scholarly journals Robust wavebuoys for the marginal ice zone: Experiences from a large persistent array in the Beaufort Sea

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Martin J. Doble ◽  
Jeremy P. Wilkinson ◽  
Lovro Valcic ◽  
Jeremy Robst ◽  
Andrew Tait ◽  
...  
Keyword(s):  
Sea Ice ◽  
Significant Proportion ◽  
Open Water ◽  
Beaufort Sea ◽  
Ice Cover ◽  
Naval Research ◽  
Ice Dynamics ◽  
Office Of Naval Research ◽  
Marginal Ice Zone ◽  
Sample Frequency

An array of novel directional wavebuoys was designed and deployed into the Beaufort Sea ice cover in March 2014, as part of the Office of Naval Research Marginal Ice Zone experiment. The buoys were designed to drift with the ice throughout the year and monitor the expected breakup and retreat of the ice cover, forced by waves travelling into the ice from open water. Buoys were deployed from fast-and-light air-supported ice camps, based out of Sachs Harbour on Canada’s Banks Island, and drifted westwards with the sea ice over the course of spring, summer and autumn, as the ice melted, broke up and finally re-froze. The buoys transmitted heave, roll and pitch timeseries at 1 Hz sample frequency over the course of up to eight months, surviving both convergent ice dynamics and significant waves-in-ice events. Twelve of the 19 buoys survived until their batteries were finally exhausted during freeze-up in late October/November. Ice impact was found to have contaminated a significant proportion of the Kalman-filter-derived heave records, and these bad records were removed with reference to raw x/y/z accelerations. The quality of magnetometer-derived buoy headings at the very high magnetic field inclinations close to the magnetic pole was found to be generally acceptable, except in the case of four buoys which had probably suffered rough handling during transport to the ice. In general, these new buoys performed as expected, though vigilance as to the veracity of the output is required.

scholarly journals Albedo of Melting Sea Ice in the Southern Beaufort Sea

1971 ◽  
Vol 10 (58) ◽  
pp. 101-104 ◽  
Author(s):  
M.P. Langleben
Keyword(s):  
Sea Ice ◽  
Northwest Territories ◽  
Beaufort Sea ◽  
Ice Cover ◽  
Short Wave ◽  
Wave Radiation ◽  
Short Wave Radiation ◽  
Melting Period ◽  
Fast Ice ◽  
Made In

AbstractTwo Kipp hemispherical radiometers mounted back to back and suspended by an 18 m cable from a helicopter flying at an altitude of about 90 m were used to make measurements of incident and reflected short-wave radiation. The helicopter was brought to a hovering position at the instant of measurement to ensure that the radiometers were in the proper attitude and a photograph of the ice cover was taken at the same time. The observations were made in 1969 during 16 flights out of Tuktoyaktuk, Northwest Territories (lat. 69° 26’N., long. 133° 02’W.) over the fast ice extending 80 km north of Tuktoyaktuk. Values of albedo of the ice cover were found to decrease during the melting period according to the equation A = 0.59 —0.32P where P is the degree of puddling of the surface.

Increasing Multiyear Sea Ice Loss in the Beaufort Sea: A New Export Pathway for the Diminishing Multiyear Ice Cover of the Arctic Ocean

2021 ◽  
Author(s):  
David Gareth Babb ◽  
Ryan J. Galley ◽  
Stephen E. L. Howell ◽  
Jack Christopher Landy ◽  
Julienne Christine Stroeve ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Beaufort Sea ◽  
Ice Cover ◽  
The Arctic ◽  
Export Pathway ◽  
The Arctic Ocean ◽  
Multiyear Ice

The Coordinated Eastern Arctic Experiment: SPRI sea-ice studies

Polar Record ◽  
1990 ◽  
Vol 26 (158) ◽  
pp. 203-210 ◽  
Author(s):  
R. G. Williams ◽  
N. R. Davis ◽  
S. C. Moore
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Strong Coupling ◽  
Time Scales ◽  
Internal Waves ◽  
Naval Research ◽  
Coupling Mechanism ◽  
Office Of Naval Research ◽  
Polar Research Institute ◽  
Horizontal Strain

