|Title||Santa Ana Winds of Southern California: Their climatology, extremes, and behavior spanning six and a half decades|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Guzman-Morales J., Gershunov A, Theiss J., Li H.Q, Cayan D|
|Journal||Geophysical Research Letters|
|Type of Article||Article|
|Keywords||Climate variability; extremes; oscillation; reanalysis; regimes; regional weather; Santa Ana Winds; variability|
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.
Under climate change, the Great Basin is projected to warm faster than the coastal region, which suggests that SAW occurrence may diminish [Hughes et al., 2011]. However, the reconstructed historical record of SAWs does not thus far support such expectation. Instead, it raises new questions about future SAWs and fire seasons. The only long-term trend that we observe is in the extremes of SAWs, which appears to be related to the mid-1970s North Pacific climate shift....Our empirical results suggest that seasonal ENSO-related prediction of SAW activity and fire risk may be possible, a topic for further investigation. These results taken together with the known sensitivity of regional hydroclimate to global climate change [Polade et al., 2014], warrant a fresh look at climate change projections of SAWs, precipitation regime and fire risk.