Abstract : A.4
A comparison between two katabatic flows of different length-scale in mid-latitudes

Daniel Martínez, Antoni Mira, Joan Cuxart
Universitat Illes Balears (UIB)

An analysis of the dynamics of two different length-scale katabatic flows is made. The analyzed data is provided by two high resolution mesoscale simulations of the northern Spanish plateau and of the isle of Majorca, in Western Mediterranean sea. Both locations are in middle latitudes but with a different topographical context. The first simulation is run over a large-scale almost closing basin (Duero), while the other corresponds to a small island with complex terrain. Every simulation is verified using available data from the meteorological network and the surface radiative temperature estimated from satellites. A densely instrumented 100m-tower located within the Duero basin is also used for the first case.

A two-layer model following the framework set out in Marht (1982) is applied to study the vertically integrated downslope momentum budget. Therefore, the relevancy of each forcing term is estimated and the evolution of the bulk variables of both gravity flows are studied along the slopes and over time. The same methodology is applied as well to the thermodynamic equation. Finally, the application of the bulk model leads to an objective comparison between the two different katabatic flows.