Retrieval of thermodynamic fields from multiple-Doppler radar data using the equations of motion and the thermodynamic equation.

Abstract

A new method is proposed to determine completely the thermodynamic fields from the relative pressure and temperature perturbations, retrieved from the processing of multiple-Doppler radar data through the equations of motion. A simplified thermodynamic equation is used to calculate the vertical gradients of the missing pressure and temperature constants. Then, provided that an initial value is known, the three-dimensional fields of pressure and temperature are deduced through adding, at each altitude, these constants to the relative pressure and temperature fields. This method is tested with dual-Doppler radar data from the observation of the frontal convective part of a West-African squall-line on 22 June 1981. A first attempt is made with two-dimensional data derived from the actual radar data and from the environmental winds. Then the method is applied to the actual three-dimensional fields. Vertical cross-sections of pressure and temperature perturbations are deduced, and the different components of the vertical projection of the equation of motion are analyzed. The different hypotheses and possible further improvements are finally discussed.-Author Centre de Recherches en Physique de l'Environ Terrestre, (CNET/CNRS), 92131 Issy-les-Moulineaux, France.