Scottish Association for Marine Science

About: Scottish Association for Marine Science is a facility organization based out in Oban, United Kingdom. It is known for research contribution in the topics: Sea ice & Benthic zone. The organization has 524 authors who have published 1765 publications receiving 70783 citations. The organization is also known as: SAMS & Scottish Marine Station for Scientific Research.

The Kongsfjorden Transect:: seasonal and inter-annual variability in hydrography

Abstract: The Kongsfjorden conductivity, temperature and depth (CTD) Transect has been monitored annually since 1994. It covers the full length of the fjord and the shelf, and the upper part of the shelf slope outside Kongsfjorden. In addition to CTD profiles, data from vessel-mounted Acoustic Doppler Current Profiler (ADCP) and moorings have been collected. Previous studies noted that Atlantic Water (AW) from the West Spitsbergen Current was observed in the fjord every summer, but to a varying extent. The prolonged monitoring provided by the Kongsfjorden Transect data set examined here reveals continuous variations in AW content and vertical distribution in the fjord, both on seasonal and inter-annual timescales. Our focus in this paper is on this variable content of AW in Kongsfjorden, the forcing mechanisms that may govern the inflow of this water mass, and its distribution in the fjord. We classify three winter types linked to three characteristic scenarios for winter formation of water masses. During the historically typical winters of type “Winter Deep”, deep convection, often combined with sea ice formation, produces dense winter water that prevents AW from entering Kongsfjorden. Summer inflow of AW starts when density differences between fjord and shelf water allows for it, and occurs at some intermediate depth. During winters of type “Winter Intermediate”, AW advects into the fjord along the bottom via Kongsfjordrenna. Winter convection in Kongsfjorden will then be limited to intermediate depth, usually producing very cold intermediate water. Deep AW inflow continues during the following summer. A winter of type “Winter Open” seems to develop when open water convection produces very dense shelf water, and AW winter advection into Kongsfjorden occurs at the surface. Summer AW inflow is rather shallow after such winters. We find that variations between Winter Deep and Winter Intermediate winters are due to inherent natural variability. However, the Winter Open winters seem to be a consequence of the general trend of atmospheric and oceanic warming, and, more specifically, of the decreasing sea ice cover in the Arctic region. The Winter Open winters have all occurred after an unusual flooding of AW onto the West Spitsbergen shelf in February 2006.

Mixing and advection of a cold water cascade over the Wyville Thomson Ridge

Abstract: The Wyville Thomson Ridge forms part of the barrier to the meridional circulation across which cold Nordic Sea and Arctic water must traverse to reach the Atlantic Ocean. Overflow rates across the ridge are variable (but can be dramatic at times), and may provide a subtle indicator of significant change in the circulation in response to climate change. In spring 2003, a series of CTD sections were conducted during a large overflow event in which Norwegian Sea Deep Water (NSDW) cascaded down the southern side of the ridge into the Rockall Trough at a rate of between 1 and 2 Sv. The NSDW was partially mixed with overlying North Atlantic Water (NAW), and comprised about 1/3rd of the cascading water. The components of NAW and NSDW in the overflow were sufficiently large that there must have been a significant divergence of the inflow through the Faroe-Shetland Channel, and of the outflow through the Faroe Bank Channel. As the plume descended, its temperature near the sea bed warmed by over 3 °C in about a day. Although the slope was quite steep (0.03), the mean speed of the current (typically 0.36 m s −1 ) was too slow for significant entrainment of NAW to occur (the bulk Richardson number was of order 5). However, very large overturns (up to 50 m) were evident in some CTD profiles, and it is demonstrated from Thorpe scale estimates that the warming of the bottom waters was due to mixing within the plume. It is likely that some of the NSDW had mixed with NAW before it crossed the ridge. The overflow was trapped in a gully, which caused it to descend to great depth (1700 m) at a faster rate, and with less modification due to entrainment, than other overflows in the North Atlantic. The water that flowed into the northern part of the Rockall Trough had a temperature profile that ranged from about 3 to 8 °C. Water with a temperature of >6 °C probably escaped into the Iceland Basin, between the banks that line the north-western part of the Trough. Colder water (

Characterization of Arctic Sea Ice Thickness Using High-Resolution Spaceborne Polarimetric SAR Data

Abstract: In this paper, we have investigated the relationship between the depolarization effects and the wintertime sea ice thickness in the landfast ice region where smooth thick first-year ice (FYI) and deformed old ice coexisted by using C- and X-band spaceborne polarimetric synthetic aperture radar (SAR) data (RADARSAT-2 and TerraSAR-X). We have found a strong correlation between the in situ sea ice thickness and the SAR-derived depolarization factors (copolarized correlation and cross-polarized ratio). The observed relationships have demonstrated not only a categorical difference between FYI and multiyear ice (MYI) but also a one-to-one continuity in the scatter plots, rather than being clustered. It clearly shows that the observed correlations are not merely from the categorical difference in scattering mechanism between FYI and MYI and that there might exist a one-to-one relationship between thickness and depolarization factors at least in our deformed ice case. This suggests that depolarization factors could be effective SAR parameters in the estimation of wintertime sea ice thickness. Numerical model simulations explained some portions of the correlation by employing multiple scattering on the sea ice surface and volume scattering within the low-density subsurface layer.

Carrying and assimilative capacities: the ACExR-LESV model for sea-loch aquaculture

Abstract: This paper introduces a DPSIR framework for the estimation of the aquacultural carrying and waste-assimilating capacities of fjordic water bodies. The ACExR-LESV physical–biological model, intended as a water quality management support tool by simulating pressure–impact relationships, is described in outline. Results of testing in a typical Scottish fjord are reported, and the estimation of a loch's capacity to assimilate waste from finfish farming is exemplified.