森林地表火行为估算的数学模型

本文在大量室内林火室验的基础上，通过参考ＢＥＨＡＶＥ程序中的数学模型，提出了一整套估算地表火火行为特征量的表达式。为保证求解火蔓延速度的更合理性和具有较高的精度，将风速和坡度对火蔓延速度的影响，采用了矢量叠加的方法进行修正。在假设火场为椭圆面来估算火场状况时，不但考虑了风速对火场形状的影响，还引入折合风达的概念，通过将坡度对火场的作用折合成相应的风速值来修正坡度的影响，与大兴安岭野外试验的结果对比表明，本数学模型定量合理。

A Mathematical Model for Estimating Surface Fire Behavior

Based on a great number of simulation exporiments of forest fire, and refered the mathemat-ical model in BEHAVE programme,a set of formulas for predicting surface fire bellavior havebeen established in this paper. To ensure a more rensonable fire spreading velocity with a relatively high accurcy,the ef-fect of windspeed and slope on fire spreading velocity are taken in to account with the mehted ofvector superposition. The burnt Zone is assumed to be ellipelti,for extimating the status of burntzone,while the effect of windspeed on burnt zone is also consltiered. Otherwlse,a concept of ef-fective windspeed is introduceed to modify the effect of slope, by converting the effect of slope on burnt zone into corresponding windspod. This model is quantitatively reasonable in comparison with resuIts of wildland tests in GreatXinan Mountains.