Arctic bottom water

From Glossary of Meteorology

Arctic Bottom Water

The water mass formed in the Arctic Ocean by a combination of freezing on the arctic shelf and deep winter convection in the Greenland and Norwegian Seas.

Freezing increases the salinity under the ice; the dense water sinks to the ocean floor and leaves the arctic basins to enter the Greenland and Norwegian Seas, where it mixes with water that sinks under the influence of surface cooling. The resulting water mass has a salinity of 34.95 psu and a temperature of -0.8° to -0.9°C. It fills the Arctic Ocean at all depths below 800 m, the sill depth to the Atlantic. It enters the Atlantic in bursts, when the passage of atmospheric depressions lifts the thermocline and allows Arctic Bottom Water to flow over the sill. Overflow events in the Denmark Strait and across the Iceland–Faeroe sill contribute some 5 Sv (5 × 106 m3s-1) to the formation of North Atlantic Deep Water.

Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact [email protected]. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.