Publications

Export 2 results:
Sort by: Author Title Type [ Year  (Desc)]
2016
Guzman-Morales, J, Gershunov A, Theiss J, Li HQ, Cayan D.  2016.  Santa Ana Winds of Southern California: Their climatology, extremes, and behavior spanning six and a half decades. Geophysical Research Letters. 43:2827-2834.   10.1002/2016gl067887   AbstractWebsite

Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region, but their climate-scale behavior is poorly understood. In the present work, we identify SAWs in mesoscale dynamical downscaling of a global reanalysis from 1948 to 2012. Model winds are validated with anemometer observations. SAWs exhibit an organized pattern with strongest easterly winds on westward facing downwind slopes and muted magnitudes at sea and over desert lowlands. We construct hourly local and regional SAW indices and analyze elements of their behavior on daily, annual, and multidecadal timescales. SAWs occurrences peak in winter, but some of the strongest winds have occurred in fall. Finally, we observe that SAW intensity is influenced by prominent large-scale low-frequency modes of climate variability rooted in the tropical and north Pacific ocean-atmosphere system.

2010
Bytnerowicz, A, Cayan D, Riggan P, Schilling S, Dawson P, Tyree M, Wolden L, Tissell R, Preisler H.  2010.  Analysis of the effects of combustion emissions and Santa Ana winds on ambient ozone during the October 2007 southern California wildfires. Atmospheric Environment. 44:678-687.   10.1016/j.atmosenv.2009.11.014   AbstractWebsite

Combustion emissions and strong Santa Ana winds had pronounced effects on patterns and levels of ambient ozone (O(3)) in southern California during the extensive wildland fires of October 2007. These changes are described in detail for a rural receptor site, the Santa Margarita Ecological Reserve, located among large fires in San Diego and Orange counties. In addition, O(3) changes are also described for several other air quality monitoring sites in the general area of the fires. During the first phase of the fires, strong, dry and hot northeasterly Santa Ana winds brought into the area clean continental air masses, which resulted in minimal diurnal O(3) fluctuations and a 72-h average concentration of 36.8 ppb. During the- second phase of the fires, without Santa Ana winds present and air filled with smoke, daytime O(3) concentrations steadily increased and reached 95.2 ppb while the lowest nighttime levels returned to similar to 0 ppb. During that period the 8-h daytime average O(3) concentration reached 78.3 ppb, which exceeded the federal standard of 75 ppb. After six days of fires, O(3) diurnal concentrations returned to pre-fire patterns and levels. Published by Elsevier Ltd.