[M-IS24] Geophysical fluid dynamics-Transfield approach to geoscience

[MIS24-P02] Development of sea surface wave breaking observation system using industrial millimeter radar and optical particle size counter

*Hidenori AIKI¹, Fumiyoshi Kondo², Haruya Minda¹ (1.Nagoya University, 2.Japan Coast Guard Academy)

When a typhoon passes over the sea surface, strong winds cause waves to develop and countless whitecap waves are generated. Large and small droplets are simultaneously generated in the atmospheric boundary layer by the whitecap breaking waves. Large droplets play an important role in the transport of momentum, heat, and CO2 between the atmosphere and the ocean due to their large mass. The small droplets become oceanic aerosols that form cloud condensation nuclei a few kilometers above the surface and contribute to the radiation budget of the atmosphere. Conventional observation of whitecap breaking waves using a CCD camera was affected by fog and sunlight and was not suitable for continuous observation during stormy weather or day and night. In this study, we develop a system to measure the spatio-temporal structure of whitecap breaking waves at sea using millimeter-wave radar electronic circuit boards for automobile parts. Since the resolution of millimeter-wave radar is a few millimeters to a few centimeters, it is ideal for capturing the dynamics of individual whitecap waves and sea spray layer. Since the temporal variation of the particle size distribution is also important information, the optical particle size counter for marine observation developed by the authors is used in combination with the radar.