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Papers by Kenneth Drinkwater

Journal of Marine Systems, 2014

This paper examines the multidecadal variability in the northern North Atlantic and the Arctic. O... more This paper examines the multidecadal variability in the northern North Atlantic and the Arctic. Observations, modeling and paleo data provide evidence of a strong link between the atmospheric and physical oceanographic variability in these northern regions with Atlantic sea surface temperatures farther south as expressed by the Atlantic Multidecadal Oscillation (AMO). Air and sea temperatures over the past 100-150 years reveal cool periods in the late 1800s to early 1900s and in the 1970s to 1980s with warm periods during the 1920s to 1960s and from the 1990s through to the present, similar to the variability in the AMO index where a positive (negative) AMO index represents warm (cold) periods. Sea-ice extent in the north has also varied at multidecadal scales with the ice retreating during the warm periods and expanding during the cold periods. The presence of multidecadal variability is also suggested from marine sediment paleo data as well as ice-core oxygen isotope data. Observations of biological impacts of the multidecadal variability in the northern regions include a general increase in plankton and fish productivity, as well as expansion of the species distributions northward, in conjunction with the AMO warm periods and the opposite during AMO cold periods. In addition, a review of the mechanisms responsible for the AMO and a brief discussion of the linkages between the multidecadal variability in the northern and southern hemispheres, including between the Arctic and Antarctic, are presented.

Journal of Northwest Atlantic Fishery Science, 1996

A review of atmospheric and oceanographic conditions in the northwest Atlantic during the 1980s a... more A review of atmospheric and oceanographic conditions in the northwest Atlantic during the 1980s and early 1990s is presented based upon standard station data and climate indices. Air temperatures over Baffin Bay and the Labrador Sea were generally cold in contrast to warm conditions along the Middle Atlantic Bight. These are linked to the largescale atmospheric circulation patterns which produced strong northwest and southwest winds, respectively, over the two regions. The cold air masses and strong northwest winds in the northern regions resulted in more extensive sea ice coverage than normal. Extremely cold ocean temperatures were observed in the Grand Banks region and contrast with the warm temperatures in the deep waters in shelf regions further south. Ocean climate variability has been found to be influenced not only by local atmospheric forcing but also by the advection of water from upstream. Offshore exchange between the slope and shelf waters is a believed to be the primary mechanism for climate changes from the Laurentian Channel to the Middle Atlantic Bight.

… the Fisheries Board of …, 1976

Page 1. Coastal Circulation and Physical Oceanography of the Scotian Shelf and the Gulf of Mainel... more Page 1. Coastal Circulation and Physical Oceanography of the Scotian Shelf and the Gulf of Mainel WH Surclrpre Jn. ... dence to suggest that the river's effect on tem-perature is transmitted by the existing coastal circulation southward from the Gulf of St. ...

The Journal of Parapsychology, Mar 22, 2012

The Journal of Parapsychology, Sep 22, 2013

ABSTRACT First Page of the Article

Journal of Marine Systems, 2014

The Jan Mayen Ridge, with bottom depths of 1000 m and less, runs southwards from Jan Mayen and se... more The Jan Mayen Ridge, with bottom depths of 1000 m and less, runs southwards from Jan Mayen and separates the warmer and saltier Atlantic Water in the Norwegian Sea from the colder and fresher Arctic water in the Iceland Sea. During the International Polar Year (IPY, 2007(IPY, -2008, three current meter moorings were deployed with the purpose to investigate water mass exchanges between the Norwegian and Iceland seas over the Ridge and their forcing mechanisms. These are the first in-situ current measurements for this region. The results showed relatively weak currents on the Ridge that frequently shifted direction except near-bottom and at the western slope of the Ridge. All current measurements showed low eddy activity and tidal velocities (less than 0.05 ms −1 ). Wind-forced near-inertial motion generated from transient atmospheric low pressure systems were observed in the mixed layer being strongest during autumn and winter when ocean velocities reached 0.7 ms −1 . Near surface currents on the Ridge are influenced by local winds on a time scale of 6 days and longer, but during the two-year deployment no pronounced seasonal variation was observed, mainly due to a lack of seasonality in the local winds. In a 2000 m deep channel that cuts the Ridge, there was pronounced seasonal variation in the currents at all depths below 40 m with stronger flow toward the Iceland Sea during winter compared to summer. The variability of the deep current was found to be influenced by the large-scale wind stress curl. There was a weak net flow with averaged velocities of~0.01 ms −1 over the Ridge that was directed westward in the upper layer, signifying a small net transport of modified Atlantic Water into the Iceland Sea.

