Billmire Michael, French Nancy H F, Loboda Tatiana, Owen R Chris, Tyner Marlene
Michigan Tech Research Institute, 3600 Green Court Suite #100 Ann Arbor, MI 48105, USA.
Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA.
Int J Wildland Fire. 2014;23(8):1119-1129. doi: 10.1071/wf13046. Epub 2014 Nov 18.
Santa Ana winds have been implicated as a major driver of large wildfires in southern California. While numerous anecdotal reports exist, there is little quantitative analysis in peer-reviewed literature on how this weather phenomenon influences fire progression rates. We analysed fire progression within 158 fire events in southern California as a function of meteorologically defined Santa Ana conditions between 2001 and 2009. Our results show quantitatively that burned area per day is 3.5-4.5 times larger on Santa Ana days than on non-Santa Ana days. Santa Ana definition parameters (relative humidity, wind speed) along with other predictor variables (air temperature, fuel temperature, 10-h fuel moisture, population density, slope, fuel loading, previous-day burn perimeter) were tested individually and in combination for correlation with subsets of daily burned area. Relative humidity had the most consistently strong correlation with burned area per day. Gust and peak wind speed had a strong positive correlation with burned area per day particularly within subsets of burned area representing only the first day of a fire, >500 ha burned areas, and on Santa Ana days. The suite of variables comprising the best-fit generalised linear model for predicting burned area ( = 0.41) included relative humidity, peak wind speed, previous-day burn perimeter and two binary indicators for first and last day of a fire event.
圣安娜风被认为是南加州大型野火的主要驱动因素。虽然有许多轶事报道，但同行评审文献中关于这种天气现象如何影响火灾蔓延速度的定量分析很少。我们分析了2001年至2009年间南加州158起火灾事件中的火灾蔓延情况，将其作为气象定义的圣安娜风条件的函数。我们的结果定量显示，圣安娜风日的每日烧毁面积比非圣安娜风日大3.5至4.5倍。对圣安娜风的定义参数（相对湿度、风速）以及其他预测变量（气温、燃料温度、10小时燃料湿度、人口密度、坡度、燃料负荷、前一日燃烧周长）分别和组合进行测试，以确定与每日烧毁面积子集的相关性。相对湿度与每日烧毁面积的相关性最为一致且强烈。阵风风速和峰值风速与每日烧毁面积呈强正相关，特别是在仅代表火灾第一天的烧毁面积子集中、超过500公顷的烧毁面积以及圣安娜风日。用于预测烧毁面积（ = 0.41）的最佳拟合广义线性模型所包含的变量组合包括相对湿度、峰值风速、前一日燃烧周长以及火灾事件第一天和最后一天的两个二元指标。
