Abstract Pollen release by Northern Hemisphere pine forests is well-documented yet little is known about its atmospheric layering. At what altitudes are these atmospheric layers and how do they influence pollen dispersal? To answer this, pollen concentrations were analysed using radiosonde soundings and LiDAR imagery over the Pamlico Sound, a large marine body at 35.4062° N, 76.3259° W between coastal of North Carolina, USA and its barrier islands. Pollen sampled over the sound ranged from 11 to 861 pollen m−3. During daylight, the planetary boundary layer (PBL) height was 1932 m and it was capped by a warm, dry inversion from 2015 to 3072 m. Similarly, PBL height was estimated at 2000 m using a CALIPSO LiDAR image. Mixed-phase clouds could form above the PBL starting at 5650 m where temperatures were less than −13.5 °C and wind speeds exceeded 29.8 m s−1. During cooler night hours, the PBL height dropped to 724 m and its inversion cap also dropped to 1027–1904 m. Strong westerly winds with a low vertical shear drove pollen across water on a cloudless sunny day. Wind speeds below the PBL stayed strong at night while rising relative humidity influenced pollen deposition. Structuring atmospheric layers during pollen dispersal provided more understanding of how long-distance pollen is dispersed at a land–atmosphere interface.

中文翻译：

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松花粉高峰季节的大气分层

摘要 北半球松林释放的花粉已有详细记录，但对其大气分层知之甚少。这些大气层位于什么高度，它们如何影响花粉传播？为了回答这个问题，我们使用无线电探空仪和 LiDAR 图像分析了 Pamlico Sound 上的花粉浓度，Pamlico Sound 是一个大型海洋体，位于美国北卡罗来纳州沿海地区及其屏障岛屿之间，位于北纬 35.4062°，西经 76.3259°。在声音上采样的花粉范围从 11 到 861 花粉 m−3。在白天，行星边界层 (PBL) 高度为 1932 m，并被 2015 年至 3072 m 的温暖干燥逆温覆盖。同样，使用 CALIPSO 激光雷达图像估计 PBL 高度为 2000 米。从 5650 m 开始，温度低于 -13.5 °C 且风速超过 29 的 PBL 上方可能形成混合相云。8 毫秒-1。在较冷的夜间，PBL 高度下降至 724 m，其逆温帽也下降至 1027-1904 m。在晴朗无云的日子里，带有低垂直切变的强西风将花粉吹过水面。低于 PBL 的风速在夜间保持强劲，而相对湿度上升影响花粉沉积。在花粉传播过程中构建大气层可以更好地了解长距离花粉在陆地 - 大气界面上是如何分散的。