Asymmetrically Stratified Beaufort Gyre: Mean State and Response to Decadal Forcing

Journal Article · Thu Dec 29 00:00:00 EST 2022 · Geophysical Research Letters

DOI:https://doi.org/10.1029/2022GL100457· OSTI ID:1907131

Zhang, Jiaxu ^[1]; Cheng, Wei ^[1]; Steele, Michael ^[2]; Weijer, Wilbert ^[3]

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1. Cooperative Institute for Climate, Ocean, and Ecosystem Studies University of Washington Seattle WA USA, NOAA Pacific Marine Environmental Laboratory Seattle WA USA
2. Applied Physics Laboratory University of Washington Seattle WA USA
3. Computational Physics and Methods Los Alamos National Laboratory Los Alamos NM USA

Abstract

Recent progress in understanding Beaufort Gyre (BG) dynamics reveals an important role of ice‐ocean stress in stabilizing BG freshwater content (FWC) over seasonal to interannual timescales. But how the BG's stratification and FWC respond to surface forcing over decadal timescales has not been fully explored. Using a global ocean‐sea ice model, we partition the BG into upper, middle (halocline), and lower (thermocline) layers and perform a volume budget analysis over 1948–2017. We find that the BG's asymmetric geometry (with steep and tight isohalines over continental slopes relative to the deep basin) is key in determining the mean volume transport balance. We further find that a net Ekman suction during 1983–1995 causes the upper and middle layers to deflate isopycnally, while an enhanced Ekman pumping during 1996–2017 causes these layers to inflate both isopycnally and diapycnally, the latter via anomalous flux from the upper to the middle layer.

• Sponsoring Organization: USDOE
• OSTI ID: 1907131
• Alternate ID(s): OSTI ID: 1923401
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 1 Vol. 50; ISSN 0094-8276
• Publisher: American Geophysical Union (AGU)
• Country of Publication: United States
• Language: English