An Observational Study of the Inn Valley Exit Jet in Southern Germany

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ABSTRACT The Inn Valley exit jet (VEJ) is a frequently occurring nocturnal wind phenomenon in the exit region of the Inn Valley, north of a valley constriction before the valley broadens into the foreland. Using upper‐air and surface measurements conducted during the pre‐campaign of the TEAMx programme in June–August 2022, we found new insights on the structure of the VEJ, especially its turbulence properties, as well as on the effects of the jet at the surface level. During the TEAMx pre‐campaign, VEJs occurred in 47 of the 93 nights considered and showed similar characteristics in all jet nights. Wind speeds during nocturnal VEJ events are strongest between 04:00 and 06:00 UTC, with medians between 10 and 11 m/s and maxima of up to 19 m/s at 100–200 m AGL. Below and above the jet height, shear‐induced turbulence is found. The jets clearly influence the wind field, temperature and turbulence at the surface level, with a clear rise/drop in wind speeds and TKE during the onset/decay of the jet.

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