Progress in Oceanography, 2013

Journal of Marine Systems, 2013

Fisheries Oceanography, 2007

An unusually high abundance of long-finned squid (Loligo pealeii) was observed around southern Ne... more An unusually high abundance of long-finned squid (Loligo pealeii) was observed around southern Newfoundland in August-September 2000. The prevalence of maturing females and mature males, along

Can J Fisheries Aquat Sci, 1998

ABSTRACT We compared habitat associations of southern Gulf of St. Lawrence Atlantic cod (Gadus mo... more ABSTRACT We compared habitat associations of southern Gulf of St. Lawrence Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) between the summer feeding season on the Magdalen Shallows and the overwintering period in the Cabot Strait. Data were from bottom trawl surveys conducted in September 1993, 1994, and 1995 and January 1994, 1995, and 1996. Both species occupied much deeper, warmer water in winter than in summer. The effect of cod age on temperature distribution reversed between the two seasons, with younger cod occupying warmer water than older cod in summer and colder water in winter. Selection of both depth and temperature by cod tended to be more significant in September than in January. The reduced statistical significance of habitat selection by cod in winter was associated with a more aggregated distribution in this season. The contrast between seasons in habitat associations was particularly strong for plaice. The median habitats occupied by plaice were 58-67 m and -0.1 to 0.3°C in September and 374-426 m and 5.2-5.4°C in January. Habitat selection by plaice was significant in both seasons, but significance tended to be greater in January. Degree of aggregation in plaice distribution was similar between the two seasons. Female plaice occupied significantly warmer water than males in September but not in January. The ecological and practical implications of this striking seasonal variation in habitat associations are discussed.

Biological Oceanography, 1988

Agu Fall Meeting Abstracts, Dec 1, 2006

A large amount of freshwater, mostly of riverine origin, flows along the southern side of Hudson ... more A large amount of freshwater, mostly of riverine origin, flows along the southern side of Hudson Strait and into the Labrador Sea. Here it combines with the fresh outflow from Davis Strait and merges into the Labrador Current, whose fresh surface layers flow close to the deep convection region of the Labrador Sea. Thus, variations in the outflow from Hudson Strait have the potential to impact dense water formation in the Labrador Sea. A comparison of year-long mooring array data from 1986-1987 and from 2004-2005 shows a significant decrease in the freshwater outflow from Hudson Strait (accompanied by an increase in the heat transport). Such a change is in agreement with the observed decreasing trend in river input into the Hudson Bay System and with the decreasing trend in sea-ice cover of the region over the last 20 years. The fact that the changes in the mooring data do not simply reflect interannual variations is supported by the analysis of hydrographic data from the upstream Hudson Bay System.

Recent changes in climate conditions in several regions of the globe raise concerns about ecosyst... more Recent changes in climate conditions in several regions of the globe raise concerns about ecosystem resilience and sustainability of ecosystem services. We examine oceanographic responses to these climate changes in four high latitude regions of the Northern Hemisphere, two in the Pacific (Bering Sea and Gulf of Alaska) and two in the Atlantic (Georges Bank/Gulf of Maine and the Barents/Norwegian Seas). Air temperature, heat fluxes and wind forcing over the four regions are examined. The effects of these on the oceanography of the regions are then determined, compared and contrasted, including changes in ocean temperatures, salinities, stratification, and circulation patterns. In addition, changes in seasonal sea ice cover are compared between the two regions where it occurs (Bering and Barents seas). Changes in temperature and salinity are examined as a function of latitude and compared to expected changes (increasing temperature and decreasing salinities in the north). The importa...

Deep Sea Res Pt Ii Top St Oce, 2007

Canadian Journal of Fisheries and Aquatic Sciences, 2001

Physical, chemical, and biological data collected on the Labrador Shelf in September 1985 are use... more Physical, chemical, and biological data collected on the Labrador Shelf in September 1985 are used to examine a hypothesis that the nutrient influx from Hudson Strait increases primary production on the northern shelf and this supports a "conveyor belt" food chain as the community is transported southward by the mean circulation. This hypothesized influx of production was proposed to account for the higher fish abundance on the southern Labrador Shelf. If true, the hypothesis suggests that the relative importance of higher trophic levels generally should increase southeastward along the shelf. Our results confirm that high nutrient levels occur on the northern Labrador Shelf in summer because of continuous advection of nutrients from Hudson Strait and this enhances local plankton production. However, nutrient, chlorophyll a, plankton species, and biomass spectra distributions generally do not support the idea that a developing food chain is advected progressively southward along the shelf. The large fish population on the southern Labrador Shelf appears to have been more dependent on production supported by local upwelling around Hamilton Bank than on food advected from the north.

