S192 Seasonal and Regional Variability in North Pacific Upper-Ocean Turbulence

Sunday, 10 January 2016
Hall E ( New Orleans Ernest N. Morial Convention Center)
Ryan P. Creedon, The Pennsylvania State University, University Park, PA; and M. F. Cronin and R. G. Najjar

Turbulent diffusion at ocean mixed layer base (MLB) plays a fundamental role in the transport of energy between the upper and abyssal ocean. Recent investigations of North Pacific mooring data at Ocean Climate Stations (OCS) Papa (50.1N,144.9W) and KEO (32.3N,144.6E) suggest seasonal and regional variability in thermal diffusivity (κT). In this investigation, it is hypothesized that these observed differences in κT are directly associated with synoptic variability in net surface heat flux (Q0), surface wind stress (τ), mixed layer depth (h), and density stratification at MLB (∂zσ|-h). To test this hypothesis, daily-averaged time series of κT are regressed against those of Q0, τ, h, and ∂zσ|-h at both Papa and KEO over a six year time period (2007-2013). Seasonality of each time series is removed before regression to capture synoptic variability of each variable. Preliminary results of the regression analysis suggest statistically significant correlations between κT and all forcing parameters at both mooring sites. Corresponding regression coefficients have well-determined orders of magnitude and signs consistent with the hypothesis. As a result, differences in κT between Papa and KEO may be recast in terms of differences in their regression coefficients. In order to continue investigation of these parameters and their effects on mean seasonal differences between the two regions, these results are compared with turbulence predicted by the K-Profile Parameterization ocean turbulence model.
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