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dc.contributor.authorZhang, Zhixiang  Concept link
dc.contributor.authorPratt, Lawrence J.  Concept link
dc.contributor.authorWang, Fan  Concept link
dc.contributor.authorWang, Jianing  Concept link
dc.contributor.authorTan, Shuwen  Concept link
dc.date.accessioned2020-11-20T22:36:49Z
dc.date.available2020-11-20T22:36:49Z
dc.date.issued2020-03-26
dc.identifier.citationZhang, Z., Pratt, L. J., Wang, F., Wang, J., & Tan, S. (2020). Intermediate intraseasonal variability in the western tropical Pacific Ocean: meridional distribution of equatorial Rossby waves influenced by a tilted boundary. Journal of Physical Oceanography, 50(4), 921-933.en_US
dc.identifier.urihttps://hdl.handle.net/1912/26398
dc.descriptionAuthor Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 50(4),(2020): 921-933, doi:10.1175/JPO-D-19-0184.1.en_US
dc.description.abstractIntermediate-depth intraseasonal variability (ISV) at a 20–90-day period, as detected in velocity measurements from seven subsurface moorings in the tropical western Pacific, is interpreted in terms of equatorial Rossby waves. The moorings were deployed between 0° and 7.5°N along 142°E from September 2014 to October 2015. The strongest ISV energy at 1200 m occurs at 4.5°N. Peak energy at 4.5°N is also seen in an eddy-resolving global circulation model. An analysis of the model output identifies the source of the ISV as short equatorial Rossby waves with westward phase speed but southeastward and downward group velocity. Additionally, it is shown that a superposition of first three baroclinic modes is required to represent the ISV energy propagation. Further analysis using a 1.5-layer shallow water model suggests that the first meridional mode Rossby wave accounts for the specific meridional distribution of ISV in the western Pacific. The same model suggests that the tilted coastlines of Irian Jaya and Papua New Guinea, which lie to the south of the moorings, shift the location of the northern peak of meridional velocity oscillation from 3°N to near 4.5°N. The tilt of this boundary with respect to a purely zonal alignment therefore needs to be taken into account to explain this meridional shift of the peak. Calculation of the barotropic conversion rate indicates that the intraseasonal kinetic energy below 1000 m can be transferred into the mean flows, suggesting a possible forcing mechanism for intermediate-depth zonal jets.en_US
dc.description.sponsorshipThis study is supported by the National Natural Science Foundation of China (Grants 91958204 and 41776022), the China Ocean Mineral Resources Research and Development Association Program (DY135-E2-3-02), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant XDA22000000). L. Pratt was supported by the U.S. National Science Foundation Grant OCE-1657870. F. Wang thanks the support from the Scientific and Technological Innovation Project by Qingdao National Laboratory for Marine Science and Technology (Grant 2016ASKJ12), the National Program on Global Change and Air-Sea Interaction (Grant GASI-IPOVAI-01-01), and the National Natural Science Foundation of China (Grants 41730534, 41421005, and U1406401).en_US
dc.publisherAmerican Meteorological Societyen_US
dc.relation.urihttps://doi.org/10.1175/JPO-D-19-0184.1
dc.subjectNorth Pacific Oceanen_US
dc.subjectRossby wavesen_US
dc.subjectModel output statisticsen_US
dc.subjectNumerical analysis/modelingen_US
dc.subjectIntraseasonal variabilityen_US
dc.titleIntermediate intraseasonal variability in the western tropical Pacific Ocean: meridional distribution of equatorial Rossby waves influenced by a tilted boundaryen_US
dc.typeArticleen_US
dc.identifier.doi10.1175/JPO-D-19-0184.1


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