Climatology of Westerly Wind Events in the Lee of the Sierra Nevada

Autor(en)
Stefano Serafin, Lukas Strauss, Vanda Grubisic
Abstrakt

A 5-yr climatology of westerly wind events in Owens Valley, California, is derived from data measured by a mesoscale network of 16 automatic weather stations. Thermally driven up- and down-valley flows are found to account for a large part of the diurnal wind variability in this approximately north-south-oriented deep U-shaped valley. High-wind speed events at the western side of the valley deviate from this basic pattern by showing a higher percentage of westerly winds. In general, strong westerly winds in Owens Valley tend to be more persistent and to display higher sustained speeds than strong winds from other quadrants. The highest frequency of strong winds at the valley floor is found in the afternoon hours from April to September, pointing to thermal forcing as a plausible controlling mechanism. However, the most intense westerly wind events (westerly windstorms) can happen at any time of the day throughout the year. The temperature and humidity variations caused by westerly windstorms depend on the properties of the approaching air masses. In some cases, the windstorms lead to overall warming and drying of the valley atmosphere, similar to foehn or chinook intrusions. The key dynamical driver of westerly windstorms in Owens Valley is conjectured to be the downward penetration of momentum associated with mountain waves produced by the Sierra Nevada ridgeline to the west of the valley.

Organisation(en)
Institut für Meteorologie und Geophysik
Externe Organisation(en)
National Center for Atmospheric Research (NCAR)
Journal
Journal of Applied Meteorology and Climatology
Band
56
Seiten
1003-1023
Anzahl der Seiten
21
ISSN
1558-8424
DOI
https://doi.org/10.1175/JAMC-D-16-0244.1
Publikationsdatum
04-2017
Peer-reviewed
Ja
ÖFOS 2012
105206 Meteorologie
Schlagwörter
ASJC Scopus Sachgebiete
Atmospheric Science
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/climatology-of-westerly-wind-events-in-the-lee-of-the-sierra-nevada(14bd93f5-d03b-4731-b133-7524a727235d).html