Fog Detection Based on Microwave Signal Attenuation

Fog is a meteorological event characterized by visibility reduction to under one kilometer, posing a primary threat to maritime and land vehicle navigation. Visibility and present weather sensors have been introduced to measure fog, however single-point observation cannot determine the horizontal scale of fog. Microwave links have been validated effective in detecting rainfall and estimating rainfall quantitatively by collecting attenuation information from microwaves. Attenuation of microwaves is not limited to precipitation but also occurs in the presence of fog, dust and snow; the higher the frequency, the more pronounced the attenuation effect due to fine particles. This study aims to collect signal data received through a 24 GHz microwave link under various weather conditions and compare those with observed meteorological data to determine the presence or absence of fog and sea fog. This microwave link has a transmitter output of 20 dBm, and the maximum received signal strength appears to be around -100 dBm under clear weather conditions at a distance of 10 km. It was installed over a path length of 11.4 km that crosses the bay between Boseong and Goheung, optimizing it for detecting weather changes. Additionally, A spectrum of the attenuation signal is expected to provide information that can classify clear skies, rain, and fog. This study suggest potential application in monitoring fog with difficult road weather conditions. Furthermore, effective detection with high temporal resolution is expected in observation gap areas, such as urban centers, islands, and mountainous areas. As the UAM (Urban Air Mobility) era arrives, the weather enterprise needs to develop and adapt benchmarks for creating and validating finescale weather guidance for urban aviation. Microwave links would be an answer to this challenge.