Slope and basin flows in the Ebro basin: conditioned climatology and mesoscale modelling

To characterize the boundary layer evolution in complex terrain, the assumption of

horizontal homogeneity does not apply and the understanding of slope and basin flows is a

necessity. Here a double fold approach is made. On one hand, a ten-year climatology is

made for an ensemble of stations in the Lleida area of the Ebro basin, with a typical

separation of 10 kilometers between stations. The climatology is restricted to stably

stratified nights and an effort has been made to develop suitable filters for the

database. Interpretation of the statistics with time along night and situation gives

hints on the flow patterns within the basin.

On the other hand, a high resolution mesoscale simulation is made for a clear skies night

with weak synoptic winds, in the hope that it reproduces the typical basin circulations

during that night. Comparison with the data for that night, radiative surface temperature

from satellite and the conditioned climatology will be used for validation and inspection

of the model outputs to understand the slope and basin flows.