Dense water formation in the Laptev Sea flaw lead

• Published in: Journal of Geophysical Research: Oceans Vol. 115; no. C12
• Main Author: Dethleff, Dirk
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.12.2010; American Geophysical Union
• Subjects: Arctic Ocean; Brines; Cryosphere; Deep water; Dense water; Earth sciences; Earth, ocean, space; Eddies; Exact sciences and technology; Expulsion; Geophysics; Halocline; Intermediate water; Intermediate water masses; Marine; Modelling; Oceanography; Physical oceanography; Primitive equations; Rejection; Salt rejection; Surface water; Arctic Ocean; polar regions; Laptev Sea; Arctic region; models; salinity; time scales; salt; geologic sections; Primitive equation; Intermediate water; Deep water; chemically precipitated rocks; buoyancy; evaporites; lead; surface water; sedimentary rocks; brines; gels; separation; Halocline; Polar region; equilibrium; Vortex; injection
• ISSN: 0148-0227; 2169-9275; 2156-2202; 2169-9291
• DOI: 10.1029/2009JC006080

Two primitive equation‐based models are used to estimate the formation of total volumes either of Arctic cold halocline water (CHW), intermediate water (IMW), or deep water (DW) through freeze‐related salt rejection in the Siberian Laptev Sea flaw lead system. Model A assumes that the rejected salt remixes with surface mixed water (SMW) beyond the leads until salinities allow for contribution to the midlayers of either the CHW, the IMW, or the DW. Model B simulates direct salt rejection to the upper layer of the cold halocline, and, after remixing here, further contribution to the midlayers of CHW, IMW, or DW. Averaging both model estimates, Laptev leads contribute either 0.161 Sv of CHW, 0.075 Sv of IMW, or 0.065 Sv of DW, which represents as much as ∼23%, ∼16%, or ∼30% of Arctic‐wide lead derived dense water contribution to the appropriate layer, respectively. Northwestern Laptev leads produce the greatest amount of dense water. These lead sections show very short buoyancy equilibrium timescales (∼6 to ∼13 days), and local dense water production may potentially be amplified by lateral brine injection into the cold halocline through bottom eddies. Central‐southern and southeastern leads generally produce little salt due to low surface water salinities. As definite separation mechanisms and proportion distributions of rejected lead brines into CHW, IWM, and DW are still unidentified in nature, a combination of lead salt rejection and remixing (model A) and direct downward expulsion of brine packages (model B) is assumed to steer Laptev lead dense water production.