Internal Lee Wave Generation from Geostrophic Flow in the Northwestern Pacific Ocean

Among the global mapping of lee wave generation, a missing piece exists in the northwestern Pacific Ocean (NPO), which features complex topographies and energetic circulations. This study applies Bell's theory to estimate and map internal lee waves generated by geostrophic flows in the NPO usin...

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Bibliographic Details
Published in:Journal of Physical Oceanography
Main Authors: Li, Ji, Xu, Zhenhua, Hao, Zhanjiu, You, Jia, Zhang, Peiwen, Yin, Baoshu
Format: Report
Language:English
Published: AMER METEOROLOGICAL SOC 2023
Subjects:
Eddies
Internal waves
Mountain waves
Small scale processes
Topographic effects
Oceanography
SMALL-SCALE TOPOGRAPHY
STRATIFIED FLOW
GLOBAL BATHYMETRY
DISSIPATION
CIRCULATION
ENERGY
TIDE
IMPACT
RIDGE
MORPHOLOGY
Southern Ocean
Pacific
Online Access:http://ir.qdio.ac.cn/handle/337002/183948
http://ir.qdio.ac.cn/handle/337002/183949
https://doi.org/10.1175/JPO-D-23-0035.1
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Summary:Among the global mapping of lee wave generation, a missing piece exists in the northwestern Pacific Ocean (NPO), which features complex topographies and energetic circulations. This study applies Bell's theory to estimate and map internal lee waves generated by geostrophic flows in the NPO using Mercator Ocean reanalysis data and the full topo-graphic spectra obtained from the latest synthetic bathymetry product. Unlike the dominant contributions from abyssal hills in the Southern Ocean, multiple topographies, including ridges, rises, and continental margins, result in an inhomoge-neous lee wave generation with multiple hotspots in the NPO. The generation rate is generally higher in the Philippine basin and lower in the central Pacific seamounts. Over ridges, the rough topography creates a high potential for triggering lee waves. Over rises and continental margins, the stronger currents at the shallow depths are favorable for lee wave gener-ation. In the Kuroshio extension region, the rough topography and strong currents cause the strongest lee wave generation, with an energy flux reaching 100 mW m22. By mean-eddy decomposition, it is found that the lee wave hotspots contrib-uted by mean flow are concentrated in specific regions, while those by geostrophic eddies are widely distributed. Geo-strophic eddies are the primary contributor to lee wave generation, which account for 74.6% of the total energy transferred from geostrophic flow to lee waves. This study also reveals that tides suppress the lee wave generation by 14%, and geo-strophic flow can cause an asymmetric generation of internal tides.

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