Summer Midlatitude Stationary Wave Patterns Synchronize Northern Hemisphere Wildfire Occurrence
Summer Midlatitude Stationary Wave Patterns Synchronize Northern Hemisphere Wildfire Occurrence
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DOI：
10.1029/2022gl099017
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发表时间：
2022-09-28
影响因子：
5.2
通讯作者：
Wieder, William R.
中科院分区：
文献类型：
--
作者：
Bui, Hien X.;Timmermann, Axel;Wieder, William R.
中纬度定常波是大气环流中相对持久的大尺度经向变化。尽管最近的案例研究表明驻波和极端天气事件之间存在密切联系，但人们对驻波和野火活动之间的全球范围联系以及这种关系在温暖气候中的潜在变化知之甚少。在这里，通过分析社区地球系统模型版本2大合奏，我们表明，纬向波数5-6驻波模式往往同步野火发生在整个北方半球中纬度地区。对流层上部脊和槽的交替产生了一个半球尺度的空间格局交替热/干和冷/湿的条件下，这增加或减少野火的发生，分别。更持久的高压条件大大增加野火的可能性。尽管这些波动的动力学响应于人为全球变暖的变化很小，但由于气候背景条件的变化，相应的中纬度野火变化预计将加剧。简明语言摘要野火是经常引起严重公共紧急事件的自然灾害。提高我们预测野火发生的能力有可能减少与之相关的生命和财产损失。在这项研究中，我们分析了新的大集合模拟进行的社区地球系统模式，版本2在1度分辨率，以阐明大气驻波和集群北方半球野火发生之间的联系，以及在这种关系的潜在变化，在温暖的气候。我们的分析表明，野火发生往往以纬向波数5-6驻波模式在区域上聚集。更持久的区域高压条件进一步增加野火的可能性。这种关系在很大程度上可以用与夏季中纬度波列有关的准定常湿度和相对湿度条件来解释。更持久的区域高压条件进一步增加了野火发生的可能性。
Midlatitude stationary waves are relatively persistent large-scale longitudinal variations in atmospheric circulation. Although recent case studies have suggested a close connection between stationary waves and extreme weather events, little is known about the global-scale linkage between stationary waves and wildfire activity, as well as the potential changes in this relationship in a warmer climate. Here, by analyzing the Community Earth System Model version 2 large ensemble, we show that a zonal wavenumber 5-6 stationary wave pattern tends to synchronize wildfire occurrences across the Northern Hemisphere midlatitudes. The alternation of upper-troposphere ridges and troughs creates a hemispheric-scale spatial pattern of alternating hot/dry and cold/wet conditions, which increases or decreases wildfire occurrence, respectively. More persistent high-pressure conditions drastically increase wildfire probabilities. Even though the dynamics of these waves change little in response to anthropogenic global warming, the corresponding midlatitude wildfire variability is projected to intensify due to changes in climate background conditions.Plain Language Summary Wildfires are natural disasters that often cause severe public emergencies. Increasing our ability to predict wildfire occurrence has the potential to reduce the loss of life and property associated with them. In this study, we analyze new large-ensemble simulations conducted with the Community Earth System Model, version 2 in 1 degree resolution to elucidate the linkage between atmospheric stationary waves and clustered Northern Hemisphere wildfire occurrences, as well as the potential changes in this relationship in a warmer climate. Our analysis shows that wildfire occurrences tend to be clustered regionally by a zonal wavenumber 5-6 stationary wave pattern. More persistent regional high-pressure conditions further increase wildfire probabilities. This relationship can be largely explained by the quasi-stationary moisture and relative humidity conditions which are associated with the summer midlatitude wave trains. More persistent regional high-pressure conditions further increase likelihood of wildfire occurrences.