[M-IS12] Geophysical fluid dynamics-Transfield approach to geoscience

[MIS12-P05] Development of a Sea Surface Breaking Wave Observation System Using Industrial Millimeter Wave Radar and an Optical Particle Counter

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

Keywords:whitecap, optical particle counter, millimeter wave rador

During the passage of a typhoon, strong winds cause waves to develop on the ocean surface, generating countless whitecaps. The peaks of each wave are torn off by the strong winds, and a large amount of sea spray is suspended several tens of meters above the sea surface and then falls to the sea surface. Breaking waves produce large and small droplets simultaneously in the atmospheric boundary layer. To elucidate the mechanisms of whitecap breaking waves and the associated microphysical processes in the atmospheric and oceanic boundary layer, conventional observational studies have used visible light CCD cameras to determine sea surface conditions and ultrasonic anemometers and optical particle size counters to measure air currents and particle over the ocean. This research aims to estimate particle fluxes by simultaneous operation of ultrasonic anemometers and an optical particle size counter and is developing a system to measure the spatiotemporal structure of whitecap breaking waves over the ocean using a millimeter wave (30-300 GHz, 1-10 mm wavelength) radar electronic circuit board for automotive parts. This is intended to be applied to rough weather conditions and continuous day/night observations. Millimeter-wave radar has a short wavelength and can be transmitted and received with a small antenna of a few centimeters square, and its hardware development is undergoing a major international revolution. Texas Instruments one-chip integrated circuits contain all the components necessary for imaging, from radio wave transmitter/receiver circuits to analog-to-digital conversion and microcontrollers for signal processing, all on a single chip, and also have a phased array system that can electronically switch the direction of radio wave emission. Based on this system, we have constructed a system that can make measurements at 1-second intervals and are testing it for marine observations.