M₂ baroclinic tide variability modulated by the ocean circulation south of Japan

Abstract

We analyze a concurrent simulation result of the ocean circulation and tidal currents using a data‐assimilative ocean general circulation model covering the Western North Pacific with horizontal resolution of 1/36° to investigate possible interactions between them. Four sites of active M2 internal tide variability in open ocean (hot spots), such as Tokara Strait, Izu Ridge, Luzon Strait, and Ogasawara Ridge, are detected from both the satellite observation and the simulation. Energy cycle analysis of the simulated M2 baroclinic tide indicates two types of the hot spots: dissipation (Tokara Strait and Izu Ridge) and radiation (Luzon Strait and Ogasawara Ridge) dominant sites. Energy conversion from barotropic to baroclinic M2 tides at the hot spots is modulated considerably by the lower‐frequency changes in the density field. Modulation at the two spots (Tokara Strait and Izu Ridge) is affected by the Kuroshio path variation together with the seasonal variation of the shallow thermocline. At the other two sites, influence from changes in the relatively deep stratification through the Kuroshio intrusion into South China Sea (Luzon Strat) and mesoscale eddy activity (Ogasawara Ridge) is dominant in the modulation.

Long‐Range Radiation and Interference Pattern of Multisource M2 Internal Tides in the Philippine Sea

“…Generally, our modeling results for the M 2 barotropic‐to‐baroclinic conversion rates are comparable to the results of previous numerical simulations (Kerry et al, ; Niwa & Hibiya, ). Some differences exist, because of different modeling resolutions and whether to include subtidal circulation, but do not influence the focus on interference patterns in the present study (Kerry et al, ; Varlamov et al, ).…”

Modeling of extreme freshwater outflow from the north-eastern Japanese river basins to western Pacific Ocean

“…To evaluate the impact of extreme river discharges on the coastal ocean environment, the freshwater outflow data were provided as input for integrated hydrological -ocean circulation model JCOPE-T (Varlamov et al, 2015) of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). The used model version had a horizontal resolution of order 3 km, 46 vertical generalizedsigma levels and included simulated tidal processes as well.…”

A new technique for the retrieval of near‐surface vertical current shear from marine X‐band radar images

“…[] and Varlamov et al . [].) We therefore expect our MR currents to be controlled by the large‐scale circulation, which presents a challenge for isolating the wind and wave‐driven components.…”