Three-Dimensional Multiple Doppler Radar Wind Synthesis and Thermodynamic Retrieval over Complex Terrain and Their Applications in Severe Weather Analyses

WInd Synthesis System using DOppler Measurements (WISSDOM) is a method designed to synthesize the three-dimensional winds over complex topography using data from multiple Doppler radars. The retrieved flow field from WISSDOM also satisfies the vertical vorticity equation, which makes it suitable for conducting thermodynamic retrieval.

In this study, a new scheme is developed to utilize the wind fields directly produced by WISSDOM to reconstruct the thermodynamic fields over mountainous area. A cost function containing the complete momentum equations and a simplified thermodynamic equation is formulated. Depending on whether a given grid point is located above or below the terrain surface, different variational codes are written. Through minimizing the cost function, one can recover the three-dimensional thermodynamic fields over terrain.

A series of idealized tests are conducted to investigate the performance of the new retrieval scheme in recovering three-dimensional pressure and temperature fields under different scenarios, ranging from dry to moist environments, with single or multiple mountains. The new retrieval scheme is then applied to a real case study from IOP#8 of SouthWest Monsoon EXperiment (SoWMEX) held in 2008 in Taiwan. It is shown that the kinematic and thermodynamic fields of a heavy precipitation system influenced by Taiwan’s terrain can be revealed by high resolution observed and retrieved meteorological fields.