基于风速随机变量的植物种子风传播距离概率模型

Probability Model of Plant Seed Dispersal Distance by Wind

种子风传播过程是植被地理分布及其对环境变化响应的关键.植物种子风传播距离是种子风传播能力的重要特征.建立种子风传播距离模型对准确预测植被地理分布变化十分关键.首先基于物理学中动力学原理,推导出了种子风传播动力学方程,基于风速对数正态分布和维布尔分布模式,推导出了植物种子风传播距离概率模型,并给出了计算步骤.同时,以6种蒲公英为例,分析了不同植物在不同地点和不同月份种子风传距离的概率密度特征.算例表明,不同植物、不同地点和不同时间种子风传播距离概率密度不同,并且种子风传播距离概率密度在风速为对数正态分布下比维布尔分布下要高,传播距离概率密度较高最大传播距离在维布尔分布下比对数正态分布下要远.未来研究种子风传播距离模型需要考虑近地面层空气动力学参数和风速分布其它模式.

The process of seed dispersal by wind is the key to the geographical distribution of vegetation and its response to environmental changes.The distance of seed dispersal by wind is an important feature of seed dispersal by wind.The establishment of distance model of seed dispersal by wind is very important for accurately forecasting the change of geographical distribution of vegetation.Based on the kinetic principle of the physics,this paper derived the seed dispersal kinetics equation by wind.Based on the Logarithmic normal distribution of wind speed and the Weibull distribution of wind speed,two probability models of wind dispersal distance by wind are derived and the calculation steps are pointed out.At the same time,the probability density characteristics of different species in different locations and different months were analyzed by using 6 kinds of dandelions.The results show that the probability density of dispersal distance by wind is different in different plants,at different sites and at different times,and the probability density of seed dispersal distance by wind is higher under logarithmic normal distribution than that of Weibull distribution with higher wind velocity,and the probability density of dispersal distance is higher.The maximum dispersal distance is much larger under the Weibull distribution than the lognormal distribution.Seed wind dispersal distance model is needed to consider the near surface layer aerodynamic parameters and other wind speed distribution models.