Observations of Turbulent Heat and Momentum Fluxes during Wildland Fires in Forested Environments
Observations of Turbulent Heat and Momentum Fluxes during Wildland Fires in Forested Environments
复制标题
森林环境中野火期间湍流热和动量通量的观测
DOI：
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发表时间：
2019
影响因子：
3
通讯作者：
S. Zhong
中科院分区：
文献类型：
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作者：
W. Heilman;X. Bian;K. Clark;S. Zhong
野火附近的热和动量的湍流通量有助于火灾环境中的热和动量的重新分配，这反过来又会影响燃料的加热，火灾行为和烟雾扩散。作为以前的观测研究在森林环境中的荒地火灾附近的湍流制度的延伸，本研究探讨了蔓延的地表火灾和森林上层植被的湍流热量和动量通量从近地表附近的上层植被的顶部附近的影响。配置文件的高频（10 Hz）的风速和温度测量在两个规定的火灾实验被用来评估的相对贡献的水平和垂直湍流通量的热量和动量的总热量和动量通量场。的湍流热通量和动量通量的频率依赖的时间变化之前，期间，和之后的火前通道也检查使用共谱分析。研究结果突出了地表荒地火灾和森林植被的影响，集体可以在火灾附近的湍流热量和动量通量的时间和垂直变化和热和动量cospectrum的实质性偏离典型的大气表面层cospectrum，可以发生之前，期间和之后火锋通道。
Turbulent fluxes of heat and momentum in the vicinity of wildland fires contribute to the redistribution of heat and momentum in the fire environment, which in turn can affect the heating of fuels, fire behavior, and smoke dispersion. As an extension of previous observational studies of turbulence regimes in the vicinity of wildland fires in forested environments, this study examines the effects of spreading surface fires and forest overstory vegetation on turbulent heat and momentum fluxes from near the surface to near the top of the overstory vegetation. Profiles of high-frequency (10 Hz) wind velocity and temperature measurements during two prescribed fire experiments are used to assess the relative contributions of horizontal and vertical turbulent fluxes of heat and momentum to the total heat and momentum flux fields. The frequency-dependent temporal variability of the turbulent heat and momentum fluxes before, during, and after fire-front passage is also examined using cospectral analyses. The study results highlight the effects that surface wildland fires and forest overstory vegetation collectively can have on the temporal and vertical variability of turbulent heat and momentum fluxes in the vicinity of the fires and the substantial departures of heat and momentum cospectra from typical atmospheric surface-layer cospectra that can occur before, during, and after fire-front passage.