The Inn Valley exit jet: results of the TEAMx pre-campaign
- 1German Meteorological Service, Munich, Germany (katrin.sedlmeier@dwd.de)
- 2German Meteorological Service, Offenbach, Germany
- 3German Meteorological Service, Lindenberg Meteorological Observatory, Lindenberg, Germany
Previous studies have found a pronounced nocturnal low-level jet at the exit of the Inn Valley north of the valley contraction near Schwaigen which reaches into the Alpine foreland (e.g. Pamperin and Stilke, 1985 as part of the MERKUR experiment or a model study by Zängl, 2004). The exit jet forms under nocturnal stably stratified atmospheric conditions and is interpreted as a transition from subcritical to supercritical hydraulic flow.
As part of the pre-campaign of the TEAMx programme in June-August 2022, we have conducted measurements to corroborate the previous findings on the formation and maintenance of the Inn valley exit jet and learn more about its turbulence structure, which has not been studied in previous experiments. For this purpose, a wind lidar was deployed in Brannenburg, north of the valley constriction. TKE profiles were derived from the Lidar measurements using the method described in Smalikho and Banakh (2017). Furthermore, 3-hourly radiosondes were launched at the site of the wind lidar, accompanied by drone measurements during an IOP (18/19 July 2022) in high pressure weather conditions with low cloud cover.
Upper air and surface wind measurements during the IOP captured a well pronounced Inn valley exit jet which is analyzed in detail in this contribution. Additionally, a statistical analysis of the occurrence and characteristics of nocturnal low-level jets within the whole pre-campaign period is presented.
References:
TEAMx: http://www.teamx-programme.org/
Smalikho, I.N., and V.A. Banakh. "Measurements of wind turbulence parameters by a conically scanning coherent Doppler lidar in the atmospheric boundary layer." Atmospheric Measurement Techniques 10.11 (2017): 4191-4208.
Pamperin, H., and G. Stilke. "Nächtliche Grenzschicht und LLJ im Alpenvorland nahe dem Inntalausgang." Meteorologische Rundschau 38.5 (1985): 145-156
Zängl, G. "A reexamination of the valley wind system in the Alpine Inn Valley with numerical simulations." Meteorology and Atmospheric Physics 87.4 (2004): 241-256.
How to cite: Sedlmeier, K., Kossmann, M., Paunovic, I., Eichhorn-Müller, A., Nitsche, O., Leinweber, R., Päschke, E., and Mühlbacher, G.: The Inn Valley exit jet: results of the TEAMx pre-campaign, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12631, https://doi.org/10.5194/egusphere-egu24-12631, 2024.
