The Effect of Protracted Spring Thaws on Ice Conditions in Hudson Bay *

1952 ◽  
Vol 33 (3) ◽  
pp. 101-106 ◽  
Author(s):  
G. A. Mackay
Keyword(s):  
Open Water ◽  
Weather Conditions ◽  
Ice Cover ◽  
Hudson Bay ◽  
Synoptic Weather ◽  
Ice Conditions ◽  
The Mean ◽  
Abnormal Weather

The extent of ice cover in Hudson Bay was investigated during the Spring of 1948 by the RCAF and interested governmental departments. A series of reconnaissance flights over the Bay in March and April disclosed that it was virtually ice-bound from shore to shore. Large areas of open water were observed during the period May 3rd to May 6th. An inspection of the synoptic weather charts disclosed that weather conditions over the Bay both prior to and during this period were abnormal. This immediately suggests that the ice conditions observed might not be representative. For an appraisal of the observations it is necessary to determine the effects of the abnormal weather on the ice. The observed ice conditions are mentioned and the causes of open water areas briefly discussed. The severity of the winter at Churchill was investigated to determine the normalcy of the ice development. A protracted thaw over the eastern parts of Hudson Bay is disclosed by reference to the weather charts. The correlation between the mean monthly temperatures for the spring months and the date of ice clearance at Churchill Harbour is then investigated to determine the effects of a protracted thaw on the ice.

scholarly journals Sea ice cover in Isfjorden and Hornsund 2000–2014 by using remote sensing

2015 ◽  
Vol 9 (4) ◽  
pp. 4043-4066
Author(s):  
S. Muckenhuber ◽  
F. Nilsen ◽  
A. Korosov ◽  
S. Sandven
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Ice Cover ◽  
Ice Coverage ◽  
Time Period ◽  
Ice Drift ◽  
Before And After ◽  
Ice Conditions ◽  
Fast Ice ◽  
The Mean

Abstract. A satellite database including 16 555 satellite images and ice charts displaying the area of Isfjorden, Hornsund and the Svalbard region has been established with focus on the time period 2000–2014. 3319 manual interpretations of sea ice conditions have been conducted, resulting in two time series dividing the area of Isfjorden and Hornsund into "Fast ice", "Drift ice" and open "Water". The maximum fast ice coverage of Isfjorden is > 40 % in the periods 2000–2005 and 2009–2011 and stays < 30 % in 2006–2008 and 2012–2014. Fast ice cover in Hornsund reaches > 40 % in all considered years, except for 2012 and 2014, where the maximum stays < 20 %. The mean seasonal cycles of fast ice in Isfjorden and Hornsund show monthly averaged values of less than 1 % between July and November and maxima in March (Isfjorden, 35.7 %) and April (Hornsund, 42.1 %) respectively. A significant reduction of the monthly averaged fast ice coverage is found when comparing the time periods 2000–2005 and 2006–2014. The seasonal maximum decreases from 57.5 to 23.2 % in Isfjorden and from 52.6 to 35.2 % in Hornsund. A new concept, called "days of fast ice coverage" (DFI), is introduced for quantification of the interannual variation of fast ice cover, allowing for comparison between different fjords and winter seasons. Considering the time period from 1 March until end of sea ice season, the mean DFI values for 2000–2014 are 33.1 ± 18.2 DFI (Isfjorden) and 42.9 ± 18.2 DFI (Hornsund). A distinct shift to lower DFI values is observed in 2006. Calculating a mean before and after 2006 yields a decrease from 50 to 22 DFI for Isfjorden and from 56 to 34 DFI for Hornsund.

scholarly journals On the Response of a Sea-Ice Cover to Changes in Surface Temperature

1966 ◽  
Vol 6 (45) ◽  
pp. 439-442 ◽  
Author(s):  
Peter Schwerdtfeger
Keyword(s):  
Growth Rate ◽  
Sea Ice ◽  
Surface Temperature ◽  
Ice Cover ◽  
Hudson Bay ◽  
Time Separation ◽  
The Mean ◽  
Temperature And Growth

The time separation between related extremes in the values of surface temperature and growth rate of a floating ice cover are shown to depend on the mean ice temperature and thickness. A quantity termed the lag coefficient is introduced for which observations from Churchill, Hudson Bay, and Davis, Antarctica, suggest a dependence on temperature but not on geography.

scholarly journals Analysis of dynamics for anomalies of the ice cover in the Okhotsk Sea in the period from 1882 to 2015

