Development of Efficient and Autonomous Microstructure Measurement System Using Fast-response Thermistors Attached to CTD, Glider and Deep-profiling float, to Elucidate Turbulence Distribution

Keunjong Lee1, Ichiro Yasuda2, Yasutaka Goto3, Maki Nagasawa4, Shuo Zhai4, Daigo Yanagimoto2, Shinzou Fujio2, Mamoru Tanaka4, Shinya Kouketsu5, Toshiya Nakano6, Daisuke Sasano6 and Takahiro Tanaka7, (1)Korea Institute of Ocean Science and Technology, Busan, South Korea, (2)Atmosphere and Ocean Research Institute, University of Tokyo, Tokyo, Japan, (3)Japan Meteorological Agency, Japan, (4)Atmosphere and Ocean Research Institute, University of Tokyo, Japan, (5)JAMSTEC, Yokosuka, Japan, (6)Global Environment and Marine Department, Japan Meteorological Agency, Tokyo, Japan, (7)Tohoku National Fisheries Research Institute, Japan Fisheries Research and Education Agency, Shiogama, Japan
Abstract:
A new efficient microstructure measurement with fast-response thermistors attached to CTD, underwater glider and deep float were elaborated. The CTD-attached thermistor measurements were confirmed to be valid in the weak turbulent energy dissipation down to 10-11 W/kg by comparing with the one by free-fall instrument with the best accuracy, and revealed cross-Pacific top-bottom turbulence distribution. Vertical distribution of turbulent energy dissipations found to be proportional with local squared buoyancy frequency N2 (representing density vertical gradient) and local internal tide energy generation and dissipation, indicating that energy dissipation of tide-induced turbulence occurs in the main thermocline. Thermistor measurements attached to gliders and deep floats were also confirmed to be useful to measure weak turbulence area as in the deep water as well as the water where double-diffusive convections work. These contribute to revising models of tide-induced three-dimensional distribution used in ocean/climate models, which will contribute to reproducing ocean meridional overturning circulation and oceanic heat/material circulation.