Two-dimensional structure of mountain wave observed by aircraft during the PYREX experiment

J. L. Attié, A. Druilhet, P. Durand, B. Bénech
1997 Annales Geophysicae  
This study presents an experimental analysis from aircraft measurements above the Pyrenees chain during the PYREX experiment. The Pyrenees chain, roughly WE oriented, is a major barrier for northerly and southerly air¯ows. We present a case of southerlȳ ow (15 October 1990) and three successive cases of northerly¯ows above the Pyrenees (14, 15 and 16 November 1990) documented by two aircraft. The aircraft have described a vertical cross section perpendicular to the Pyrenean ridge. This area is
more » ... idge. This area is described via the thermodynamical and dynamical ®elds which have a horizontal resolution of 10 km. Three methods for computing the vertical velocity of the air are presented. The horizontal advection terms which play a role in the budget equations are also evaluated. The altitude turbulence zone of 15 October are shown via turbulent uxes, turbulent kinetic energy (TKE), dissipation rate of TKE and inertial length-scale. A comparison of results obtained by eddy-correlation and inertial-dissipation method is presented. The experimental results show a warm and dry downdraft for the southerly¯ow with large values for advection terms. All the mountain wave cases are also shown to present an important dynamical perturbation just above the Pyrenees at upper altitudes.
doi:10.1007/s005850050501 fatcat:xj3uowoc45ecbpulkjbmokprjy