2016 ◽  
Vol 185 (2) ◽  
pp. 228-239
Author(s):  
Vladimir M. Pishchalnik ◽  
Valery A. Romanyuk ◽  
Igor G. Minervin ◽  
Alevtina S. Batuhtina
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Regime Shift ◽  
Ice Cover ◽  
Satellite Observations ◽  
Okhotsk Sea ◽  
Ice Conditions ◽  
The Mean ◽  
Analysis Of Dynamics

The time-series for the ice cover dynamics in the Okhotsk Sea in the period from 1882 to 2015 are reconstructed on the base of shipboard, airborne, and satellite observations and measurements of the air temperature at the coastal meteorological stations. Abnormality of the ice conditions is estimated relative to the “climate norm” determined as the mean seasonal variation for the 1961-1990. Long-term variability of the ice cover is analyzed. Its regime shift with change of trend is revealed in the late 1970s - early 1980s that corresponds to the regime shift of the air temperature variability in the northern hemisphere.

scholarly journals Automated Underway Eddy Covariance System for Air–Sea Momentum, Heat, and CO2 Fluxes in the Southern Ocean

2016 ◽  
Vol 33 (4) ◽  
pp. 635-652 ◽  
Author(s):  
Brian J. Butterworth ◽  
Scott D. Miller
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Eddy Covariance ◽  
Open Water ◽  
Ice Cover ◽  
Published Data ◽  
Flow Distortion ◽  
Ice Conditions ◽  
Antarctic Research ◽  
Processing Techniques

AbstractA ruggedized closed-path eddy covariance (EC) system was designed for unattended direct measurements of air–sea momentum, heat, and CO2 flux, and was deployed on the Research Vessel Icebreaker (RV/IB) Nathaniel B. Palmer (NBP), an Antarctic research and supply vessel. The system operated for nine cruises during 18 months from January 2013 to June 2014 in the Southern Ocean and coastal Antarctica, sampling a wide variety of wind, wave, biological productivity, and ice conditions. The methods are described and the results are shown for two cruises chosen for their latitudinal range, inclusion of both open water and sea ice cover, and relatively large air–water CO2 concentration differences (ΔpCO2). Ship flow distortion was addressed by comparing mean winds, fluxes, and cospectra from an array of 3D anemometers at the NBP bow, comparing measured fluxes with bulk formulas, and implementing and evaluating several recently published data processing techniques. Quality-controlled momentum, heat, and CO2 flux data were obtained for 25% of the periods when NBP was at sea, with most (86%) of the rejected periods due to wind directions relative to the ship >±30° from the bow. In contrast to previous studies, no bias was apparent in measured CO2 fluxes for low |ΔpCO2|. The relationship between momentum flux and wind speed showed a clear dependence on the degree of sea ice cover, a result facilitated by the geographical coverage possible with a ship-based approach. These results indicate that ship-based unattended EC in high latitudes is feasible, and recommendations for deployments of underway systems in such environments are provided.

scholarly journals Multiproxy evidence of the Neoglacial expansion of Atlantic Water to eastern Svalbard: Does ancient environmental DNA complement sedimentary and microfossil records?

2019 ◽  
Author(s):  
Joanna Pawłowska ◽  
Magdalena Łącka ◽  
Małgorzata Kucharska ◽  
Jan Pawlowski ◽  
Marek Zajączkowski
Keyword(s):  
Sea Ice ◽  
Dna Sequences ◽  
Environmental Changes ◽  
Environmental Dna ◽  
Open Water ◽  
Ice Cover ◽  
Atlantic Water ◽  
Ice Coverage ◽  
Ice Conditions ◽  
Multiproxy Approach

Abstract. The main goal of this study was to reconstruct the paleoceanographic development of Storfjorden during the Neoglacial (~ 4 cal ka BP). A multiproxy approach was applied to provide evidence for interactions between the inflow of Atlantic Water (AW) and sea-ice coverage, which are the major drivers of environmental changes in Storfjorden. The sedimentary and microfossil records indicate that a major reorganization of oceanographic conditions in Storfjorden occurred at ~ 2.7 cal ka BP. A general cooling and the less pronounced presence of AW in Storfjorden during the early phase of the Neoglacial are prerequisite conditions for the formation of an extensive sea-ice cover. The period after ~ 2.7 cal ka BP was characterized by alternating short-term cooling and warming intervals. Warming was associated with pulsed inflows of AW and sea-ice melting that stimulated phytoplankton blooms and organic matter supply to the bottom. The cold phases were characterized by heavy and densely packed sea ice resulting in a decrease in productivity. The ancient environmental DNA (aDNA) records of foraminifera and diatoms reveal the timing of the major pulses of AW (~ 2.3 and ~ 1.7 cal ka BP) and the variation in sea-ice cover. The AW inflow was marked by an increase in the percentage of DNA sequences of monothalamous foraminifera associated with the presence of fresh phytodetritus, while cold and less productive intervals were marked by an increased proportion of monothalamous taxa known only from environmental sequencing. The diatom aDNA record indicates that primary production was continuous during the Neoglacial regardless of sea-ice conditions. However, the colder periods were characterized by the presence of diatom taxa associated with sea ice, whereas the present-day diatom assemblage is dominated by open-water taxa.