Journal of Marine Systems, 2014

This paper examines the multidecadal variability in the northern North Atlantic and the Arctic. O... more This paper examines the multidecadal variability in the northern North Atlantic and the Arctic. Observations, modeling and paleo data provide evidence of a strong link between the atmospheric and physical oceanographic variability in these northern regions with Atlantic sea surface temperatures farther south as expressed by the Atlantic Multidecadal Oscillation (AMO). Air and sea temperatures over the past 100-150 years reveal cool periods in the late 1800s to early 1900s and in the 1970s to 1980s with warm periods during the 1920s to 1960s and from the 1990s through to the present, similar to the variability in the AMO index where a positive (negative) AMO index represents warm (cold) periods. Sea-ice extent in the north has also varied at multidecadal scales with the ice retreating during the warm periods and expanding during the cold periods. The presence of multidecadal variability is also suggested from marine sediment paleo data as well as ice-core oxygen isotope data. Observations of biological impacts of the multidecadal variability in the northern regions include a general increase in plankton and fish productivity, as well as expansion of the species distributions northward, in conjunction with the AMO warm periods and the opposite during AMO cold periods. In addition, a review of the mechanisms responsible for the AMO and a brief discussion of the linkages between the multidecadal variability in the northern and southern hemispheres, including between the Arctic and Antarctic, are presented.

Journal of Northwest Atlantic Fishery Science, 1996

A review of atmospheric and oceanographic conditions in the northwest Atlantic during the 1980s a... more A review of atmospheric and oceanographic conditions in the northwest Atlantic during the 1980s and early 1990s is presented based upon standard station data and climate indices. Air temperatures over Baffin Bay and the Labrador Sea were generally cold in contrast to warm conditions along the Middle Atlantic Bight. These are linked to the largescale atmospheric circulation patterns which produced strong northwest and southwest winds, respectively, over the two regions. The cold air masses and strong northwest winds in the northern regions resulted in more extensive sea ice coverage than normal. Extremely cold ocean temperatures were observed in the Grand Banks region and contrast with the warm temperatures in the deep waters in shelf regions further south. Ocean climate variability has been found to be influenced not only by local atmospheric forcing but also by the advection of water from upstream. Offshore exchange between the slope and shelf waters is a believed to be the primary mechanism for climate changes from the Laurentian Channel to the Middle Atlantic Bight.

… the Fisheries Board of …, 1976

Page 1. Coastal Circulation and Physical Oceanography of the Scotian Shelf and the Gulf of Mainel... more Page 1. Coastal Circulation and Physical Oceanography of the Scotian Shelf and the Gulf of Mainel WH Surclrpre Jn. ... dence to suggest that the river's effect on tem-perature is transmitted by the existing coastal circulation southward from the Gulf of St. ...

The Journal of Parapsychology, Mar 22, 2012

The Journal of Parapsychology, Sep 22, 2013

ABSTRACT First Page of the Article

Journal of Marine Systems, 2014

The Jan Mayen Ridge, with bottom depths of 1000 m and less, runs southwards from Jan Mayen and se... more The Jan Mayen Ridge, with bottom depths of 1000 m and less, runs southwards from Jan Mayen and separates the warmer and saltier Atlantic Water in the Norwegian Sea from the colder and fresher Arctic water in the Iceland Sea. During the International Polar Year (IPY, 2007(IPY, -2008, three current meter moorings were deployed with the purpose to investigate water mass exchanges between the Norwegian and Iceland seas over the Ridge and their forcing mechanisms. These are the first in-situ current measurements for this region. The results showed relatively weak currents on the Ridge that frequently shifted direction except near-bottom and at the western slope of the Ridge. All current measurements showed low eddy activity and tidal velocities (less than 0.05 ms −1 ). Wind-forced near-inertial motion generated from transient atmospheric low pressure systems were observed in the mixed layer being strongest during autumn and winter when ocean velocities reached 0.7 ms −1 . Near surface currents on the Ridge are influenced by local winds on a time scale of 6 days and longer, but during the two-year deployment no pronounced seasonal variation was observed, mainly due to a lack of seasonality in the local winds. In a 2000 m deep channel that cuts the Ridge, there was pronounced seasonal variation in the currents at all depths below 40 m with stronger flow toward the Iceland Sea during winter compared to summer. The variability of the deep current was found to be influenced by the large-scale wind stress curl. There was a weak net flow with averaged velocities of~0.01 ms −1 over the Ridge that was directed westward in the upper layer, signifying a small net transport of modified Atlantic Water into the Iceland Sea.

