Climatology of Westerly Wind Events in the Lee of the Sierra Nevada
- Author(s)
- Stefano Serafin, Lukas Strauss, Vanda Grubisic
- Abstract
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(s)
- Department of Meteorology and Geophysics
- External organisation(s)
- National Center for Atmospheric Research (NCAR)
- Journal
- Journal of Applied Meteorology and Climatology
- Volume
- 56
- Pages
- 1003-1023
- No. of pages
- 21
- ISSN
- 1558-8424
- DOI
- https://doi.org/10.1175/JAMC-D-16-0244.1
- Publication date
- 04-2017
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105206 Meteorology
- Keywords
- ASJC Scopus subject areas
- Atmospheric Science
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/climatology-of-westerly-wind-events-in-the-lee-of-the-sierra-nevada(14bd93f5-d03b-4731-b133-7524a727235d).html