Courbes de remous sous les couverts de glace de la Grande Rivière

1981 ◽  
Vol 8 (3) ◽  
pp. 351-363 ◽  
Author(s):  
B. Michel ◽  
M. Drouin
Keyword(s):  
Water Flow ◽  
Open Water ◽  
Weather Conditions ◽  
Ice Cover ◽  
Time Dependent ◽  
Ice Formation ◽  
Flow Conditions ◽  
Variable Flow ◽  
Thermal Growth ◽  
Major Factors

The problem of backwater curve computations under ice covers is very complex. On top of the difficulties which are inherent to computation of backwater curves under open water flow conditions, the ice cover has to be taken into account; its thickness and roughness is time dependent because of variable flow and weather conditions. One of the major factors is the formation of hanging ice dams, especially in most northerly rivers.In this paper we present a complete method for the computation of backwater curves, based on mechanisms of ice formation: the law of equilibrium of the frontal edge, the accumulation of ice under this edge, thermal growth, and finally the equilibrium of hanging dams. The method is based upon measurements taken in the La Grande River.

scholarly journals Multiproxy evidence of the Neoglacial expansion of Atlantic Water to eastern Svalbard

2020 ◽  
Vol 16 (2) ◽  
pp. 487-501 ◽  
Author(s):  
Joanna Pawłowska ◽  
Magdalena Łącka ◽  
Małgorzata Kucharska ◽  
Jan Pawlowski ◽  
Marek Zajączkowski
Keyword(s):  
Sea Ice ◽  
Dna Sequences ◽  
Environmental Changes ◽  
Environmental Dna ◽  
Open Water ◽  
Ice Cover ◽  
Atlantic Water ◽  
Arctic Water ◽  
Ice Coverage ◽  
Ice Conditions

Abstract. The main goal of this study is to reconstruct the paleoceanographic development of Storfjorden during the Neoglacial (∼4 cal ka BP). Storfjorden is one of the most important brine factories in the European Arctic and is responsible for deepwater production. Moreover, it is a climate-sensitive area influenced by two contrasting water masses: warm and saline Atlantic Water (AW) and cold and fresh Arctic Water (ArW). Herein, a multiproxy approach was applied to provide evidence for existing interactions between the inflow of AW and sea ice coverage, which are the major drivers of environmental changes in Storfjorden. The sedimentary and microfossil records indicate that a major reorganization of oceanographic conditions in Storfjorden occurred at ∼2.7 cal ka BP. The cold conditions and the less pronounced presence of AW in Storfjorden during the early phase of the Neoglacial were the prerequisite conditions for the formation of extensive sea ice cover. The period after ∼2.7 cal ka BP was characterized by alternating short-term cooling and warming intervals. Warming was associated with pulsed inflows of AW and sea ice melting that stimulated phytoplankton blooms and organic matter supply to the bottom. The cold phases were characterized by heavy and densely packed sea ice, resulting in decreased productivity. The ancient environmental DNA (aDNA) records of foraminifera and diatoms support the occurrence of the major pulses of AW (∼2.3 and ∼1.7 cal ka BP) and the variations in sea ice cover. The episodes of enhanced AW inflow were marked by an increase in the percentage of DNA sequences of monothalamous foraminifera associated with the presence of fresh phytodetritus. Cold and less productive intervals were marked by an increased proportion of monothalamous taxa known only from environmental sequencing. The diatom aDNA record indicates that primary production was continuous during the Neoglacial, regardless of the sea ice conditions. However, the colder periods were characterized by the presence of diatom taxa associated with sea ice, whereas the present-day diatom assemblage is dominated by open-water taxa.