Progress in Oceanography, 2013

Journal of Marine Systems, 2013

Fisheries Oceanography, 2007

An unusually high abundance of long-finned squid (Loligo pealeii) was observed around southern Ne... more An unusually high abundance of long-finned squid (Loligo pealeii) was observed around southern Newfoundland in August-September 2000. The prevalence of maturing females and mature males, along

Can J Fisheries Aquat Sci, 1998

ABSTRACT We compared habitat associations of southern Gulf of St. Lawrence Atlantic cod (Gadus mo... more ABSTRACT We compared habitat associations of southern Gulf of St. Lawrence Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) between the summer feeding season on the Magdalen Shallows and the overwintering period in the Cabot Strait. Data were from bottom trawl surveys conducted in September 1993, 1994, and 1995 and January 1994, 1995, and 1996. Both species occupied much deeper, warmer water in winter than in summer. The effect of cod age on temperature distribution reversed between the two seasons, with younger cod occupying warmer water than older cod in summer and colder water in winter. Selection of both depth and temperature by cod tended to be more significant in September than in January. The reduced statistical significance of habitat selection by cod in winter was associated with a more aggregated distribution in this season. The contrast between seasons in habitat associations was particularly strong for plaice. The median habitats occupied by plaice were 58-67 m and -0.1 to 0.3°C in September and 374-426 m and 5.2-5.4°C in January. Habitat selection by plaice was significant in both seasons, but significance tended to be greater in January. Degree of aggregation in plaice distribution was similar between the two seasons. Female plaice occupied significantly warmer water than males in September but not in January. The ecological and practical implications of this striking seasonal variation in habitat associations are discussed.

Biological Oceanography, 1988

Agu Fall Meeting Abstracts, Dec 1, 2006

A large amount of freshwater, mostly of riverine origin, flows along the southern side of Hudson ... more A large amount of freshwater, mostly of riverine origin, flows along the southern side of Hudson Strait and into the Labrador Sea. Here it combines with the fresh outflow from Davis Strait and merges into the Labrador Current, whose fresh surface layers flow close to the deep convection region of the Labrador Sea. Thus, variations in the outflow from Hudson Strait have the potential to impact dense water formation in the Labrador Sea. A comparison of year-long mooring array data from 1986-1987 and from 2004-2005 shows a significant decrease in the freshwater outflow from Hudson Strait (accompanied by an increase in the heat transport). Such a change is in agreement with the observed decreasing trend in river input into the Hudson Bay System and with the decreasing trend in sea-ice cover of the region over the last 20 years. The fact that the changes in the mooring data do not simply reflect interannual variations is supported by the analysis of hydrographic data from the upstream Hudson Bay System.

Recent changes in climate conditions in several regions of the globe raise concerns about ecosyst... more Recent changes in climate conditions in several regions of the globe raise concerns about ecosystem resilience and sustainability of ecosystem services. We examine oceanographic responses to these climate changes in four high latitude regions of the Northern Hemisphere, two in the Pacific (Bering Sea and Gulf of Alaska) and two in the Atlantic (Georges Bank/Gulf of Maine and the Barents/Norwegian Seas). Air temperature, heat fluxes and wind forcing over the four regions are examined. The effects of these on the oceanography of the regions are then determined, compared and contrasted, including changes in ocean temperatures, salinities, stratification, and circulation patterns. In addition, changes in seasonal sea ice cover are compared between the two regions where it occurs (Bering and Barents seas). Changes in temperature and salinity are examined as a function of latitude and compared to expected changes (increasing temperature and decreasing salinities in the north). The importa...

Deep Sea Res Pt Ii Top St Oce, 2007

Canadian Journal of Fisheries and Aquatic Sciences, 2001

Physical, chemical, and biological data collected on the Labrador Shelf in September 1985 are use... more Physical, chemical, and biological data collected on the Labrador Shelf in September 1985 are used to examine a hypothesis that the nutrient influx from Hudson Strait increases primary production on the northern shelf and this supports a "conveyor belt" food chain as the community is transported southward by the mean circulation. This hypothesized influx of production was proposed to account for the higher fish abundance on the southern Labrador Shelf. If true, the hypothesis suggests that the relative importance of higher trophic levels generally should increase southeastward along the shelf. Our results confirm that high nutrient levels occur on the northern Labrador Shelf in summer because of continuous advection of nutrients from Hudson Strait and this enhances local plankton production. However, nutrient, chlorophyll a, plankton species, and biomass spectra distributions generally do not support the idea that a developing food chain is advected progressively southward along the shelf. The large fish population on the southern Labrador Shelf appears to have been more dependent on production supported by local upwelling around Hamilton Bank than on food advected from the north.