Download or read book Climate Change-projected Santa Ana Fire Weather Occurrence written by and published by . This book was released on 2006 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new approach for detecting foehn [Föhn] weather conditions, such as the Santa Ana occurrence (SAO), was performed using two Atmosphere-Ocean General Circulation Models, the GFDL and the PCM, forced with the relatively high (A2) and low (B1) greenhouse gas emissions detailed in the IPCC Special Report on Emission Scenarios. Southern California Santa Ana winds were analyzed using large-scale pressure gradients and humidity fields. Results indicate a good correlation between large-scale detected Santa Ana occurrences and observed offshore winds during periods of low humidity. The sensitivity of the number of climate change-projected SAOs was analyzed for three future time periods -- 2005-2035, 2035-2064, 2070-2099 -- and ranged from 26% to 138% of historical. GFDL A2 and B1 outcomes indicate that the warmest fall month, September, has an increase in SAO days in the early part of this century, followed by a decrease, while the PCM A2 and B1 outcomes suggest fewer SAOs during September. Meanwhile, the strongest historical SAO month, December, experiences SAO decreases for all cases during 2005-2034 and increases for 2070-2099. This initial analysis suggests that Santa Ana conditions may significantly increase during California's fire season, but in general are unlikely to be radically more or less frequent than at present.