基于Rothermel模型的可燃物参数对林火行为影响的计算机仿真

Effects of fuel load and height on accuracy of fi re simulation: a case study of 4.30 Nnuohanhe conf lagration in Great Khingan region, Heilongjiang province

提高模拟的精度是林火行为模拟研究的重要目标。对大火场的模拟研究中,可燃物信息准确性对火行为模拟精度的研究还不充分、系统。为此,本文以大兴安岭地区4.30罕诺河大火作为研究对象,利用自主开发的、基于Rothermel模型的、可进行多次循环模拟的林火行为模拟程序,共进行了3 072次不同可燃物载量和高度组合的林火模拟实验,以揭示可燃物载量和床层高度对大火场模拟精度的影响。研究结果表明:载量对模拟精度的影响是有限的。其中,草甸可燃物载量对模拟精度影响较小,森林和灌丛可燃物载量使Kappa系数值增加2%左右。草甸可燃物床层高度对模拟精度影响较大,可使Kappa系数值增加0.04;森林可燃物床层高度对模拟精度影响最大,其床层高度增加可使Kappa系数数值增加超过0.17,3 072次林火蔓延模拟中,在不同载量和床层高度组合下,Kappa系数均值为0.16,最大值为0.206;灌丛高度对模拟精度影响不大;这些模拟火场与真实火场的一致性还是很低。

Improving simulation accuracy is an important goal of fire behavior simulation study. Research on the influence of collected fuel information accuracies on fire simulation is still inadequate. The Nuohanhe Conflagration burned on April 30, 2007 in Daxinganling Region, Heilongjiang Province was chosen to study the influence of fuel-bed load and height on fire simulation accuracy. Totally 3072 simulations were conducted with different combinations of fuel-bed load and height using a program developed based on Rothermel model. This program allows multiple simulations conducted automatically without the labor of entering parameters for each simulation each time by hand. Kappa coefficient was used to evaluate the accuracy of the simulations. The results indicate that the fuel load exerted the limited influence on simulation accuracy; Load of grass had little influence on simulation and those of bush and forest fuel could increased Kappa coefficient by 0.02; But that of grass fuel could increased Kappa coefficient by 0.04; Height of forest fuel had the maximum influence on simulation; Increasing height of forest fuel could increased Kappa coefficient by more than 0.17; The mean and maximum Kappa coefficient of all the 3072 simulations were 0.16 and 0.206; Height of bush fuel did not affect simulation accuracy very much, which indicated that the consistency between real fire and simulated fire was poor.