Relationships between climate and macroscale area burned in the western United States
Relationships between climate and macroscale area burned in the western United States
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DOI：
10.1071/wf13019
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发表时间：
2013-01-01
影响因子：
3.1
通讯作者：
Kolden, Crystal A.
中科院分区：
文献类型：
--
作者：
Abatzoglou, John T.;Kolden, Crystal A.
近几十年来，美国西部野火活动（例如起火次数、烧毁面积、火灾行为）的增加，提高了人们对解决气候与火灾关系的兴趣。美国西部八个地理区域协调中心利用从烧伤严重程度监测趋势数据集（1984-2010 年）得出的烧毁面积，对森林和非森林土地的宏观气候与火灾关系进行了研究。除了每月温度、降水和干旱指数的标准气候变量之外，还考虑了火灾特定的生物物理变量，包括火灾危险和水平衡指标，以明确确定其解释烧毁面积年际变化的最佳能力。与火灾季节前或火灾季节期间的标准变量相比，与燃料和土壤湿度耗尽以及火灾危险长期升高相关的生物物理变量与燃烧面积的相关性更强，特别是在森林系统中。先前的气候与火灾关系表现出区域间的共性，林地烧毁面积与冬季雪水当量和晚春的紧急干旱相关。非林地烧毁面积与火灾年份前生长季节的水分供应量相关。尽管前期气候在预处理燃料方面的作用存在差异，但森林和非森林土地同步的区域火灾活动表明，火灾季节的大气条件统一了火灾活动，并且可以复合或取代前期的气候压力源。总的来说，通过生物物理变量的视角观察的气候-火灾关系比标准气候变量提供了与燃料可燃性和野火活动更直接的联系，从而缩小了经验火灾模型和基于过程的火灾模型之间自上而下的气候因素之间的差距。
Increased wildfire activity (e.g. number of starts, area burned, fire behaviour) across the western United States in recent decades has heightened interest in resolving climate-fire relationships. Macroscale climate-fire relationships were examined in forested and non-forested lands for eight Geographic Area Coordination Centers in the western United States, using area burned derived from the Monitoring Trends in Burn Severity dataset (1984-2010). Fire-specific biophysical variables including fire danger and water balance metrics were considered in addition to standard climate variables of monthly temperature, precipitation and drought indices to explicitly determine their optimal capacity to explain interannual variability in area burned. Biophysical variables tied to the depletion of fuel and soil moisture and prolonged periods of elevated fire-danger had stronger correlations to area burned than standard variables antecedent to or during the fire season, particularly in forested systems. Antecedent climate-fire relationships exhibited inter-region commonality with area burned in forested lands correlated with winter snow water equivalent and emergent drought in late spring. Area burned in non-forested lands correlated with moisture availability in the growing season preceding the fire year. Despite differences in the role of antecedent climate in preconditioning fuels, synchronous regional fire activity in forested and non-forested lands suggests that atmospheric conditions during the fire season unify fire activity and can compound or supersede antecedent climatic stressors. Collectively, climate-fire relationships viewed through the lens of biophysical variables provide a more direct link to fuel flammability and wildfire activity than standard climate variables, thereby narrowing the gap in incorporating top-down climatic factors between empirical and process-based fire models.