CHARACTERIZATION OF SEASONAL VARIATION OF NEAR-INERTIAL ENERGY IN KUROSHIO-OYASHIO MIXED ZONE BASED ON MOORING OBSERVATIONS
Near-inertial waves(NIWs)are widespread in the global ocean,and are a significant energy source for turbulent diapycnal mixing in the deep ocean to maintain ocean stratification.Based on multi-year deep-sea mooring data collected in the Kuroshio-Oyashio mixed zone,we focused on the seasonal variations and the dominant factors in determining near-inertial kinematic energy in this region,and the characteristics of wave frequency,wavenumber spectrum,and vertical distribution of near-inertial motions in the upper and deep ocean.Results revealed the presence of abundant near-inertial kinetic energy in this region.Both the upper and deep ocean layers exhibit notable seasonal variation,and are characterized by pronounced intensification in winter and weakening in summer.Specifically,in winter months,near-inertial energy in the upper layer can contribute to 41％of the total annual energy.Moreover,the near-inertial energy in the deep-layer ocean is equally significant,being comparable to the tidal signals.The slab model suggests that these seasonal cycles of near-inertial energy are primarily driven by external wind forcing,with additional influence from the northward shift of the Kuroshio extension axis.
NETL
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万方数据
