HR: 13:40h
AN: OS43C-01    [Abstracts]
TI: Determination Of The Diapycnal Diffusion Rates In The Upper Thermocline In The North Atlantic Ocean Using Sulfur Hexafluoride
AU: * Kim, D
EM: nandama@postech.ac.kr
AF: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, 790-784 Korea, Republic of
AU: Lee, K
EM: ktl@postech.ac.kr
AF: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, 790-784 Korea, Republic of
AU: Choi, S
EM: skills@postech.ac.kr
AF: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, 790-784 Korea, Republic of
AU: Kang, H
EM: Heesook.Kang@noaa.gov
AF: Rosenstiel School of Marine and Atmospheric Science/MPO, University of Miami, Miami, FL 33149 United States
AU: Wanninkhof, R
EM: Rik.Wanninkfof@noaa.gov
AF: Atlantic Oceanographic and Meteorological Laboratory/NOAA, NOAA/Miami, Miami, FL 33149 United States
AB: The apparent diapycnal diffusivity below the wind-driven surface mixed layer of the ocean was determined in a cyclonic (warm core) eddy in the eastern North Atlantic using sulfur hexafluoride (SF6) tracer data collected during the Gas Ex-98 cruise in June 1998. In this tracer experiment, the downward penetration of SF6 was measured for 3 weeks following the deliberate injection of SF6 at the base of the surface mixed layer. The resulting data were used to constrain the Price, Weller, and Pinkel (1986) mixed layer model to estimate the diapycnal diffusivity. The model includes the lateral diffusion component so that it can more accurately represent the time evolution of the [SF6] along the isopycnal surface. The lateral spreading affects the estimation of the diapycnal diffusivity. For the upper thermocline immediately below the surface mixed layer, we estimated the diapycnal diffusivity for the 3-week period as 0.4 $\pm$ 0.2 cm$^{2}$ s$^{-1}$ at a buoyancy frequency of 8.2 cph. This result is about two times lower than the estimate based on an analytical solutions using the second moment of the profiles over time.
DE: 4568 Turbulence, diffusion, and mixing processes
DE: 4572 Upper ocean processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting