Diagnosis and modelling of a summer convective storm over Mediterranean Pyrenees

摘要

Over the Mediterranean Pyrenees and near coastal region there is a highfrequency of convective storms during summertime. This fact determines alocal maximum of precipitation at this season unlike the normal and generalminimum over Mediterranean basin.

The common synoptic and mesoscale patterns associated to convectivephenomena are briefly analyzed and diagnosed with radar imagery, surfacepressure and isobaric level fields and surface data. They usually involves alittle distant through at medium levels, very weak pressure gradient at thesurface and not significant instability, but a preferred Planetary BoundaryLayer low-level convergence zones tied to the orography. As a result of thisanalysis two different kinds of circulations associated to recurrentconvergence zones have been recognized: upvalley/upslope winds and seabreezes.

High resolution simulations from a Numerical Weather Prediction model for acase study have carried out to analyze the role of the main key components,i.e. the orography, the sea and valley breeze and their influence togenerate local convergence zones. Furthermore, the skills of the model tosimulate the location and the intensity of the precipitation of these summerMediterranean storms have been discussed.