Simulations of Mesoscale Circulations in the Center of the Iberian Peninsula for Thermal Low Pressure Conditions. Part I: Evaluation of the Topography Vorticity-Mode Mesoscale Model

Abstract

The Topography Vorticity-Mode Mesoscale (TVM) model has been evaluated for four different cases of thermal low pressure systems over the Iberian Peninsula. These conditions are considered to be representative of the range of summer thermal low pressure conditions in this region. Simulation results have been compared with observations obtained in two intensive experimental campaigns carried out in the Greater Madrid Area in the summer of 1992. The wind fields are qualitatively well simulated by the model. Detailed comparisons of the time series of simulations and observations have been carried out at several meteorological stations. For wind speed and direction, TVM results are reasonably good, although an underprediction of the daily thermal oscillation has been detected. The model reproduces the observed decoupled flow in the nighttime and early morning along with the evolution of mixing layer flow during the day. In addition, the model has simulated specific features of the observed circulations such as low-level jets and drainage, downslope, upslope, and upvalley flows. The model also simulates the formation of hydrostatic mountain waves in the nighttime in some cases.