Ocean Observing and Climate
Polar and Subpolar Oceans
Polar and Subpolar Oceans
The physical processes in the high latitude oceans are critically important to both regional and global climate. The export of cold, fresh water from the Arctic and Southern Ocean are key to the density-driven ocean circulation that re-distributes heat around the world. The subpolar North Atlantic is a region of intense exchange of heat, freshwater and momentum with the atmosphere, and links the Arctic to the global ocean. Our research into mixing processes, circulation, freshwater transports and long-term variability of the subpolar and polar oceans is driving forward our knowledge of these regions.
Climate Group Investigators: S. Bacon, N.P. Holliday, T. Tsubouchi
PhD students: A. Kaczmarska and Y. Mao
Key Research Activities
* North Atlantic Circulation and Transports
The focus of this programme is the analysis of trans-ocean basin hydrographic sections to calculate fluxes of volume, heat, freshwater and carbon. The two major sections are Canada-Greenland-Scotland (the Arctic Gateway cruise, completed in 2008) and the 26N section (to complement the RAPID array , completed in early 2010).
This programme forms work package 1.2 of the NERC-funded Oceans2025 and builds on work completed under the NERC-RAPID programme
Bacon and Saunders, in press, The Deep Western Boundary Current at Cape Farewell: Results from a moored current meter array. JPO
Holliday et al (2009) Circulation and transport in the western boundary currents at Cape Farewell, Greenland. JPO
Holliday et al (2007) The retroflection of part of the East Greenland Current at Cape Farewell. GRL
Lauderdale et al (2008) Intensified turbulent mixing in the boundary current system of southern Greenland. GRL
* Arctic Synoptic Basin-wide Observations
This NERC-funded consortium programme is using models and observations to provide new quantitative estimates of the storage and transport of fresh water in the Arctic both for the present, recent past and next century.
The ASBO project pages give further information.
* Long-term North Atlantic Variability
Using repeat hydrographic sections in subpolar North Atlantic we are investigating the long-term changes in temperature, salinity and circulation. The time-scales we are interested in range from seasonal to multi-decadal, and we are seeking to describe the variability, understand the interaction of variability on different timescales, and to identify the mechanisms that influence physical conditions.
One of the main resources for our analysis is the Extended Ellett Line maintained under the Oceans2025 sustained observations programme.
Hughes et al (2009) Comparison of in situ time-series of temperature with gridded sea surface temperature datasets in the North Atlantic. ICES JMS
Holliday et al (2008) Reversal of the 1960s to 1990s freshening trend in the northeast North Atlantic and Nordic Seas. GRL
Yashayaev et al (2007) Transformation of the Labrador Sea water in the subpolar North Atlantic. GRL
* Antarctic Deep Water Rates of Export (ANDREX)
The ANDREX project seeks to assess the role of the Weddell gyre in driving the southern closure of the meridional overturning circulation, in ventilating the deep global ocean, and in sequestering carbon and nutrients in the global ocean abyss. To do this, the ANDREX team and a group of U.S. collaborators set out to obtain measurements of hydrography, velocity and a range of ventilation tracers and biogeochemical substances along the Weddell gyre's outer rim.
The ANDREX project pages give further information
Community Activities
We are members of the following working groups and committees:
NOCS Arctic Focus Group (Bacon - Leader, Holliday)
ICES Strategic Initiative on Climate Change (Holliday)
ICES Working Group on Oceanic Hydrography (Holliday)
