Seed dispersal has significantly contributed to horseweed invasion in ecosystems. However, there is a lack of research on long-distance (more than 1 km) and dynamic (hourly) seed movement during an entire seed-shedding season and under different atmospheric conditions. To fill this knowledge gap, the Hybrid Single-Particle Lagrangian Integrated Trajectories (HYSPLIT) model, accounting for meteorological factors and biological dynamics (hourly-order seed emission), was validated using experimental data. The validated model was run for different atmospheric conditions (wind speed and updraft-vertical turbulence) to estimate the longest distance (LD, from the source with more than 1 seed ha⁻¹ deposition) and distribution of seed dispersal during one day (8:00 to 18:00). In a weak wind condition (1–4 m s⁻¹ at 10 m height, standard deviation of vertical wind velocity = 0.5–0.6 m s⁻¹), LD was about 36.5 km, and 4% of seeds were deposited farther than 5 km. In a strong wind condition (5–7 m s⁻¹, 0.8–1 m s⁻¹), LD was 165 km, and 27% were blown farther than 5 km. At the end of the seed-shedding season (44 days), seed dispersal exceeded 186 km; 79% were found within 5 km and 14% were blown farther than 10 km.

种子的扩散对马草入侵生态系统起了重要作用。但是，在整个散种季节和不同大气条件下，对于长距离（超过1公里）和动态（每小时）种子运动的研究缺乏。为了填补这一知识空白，使用实验数据验证了考虑气象因素和生物动力学（按小时顺序排放）的混合单粒子拉格朗日综合轨迹（HYSPLIT）模型。在不同的大气条件（风速和垂直上升湍流）下运行经过验证的模型，以估计最长距离（LD，距具有多于1个ha ^- 1种子的源的LD ）和一天中种子散布的分布（8： 00到18:00）。在弱风条件下（1-4 ms在10 m高度处^-1，垂直风速的标准偏差= 0.5–0.6 ms ^-1），LD约为36.5 km，并且4％的种子沉积的距离超过5 km。在强风条件（5-7毫秒^-1，0.8-1毫秒^-1），LD为165公里，27％的吹制到5公里的更远。在播种季节结束时（44天），种子散布超过186公里；在5公里范围内发现了79％，在10公里范围内被炸毁了14％。