique in the framework of the ARPS (Advanced Research and Prediction System, Xue et al, 2003) model. A so-called 3.5-dimensional variational radar data assimilation based on the navy's COAMPS (Coupled Ocean/Atmosphere Mesoscale Prediction System) was developed and verified through a number of studies (Zhao et al, 2006;Xu et al, 2010). These variational systems showed great potential in the use of radar observations for initializing high-resolution numerical models through several case studies and real-time demonstrations (Sun et al, 2010;Xue et al, 2010).…”

High-Resolution Radar Data Assimilation for Hurricane Isabel (2003) at Landfall

“…These retrieved fields are then assimilated into the COAMPS model to improve the mesoscale and storm-scale dynamical and thermodynamic features in the model initial fields. Results from our previous study of a squall line case (Zhao et al 2006) showed a major impact of radar wind data assimilations on storm predictions. Recently, the system has been enhanced with new capabilities to assimilate radar reflectivity data along with radar radial velocity observations to improve the characterization of both the dynamical and microphysical structures of storms in model initial conditions.…”

Wind turbine impact on operational weather radar I/Q data: characterisation and filtering

“…Data from weather radars are, for example, used by meteorologists to follow the weather in real time, as input to numerical weather prediction models (e.g. Sun and Wilson, 2003;Xue et al, 2003;Zhao et al, 2006), and to drive hydrological models (e.g. Corral et al, 2000;Carpenter et al, 2001;Ganguly and Bras, 2003;Gourley and Vieux, 2005).…”