Physical processes within the North Water (NOW) polynya

Barber, David G.; Marsden, R. F.; Minnett, Peter J.; Ingram, Grant; Fortier, Louis

doi:10.1080/07055900.2001.9649673

Cited by 47 publications

(31 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The North Water polynya is also a sensible heat polynya where some oceanic upwelling results in some ice melt and thinner ice [ Morales Maqueda et al , 2004]. This polynya has ice concentrations of 60–80% in the winter months, with the ice being young, thin and thin/medium first‐year ice [ Barber et al , 2001a; Gloersen et al , 1992]. These features, along with synoptic conditions, cause the North Water polynya to open and close in a rhythmic fashion for all but the summer months when the region is ice‐free [ Morales Maqueda et al , 2004].…”

Section: Introductionmentioning

confidence: 99%

Moisture fluxes derived from EOS aqua satellite data for the north water polynya over 2003–2009

et al. 2012

View full text Add to dashboard Cite

[1] Satellite data were applied to calculate the moisture flux from the North Water polynya during a series of events spanning [2003][2004][2005][2006][2007][2008][2009]. The fluxes were calculated using bulk aerodynamic formulas with the stability effects according to the Monin-Obukhov similarity theory. Input parameters were taken from three sources: air relative humidity, air temperature, and surface temperature from the Atmospheric Infrared Sounder (AIRS) on board NASA's Earth Observing System (EOS) Aqua satellite, sea ice concentration from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E, also on board Aqua), and wind speed from the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis. Our results show the progression of the moisture fluxes from the polynya during each event, as well as their atmospheric effects after the polynya has closed up. These results were compared to results from studies on other polynyas and fall within one standard deviation of the moisture flux estimates from these studies. Although the estimated moisture fluxes over the entire study region from AIRS are smaller in magnitude than those from ERA-Interim, they are more accurate owing to improved temperature and relative humidity profiles and ice concentration estimates over the polynya. Error estimates were calculated to be 5.56 Â 10 À3 g m À2 s À1, only 25% of the total moisture flux, thus suggesting that AIRS and AMSR-E can be used with confidence to study smaller-scale features in the Arctic sea ice pack and can capture their atmospheric effects. These findings bode well for larger-scale studies of moisture fluxes over the entire Arctic Ocean and the thinning ice pack.

show abstract

Section: Introductionmentioning

confidence: 99%

Moisture fluxes derived from EOS aqua satellite data for the north water polynya over 2003–2009

et al. 2012

View full text Add to dashboard Cite

show abstract

“…During the early winter, pack ice carried south through Kane Basin becomes congested and forms a blockage, or ice bridge, across the narrow head of Smith Sound. Newly formed ice is then swept southward by currents and prevailing winds [ Nutt , 1969; Barber et al , 2001]. Figure 1 is a satellite image of the NOW.…”

Section: Introductionmentioning

confidence: 99%

Arctic waters and marginal ice zones: A composite Arctic sea surface temperature algorithm using satellite thermal data

Vincent¹,

Marsden²,

Minnett³

et al. 2008

J. Geophys. Res.

View full text Add to dashboard Cite

[1] The retrieval of Arctic sea surface temperatures (SSTs) using satellite radiometric imagery has not been well documented owing to the paucity of match-ups with in situ data. SST algorithms developed in temperate regions lead to positive biases in high latitudes due to an overestimation of atmospheric IR absorption. The composite arctic sea surface temperature algorithm (CASSTA) presented in this paper was developed from concurrent satellite and shipborne radiometric data collected in the North Water Polynya between April and July 1998. This algorithm considers three temperature regimes: seawater above freezing, the transition zones of water and ice, and primarily ice. These regimes, which are determined by advanced very high resolution radiometer (AVHRR) calibrated brightness temperatures, require different calculations for temperature estimates. For seawater above freezing, a specific Arctic SST algorithm was produced through a linear regression of AVHRR against in situ data. Areas consisting mainly of ice use an established ice surface temperature (IST) algorithm. The transition zone uses a combination of the Arctic SST and IST algorithms. CASSTA determines the Channel 4 brightness temperature for each pixel in a calibrated AVHRR image and then applies the appropriate algorithm to create a thermal image. The mean deviation of CASSTA compared to in situ data was 0.17 K with a standard deviation of 0.21 K. This represents a significant improvement over SST values using McClain coefficients for temperate waters, which overestimate the same data set by an average of 2.40 K. Application of CASSTA to the North Water imagery gives superior results compared to existing SST or IST algorithms.Citation: Vincent, R. F., R. F. Marsden, P. J. Minnett, K. A. M. Creber, and J. R. Buckley (2008), Arctic waters and marginal ice zones: A composite Arctic sea surface temperature algorithm using satellite thermal data,

