Exit jet in a narrow Pyrenean valley: the Aure Valley 2018 field experiment

A field experiment took place from July to October 2018 in a narrow valley of the central Pyrenees in order to study local flows and their impacts.
This field experiment is a joint effort by CNRM, Laboratoire d'Aerologie and University of the Balearic Islands. It emerged from a recent numerical study done by the University of the Balearic Islands (Jiménez et al. 2019).
This study suggests that under clear-sky conditions a jet forms in the valley and can be observed several kilometers away from the valley exit.

Several instruments including a Doppler scanning lidar and three meteorological stations were deployed on the main site at the valley exit, where the jet maximum is expected, and on two other sites up valley. Data from the Atmospheric Research Center (part of the Pyrenean Platform for the Observation of the Atmosphere P2OA) in Lannemezan are also used. They include radio-soundings specifically planned for the field experiment. This instrumented platform of Laboratoire d'Aerologie, located about 10 km away from the valley exit, is an important asset for the project.

An overview of the field experiment as well as the valley exit jet main features will be presented. A comparison with outputs from the NWP model AROME will be also shown.