The Estimate Of Vertical Eddy Diffusivity Of Upper Layer In The Canada Basin

The vertical eddy diffusivityκand eddy viscosityνare important to express the verticalsubstance transferring in dynamical studies and various numerical models. In Arctic Ocean, as anice-covered ocean, the turbulent parameters are quite different from the other oceans, which is stillkept less understanding as lack of observation. Canada Basin, as the largest Basin in the ArcticOcean, participates the Ocean-Atmosphere-Ice interaction and is especially sensitive to theclimate. Research about the vertical eddy diffusivityνand eddy viscosityκ, as a result, has apractical and scientific value.Using the temperature, salinity and current profiling datas in Canada Basin obtained from theChinese Arctic Research Expedition cruise of 2003 summer, we calculate the vertical distributionsofνandκ. Also, we compare and analyze theνandκof different sea areas. The methodused here is proposed by Pacanowski & Philander, which determined the vertical eddydiffusivities and viscosity by the Richardson Number.The results show that the distributions ofνandκare not consistent in verticaldistribution: the values ofκandνare large in the water lower than 24m; while, in the waterdeeper than 14m,κandνare small and almost consistent;κbecome large again in thethermocline, as a result of double-diffusive process.The distribution ofκandνof different sea areas are not consistent. According to the iceposts, differences are obvious in the water lower than 24m. In the water between surface andthermocline, the vertical differences ofνandκare small. However, areas' differences ofbuoyancy frequency N and shear S result in different vertical distributions ofνandκindifferent sea areas.The well-formed staircase is suggestive of double-diffusive processes observed in thethermocline in Canadian basin. From the value of density ratio R_ρ, the thermocline in thesouthwestern Canadian basin is stabler than that in the central Canadian basin. The average heat flux of the double-diffusive interfaces in the southwestern Canadian basin are: F_H1=1.1 W/m²,F_H2=0.8W/m², while, in the central Canadian basin: F_H1=0.9 W/m², F_H2=1.3W/m².