Prediction of Thunderstorm Initiation Through 4-Dimensional Data Assimilation of Doppler Radar Data

Real-Data Tests of a Single-Doppler Radar Assimilation System

“…As was shown in Cotton et al (1989), nudging the winds alone in this situation may actually create a cold anomaly through adiabatic cooling, resulting in the circulation reversing direction after the nudging is stopped. Our own assimilation experiments using wind data alone (Hamill, 1992) for a seabreeze simulation also showed generally inferior forecasts compared to those experiments with nudging to observed winds and temperatures.…”

“…The first report in the series (Hamill, 1992) describes the forecast model used in this study (PL3D -a hydrostatic version of the Colorado State University Regional Atmospheric Modeling System (CSU RAMS)) and the results of observing system simulation experiments demonstrating the importance of assimilating wind and temperature data, rather than just wind data. This confirmed the results by Liou (1989) and Cotton et al (1989) that assimilation using Newtonian nudging (Stauffer and Seaman, 1990) of the observed Doppler wind velocities alone is usually insufficient; temperature information is also needed.…”