Synoptic Classification of the Mixed-Layer Height Evolution

Abstract

Around 270 meteorological soundings launched during 1991 and 1992 in the Madrid basin have been studied. Using the vertical profiles of the main meteorological variables obtained from these soundings, an analysis of mixed-layer (ML) height evolution has been carried out. It has been found that the synoptic conditions exert a strong influence on the daily ML evolution, type of mixing, and maximum ML height. The mechanical and convective contributions to the ML development have been analyzed considering a synoptic classification of weather types affecting the Iberian Peninsula. For each weather type, the mean ML evolution along the day has been estimated using a nonlinear regression model. The results have shown that the diurnal variability of the mechanical mixing heights is substantially small compared with the convective ML evolution. In addition, the temporal ML growth from the daily minimum to the daily maximum has been calculated for each synoptic type. Finally, a stepwise variable procedure has been used to determine the main meteorological variables involved in the ML development processes under cloud cover and clear sky conditions.