Sensitivity Experiments of the Local Wildland Fire with WRF-Fire Module
Sensitivity Experiments of the Local Wildland Fire with WRF-Fire Module
复制标题
WRF-Fire模块对局部荒地火灾的敏感性实验
DOI：
10.1007/s13143-019-00160-7
复制
发表时间：
2019
影响因子：
2.3
通讯作者：
Weijie Wu
中科院分区：
文献类型：
--
作者：
Shaojun Lai;Haishan Chen;Fen He;Weijie Wu
本文利用2012年3月6日在新泽西松林荒地（NJPB）进行的一次低强度规定火（LIPF）实验中收集的观测数据，讨论了天气研究与预报（WRF）模型与荒地火行为模块（WRF-Fire模型）耦合的性能。利用WRF-Fire模式进行了野外林火与大气边界层相互作用的敏感性试验。采用火灾和大涡模拟（LES）模式相结合的双向WRF-Fire模型，探讨了火灾的周界形状、强度、蔓延方向和风速等外界因素对火灾的影响，以及大气与火灾的相互作用。结果表明，敏感性实验能够提供火点附近近地面的温度、风速和湍流动能等与观测值接近的气象要素。模拟还可以再现火灾蔓延的形状和速度，火灾强度，以及从火灾释放的热通量。从能量的角度看，热通量反馈到大气模式中，加热近地面空气，诱发强烈的热力和动力不稳定，引起强烈的水平辐合和上升气流，形成火致对流边界层。上升气流将根据环境风的高度倾斜到火灾区域的下游。由于这种上升气流的作用，燃料燃烧产生的颗粒和热量可以被输送到火灾区域的下风和侧部区域。同时，火线附近存在动量较大的下降气流，将新鲜氧气输送到近地表，这将增加火线后方的风力，加快蔓延速度（ROS），使火势蔓延到更大的区域。最终，形成了一种由火引起的气候。
In this paper, it is discussed the performance of the Weather Research and Forecasting (WRF) model coupled with a wildland fire-behavior module (WRF-Fire model) by the observational data collected in an experiment with a low-intensity prescribed fire (LIPF) conducted in the New Jersey Pine Barrens (NJPB) on March 6, 2012. The sensitivity experiments of the WRF-Fire model are carried out to investigate the interactions between the wildland fire and the atmospheric planetary boundary layer. The two-way WRF-Fire model conofigured with fire and large eddy simulation (LES) mode is used to explore the fire characteristics of perimeter shape, intensity, spread direction and external factors of wind speed, and to discuss how these external parameters affect the fire, and the interactions between the atmosphere and fire. Results show that the sensitive experiments can provide the meteorological elements close to observations, such as the temperatures, winds and turbulent kinetic energy near the surface in the vicinity of the fire. The simulations also can reproduce the fire spread shape and speed, fire intensity, and heat flux released from fire. From the view of energy, the heat flux feed back to the atmospheric model and heat the air near the surface, which will induce strong thermal and dynamic instability causing strong horizontal convergence and updraft, and form the fire-induced convective boundary layer. The updraft will be tilted downstream of the fire area based on the height of the ambient winds. Due to the effect of the this updrafts, the particles and heat from the fuel combustion can be transported to the downwind and lateral regions of the fire area. Meanwhile, there is a downdraft flow with higher momentum nearby the fire line transporting fresh oxygen to the near surface, which will increase winds behind the fire line, accelerate the rate of spread (ROS) and make the fire spread to a larger area. Ultimately, a fire-induced climate is established.