This paper presents an empirical study of dynamic factors affecting link quality in Low Earth Orbit (LEO) satellite communications, using Starlink as a case study. Over 56 days, 112 high-quality meteorological measurements in mostly 1-min intervals, co-located with a user terminal, were collected, alongside frequent network performance data. Cloud characteristics were estimated using professional weather instruments such as a ceilometer, microwave radiometer, and vision-language model on sky images. Our results show that general cloud presence does not significantly impact throughput or latency. The impact of cloud coverage rather depends on the presence of liquid water in the atmosphere, quantified by liquid water path (LWP), which correlates with notable download throughput reductions (up to 60 MBit/s), especially during rain. Upload and latency were largely unaffected. Analysis of the evolving satellite network revealed that newer satellite hardware and infrastructural upgrades also contributed to performance increases during the experiment period. These findings highlight atmospheric liquid water as the key weather-related factor affecting link quality and underscore the influence of network changes over time.

翻译：本文以Starlink为案例，对影响低地球轨道卫星通信链路质量的动态因素进行了实证研究。在56天期间，我们在用户终端旁收集了112组高质量气象测量数据（多数以1分钟为间隔），并同步获取了频繁的网络性能数据。云层特征通过专业气象仪器（包括云高仪、微波辐射计）以及对天空图像应用视觉-语言模型进行估算。研究结果表明，普通云层存在对吞吐量或延迟无显著影响。云层覆盖的影响实际上取决于大气中液态水的存在，以液态水路径量化；该参数与下载吞吐量显著下降（最高达60 MBit/s）相关，尤其在降雨期间。上传速度和延迟基本不受影响。对演进卫星网络的分析表明，实验期间更新的卫星硬件与基础设施升级同样促进了性能提升。这些发现明确了大气液态水是影响链路质量的关键气象因素，并凸显了网络随时间演进的影响。