Title

On The Use Of Profiler Data In Limited-Area Numerical Weather Prediction (variational Analysis Technique, Initialization)

Date of Award

1986

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Meteorology and Physical Oceanography

Abstract

The feasibility of running a limited-area numerical weather prediction model with initial conditions from a network of profilers is investigated. The observing system, a combination of microwave radiometer and UHF/VHF Doppler radar, provides low-resolution vertical temperature profiles and highly accurate wind measurements. The initial fields are created by a 12-hour model run. The high-resolution wind field is represented by the model output, simulating a network with profilers located at every grid point of the model domain. The model-created temperature field has to be smoothed vertically and horizontally to match the accuracy of the radiometer observations. A variational analysis technique is applied to infer the missing frontal-scale thermal structure in the three-dimensional temperature field from the more accurate wind observations. A double twin experiment is carried out, using an isentropic primitive equation model. First, the model is initialized with the smooth temperature field and the model-created wind field. Second, the model is initialized with the variationally analyzed mass field and the associated wind field. The two forecasts are compared to a control forecast.Four different synoptic cases are chosen to investigate the impact of smooth and upgraded mass fields on the numerical weather forecast: a cold air outbreak in January 1985, two springtime cyclogenesis events which took place in March 1983 and in April 1982, and one severe weather event which occurred in June 1983.

Keywords

Physics, Atmospheric Science

Link to Full Text

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