Publication Date:
2022-05-26
Description:
Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans 124(2), (2019):863-881, doi:10.1029/2018JC014604.
Description:
Pacific Winter Water (PWW) enters the western Arctic Ocean from the Chukchi Sea; however, the physical mechanisms that regulate its circulation within the deep basin are still not clear. Here, we investigate the interannual variability of PWW with a comprehensive data set over a decade. We quantify the thickening and expansion of the PWW layer during 2002–2016, as well as its changing pathway. The total volume of PWW in the Beaufort Gyre (BG) region is estimated to have increased from 3.48 ± 0.04 × 1014 m3 during 2002–2006 to 4.11 ± 0.02 × 1014 m3 during 2011–2016, an increase of 18%. We find that the deepening rate of the lower bound of PWW is almost double that of its upper bound in the northern Canada Basin, a result of lateral flux convergence of PWW (via lateral advection of PWW from the Chukchi Borderland) in addition to the Ekman pumping. In particular, of the 70‐m deepening of PWW at its lower bound observed over 2003–2011 in the northwestern basin, 43% resulted from lateral flux convergence. We also find a redistribution of PWW in recent years toward the Chukchi Borderland associated with the wind‐driven spin‐up and westward shift of the BG. Finally, we hypothesize that a recently observed increase of lower halocline eddies in the BG might be explained by this redistribution, through a compression mechanism over the Chukchi Borderland.
Description:
Three anonymous reviewers provided helpful comments and suggestions, which greatly improved this manuscript. We thank John Marshall (MIT) and Georgy Manucharyan (Caltech) for valuable discussions and inputs. We thank Peigen Lin (WHOI), Qinyu Liu, and Jinping Zhao (OUC) for helpful discussions. The Matlab wind rose toolbox is written by Daniel Pereira. This study is supported by the National Key Basic Research Program of China (Program 973) (2015CB953900; 2018YFA0605901), the Key Project of Chinese Natural Science Foundation (41330960), and the National Natural Science Foundation of China (41706211 and 41776192), the Office of Naval Research (grant N00014‐12‐1‐0112), the NSF Office of Polar Programs (PLR‐1416920, PLR‐1503298, PLR‐1602985, PLR‐1603259, ARC‐1203425, and NSF‐1602926). Wenli Zhong (201606335011) is supported by the China Scholarship Council for his studies in APL. We appreciate Andrey Proshutinsky and Rick Krishfield (WHOI) for providing the Beaufort Gyre Exploration Project data publicly at http://www.whoi.edu/website/beaufortgyre/. The Ice‐Tethered Profiler data were collected and made available by the Ice‐Tethered Profiler Program (Krishfield et al., 2008; Toole et al., 2011) based at the Woods Hole Oceanographic Institution (http://www.whoi.edu/itp). The Monthly Isopycnal/Mixed‐layer Ocean Climatology (MIMOC) data are available at https://www.pmel.noaa.gov/mimoc/. The monthly Arctic Dynamic Ocean Topography data are distributed by CPOM (http://www.cpom.ucl.ac.uk/dynamic_topography/). The IBCAO Bathymetry data are available from NASA (http://www.ngdc.noaa.gov/mgg/bathymetry/arctic/arctic.html). The Data‐Interpolating Variational Analysis method is publicly available at http://modb.oce.ulg.ac.be/mediawiki/index.php/DIVA.
Description:
2019-07-16
Keywords:
Beaufort Gyre
;
Pacific Winter Water
;
PWW pathway
;
lower halocline eddies
;
western Arctic Ocean
Repository Name:
Woods Hole Open Access Server
Type:
Article
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