The effect of ice conditions in northern Hudson Bay on breeding by Thick-billed Murres (Uria lomvia)

1998 ◽  
Vol 76 (3) ◽  
pp. 480-492 ◽  
Author(s):  
Anthony J Gaston ◽  
Mark Hipfner
Keyword(s):  
Body Mass ◽  
Egg Size ◽  
Annual Variation ◽  
Ice Cover ◽  
Hudson Bay ◽  
Uria Lomvia ◽  
Marine Food Web ◽  
Adult Body Mass ◽  
Ice Conditions ◽  
Marine Food

We compared annual indices of breeding by Thick-billed Murres, Uria lomvia, at a colony in northern Hudson Bay with annual variation in the extent of sea-ice cover during May and June, the period when birds arrive and initiate breeding. Greater ice cover was associated with delayed breeding and lower attendance rates at the colony during the early incubation period (late June). We detected no effect on egg size, reproductive success, or adult body mass. The extent of ice cover in May was positively correlated with the proportion of Arctic cod fed to nestlings, and in June with the proportion of capelin in the rest of the diet. There was a positive correlation between the proportion of capelin in the chick diet and chick body mass at 14 days of age. We attribute the delay in laying during years of heavy ice cover to the reduced area available for foraging close to the colony. Prolonged persistence of ice, though delaying the onset of laying, may benefit the birds later in the season, as they forage preferentially in the vicinity of ice. We suggest that the strong relationships we observed between the extent of ice cover and aspects of the breeding biology of Thick-billed Murres may apply to other Arctic-nesting seabirds and may reflect conditions affecting the entire marine food web.

scholarly journals Discontinuous change in ice cover in Hudson Bay in the 1990s and some consequences for marine birds and their prey

2012 ◽  
Vol 69 (7) ◽  
pp. 1218-1225 ◽  
Author(s):  
Anthony J. Gaston ◽  
Paul A. Smith ◽  
Jennifer F. Provencher
Keyword(s):  
Open Water ◽  
Ice Cover ◽  
Step Change ◽  
Hudson Bay ◽  
Discontinuous Change ◽  
Marine Birds ◽  
Arctic Cod ◽  
Capelin Mallotus Villosus ◽  
Arctic Ice ◽  
Ecosystem Changes

Abstract Gaston A. J., Smith, P. A., and Provencher, J. F. 2012. Discontinuous change in ice cover in Hudson Bay in the 1990s and some consequences for marine birds and their prey. – ICES Journal of Marine Science, 69: . Arctic ice cover has changed strikingly since the mid-1990s, with the minimum ice extent in the northern hemisphere diminishing by 8.5% per decade since 1981. In the Canadian Arctic, ice cover in June and November showed a step change in the mid-1990s, with little reduction before that. There was a similar step change in northern Hudson Bay. A long-term dataset on marine birds at Coats Island, Nunavut, revealed that many changes in seabird biology also exhibited an abrupt change at, or soon after, the change in ice conditions. This applied to their diet that switched in the 1990s from one dominated by Arctic cod, Boreogadus saida, to one dominated by capelin, Mallotus villosus. Evidence from the proportion of Arctic cod in adult diets suggested that the length of the open-water season may be a good predictor of the switch between Arctic cod and capelin. Other changes, in nestling growth and population trend, may relate to the same ecosystem changes that led to the switch in diet. Abrupt changes, as in the breeding biology of murres at Coats Island, would seem to be characteristic of ecosystem alterations driven by climate change.

scholarly journals Enhanced thermodynamic ice growth by sea-ice deformation

1998 ◽  
Vol 27 ◽  
pp. 433-437 ◽  
Author(s):  
Petra Heil ◽  
Victoria I. Lytle ◽  
Ian Allison
Keyword(s):  
Spatial Scales ◽  
Open Water ◽  
Storm Event ◽  
Ice Growth ◽  
Synoptic Weather ◽  
Antarctic Continental Shelf ◽  
Short Period ◽  
The Mean ◽  
The Antarctic ◽  
Second Peak

Sca-icc drift and deformation were measured with an array of drifting buoys during a 1995 winter experiment off the East Antarctic continental shelf south of the Antarctic Divergence. The buoys were configured so that deformation of the icefield could be monitored on a range of spatial scales from 2 to 130 km. The mean hourly drift rate during the 3 week-long experiment was 0.21 m s−1, and the mean daily translation of the field was 17.3 km. Differential kinematic parameters calculated from the data show a very high short-term variance, indicating that high-frequency processes are dominant. Spectral analysis of the velocity data shows a major peak of the energy spectrum at the frequency of passage of synoptic weather systems, and a second peak at the inertial frequency. A major storm event occurred during the experiment. Net divergence over this phase of the experiment, as measured by a five-buoy array, is small compared to the short-period variance. This alternating divergence and convergence has a marked effect on the net ice growth. Intense freezing and rapid new ice formation occurs in the open water areas formed during divergence, and this is thickened by rafting and ridge-building during the subsequent convergence. New open water areas equivalent to 10% of the total area formed during the first phase of the experiment. A one-dimensional multilayer thermodynamic model of ice growth shows that this led to an increase of 2.8 cm in the area-averaged ice growth over a 7 day interval, which is equivalent to 40-50% of the total estimated ice growth over the region.

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