show abstract

“…Fast-ice persists for the remainder of the year. The transition between mobile-ice and fast-ice conditions is precipitated by the formation of an ice bridge across Smith Sound (Dunbar, 1973;Melling, 2000;Barber et al, 2001;Kwok, 2005;Dumont et al, 2009;Kwok et al, 2010). Such a bridge, anchored to the coasts of Greenland and Ellesmere Island, can resist the forces of tidal current and wind for many months (Samelson et al, 2006;Dumont et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Geostrophic ocean currents and freshwater fluxes across the Canadian polar shelf via Nares Strait

Rabe¹,

Johnson²,

Münchow³

et al. 2012

J Mar Res

View full text Add to dashboard Cite

This study discusses geostrophic ocean currents and fluxes through Nares Strait, one of the major straits connecting the Arctic Ocean to the North Atlantic across the Canadian polar shelf. Between 2003 and 2006, instruments were installed on subsea moorings to measure conductivity, temperature, pressure and velocity at high temporal and spatial resolution across the 400-m-deep strait.Here we present estimates of the variable volume and liquid freshwater fluxes, derived by geostrophic calculation, through the fraction of the cross section measured by the array. The array of conductivity-temperature recorders spanned 30 km of a 38-km-wide section between 30-and 200-m depth. This domain is 48% of the total cross-sectional area, and 74% of the cross-sectional area above 200-m depth. We demonstrate the importance of the seasonal alternation between land-fast and mobile-ice conditions, which has a strong influence on the structure of the geostrophic flow and the fluxes carried by it.The three-year mean geostrophic freshwater flux through the measured domain was 20 ± 3 mSv (relative to 34.8 psu) and no less than 28 mSv if extrapolated to the surface. No significant trend over three years was detected, but the flux of freshwater through the measured domain was about 20% larger when ice was moving than when it was land-fast, with a maximum difference between individual ice seasons of 40%. Geostrophic freshwater flux in Nares Strait was forced by both wind and alongchannel pressure difference during mobile-ice periods, and by along-channel pressure difference only under land-fast ice. Local winds and along-channel pressure differences explained 80% of the flux variance.Geostrophic volume flux through the measured domain was less strongly influenced by the state of the ice; its three-year mean was 0.47 ± 0.05 Sv, with a statistically significant increase of 15 ± 4% over this time. Geostrophic velocity was highly variable in space and time. The flow structure changed from a pattern with a surface jet in the center of the channel during mobile-ice conditions to another with a subsurface maximum in velocity adjacent to Ellesmere Island during fast-ice conditions. Over the three years, a second jet developed adjacent to the Ellesmere coast during mobile-ice regimes. Strong freshwater incursions synchronous with strong wind events were observed during mobile-ice seasons in the western half of the strait.

show abstract

Physical processes within the North Water (NOW) polynya

Cited by 47 publications

References 13 publications

Moisture fluxes derived from EOS aqua satellite data for the north water polynya over 2003–2009

Moisture fluxes derived from EOS aqua satellite data for the north water polynya over 2003–2009

Arctic waters and marginal ice zones: A composite Arctic sea surface temperature algorithm using satellite thermal data

Geostrophic ocean currents and freshwater fluxes across the Canadian polar shelf via Nares Strait

Contact Info

Product

Resources

About