AbstractDuring March and April 1989 a two-man team from the Scott Polar Research Institute (SPRI) and Science Applications International Corporation (SAIC) took part in the oceanography ice camp phase of the Office of Naval Research-sponsored Coordinated Eastern Arctic Experiment (CEAREX). The aim of the experiment was to measure with strainmeters and tiltmeters the interaction between oceanic internal waves and sea ice. Arrays of these instruments were deployed to measure horizontal strain and vertical tilt fields continuously over a 29-day period. The resulting time series show quite clearly internal wavelike activity indicating that a strong coupling mechanism exists. Other interesting phenomena are evident in the data with timę-scales varying from seconds to several days.

scholarly journals Holocene variability in sea ice and primary productivity in the northeastern Baffin Bay

arktos ◽  
2020 ◽  
Vol 6 (1-3) ◽  
pp. 55-73 ◽  
Author(s):  
Jeetendra Saini ◽  
Ruediger Stein ◽  
Kirsten Fahl ◽  
Jens Weiser ◽  
Dierk Hebbeln ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Circulation ◽  
Water Discharge ◽  
Greenland Ice Sheet ◽  
Open Water ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Baffin Bay ◽  
Arctic Sea ◽  
Ice Edge

AbstractArctic sea ice is a critical component of the climate system, known to influence ocean circulation, earth’s albedo, and ocean–atmosphere heat and gas exchange. Current developments in the use of IP25 (a sea ice proxy with 25 carbon atoms only synthesized by Arctic sea ice diatoms) have proven it to be a suitable proxy for paleo-sea ice reconstructions over hundreds of thousands to even millions of years. In the NE Baffin Bay, off NW Greenland, Melville Bugt is a climate-sensitive region characterized by strong seasonal sea ice variability and strong melt-water discharge from the Greenland Ice Sheet (GIS). Here, we present a centennial-scale resolution Holocene sea ice record, based on IP25 and open-water phytoplankton biomarkers (brassicasterol, dinosterol and HBI III) using core GeoB19927-3 (73° 35.26′ N, 58° 05.66′ W). Seasonal to ice-edge conditions near the core site are documented for most of the Holocene period with some significant variability. In the lower-most part, a cold interval characterized by extensive sea ice cover and very low local productivity is succeeded by an interval (~ 9.4–8.5 ka BP) with reduced sea ice cover, enhanced GIS spring melting, and strong influence of the West Greenland Current (WGC). From ~ 8.5 until ~ 7.8 ka BP, a cooling event is recorded by ice algae and phytoplankton biomarkers. They indicate an extended sea ice cover, possibly related to the opening of Nares Strait, which may have led to an increased influx of Polar Water into NE-Baffin Bay. The interval between ~ 7.8 and ~ 3.0 ka BP is characterized by generally reduced sea ice cover with millennial-scale variability of the (late winter/early spring) ice-edge limit, increased open-water conditions (polynya type), and a dominant WGC carrying warm waters at least as far as the Melville Bugt area. During the last ~ 3.0 ka BP, our biomarker records do not reflect the late Holocene ‘Neoglacial cooling’ observed elsewhere in the Northern Hemisphere, possibly due to the persistent influence of the WGC and interactions with the adjacent fjords. Peaks in HBI III at about ~ 2.1 and ~ 1.3 ka BP, interpreted as persistent ice-edge situations, might correlate with the Roman Warm Period (RWP) and Medieval Climate Anomaly (MCA), respectively, in-phase with the North Atlantic Oscillation (NAO) mode. When integrated with marine and terrestrial records from other circum-Baffin Bay areas (Disko Bay, the Canadian Arctic, the Labrador Sea), the Melville Bugt biomarker records point to close ties with high Arctic and Northern Hemispheric climate conditions, driven by solar and oceanic circulation forcings.

scholarly journals Comparison of Sea-ice Type Identification Between Airborne Dual Frequency Passive Microwave Radiometry and Standard Laser/Infrared Techniques

1975 ◽  
Vol 15 (73) ◽  
pp. 225-239
Author(s):  
S. G. Tooma ◽  
R. A. Mennella ◽  
J. P. Hollinger ◽  
R. D. Ketchum
Keyword(s):  
Sea Ice ◽  
Ground Truth ◽  
Open Water ◽  
Weather Conditions ◽  
Passive Microwave ◽  
Single Frequency ◽  
Naval Research ◽  
First Year ◽  
Dual Frequency ◽  
Brightness Temperatures

AbstractDuring December 1973, the Naval Oceanographie Offirc (NAVOCKANO) and the Naval Research Laboratory (NRL) conducted a joint remote-sensing experiment over the sea-ice fields off Scoresby Sound on the east coast of Greenland using NAVOCEANO’s RP3-A Birdseye aircraft, laser profiler, and infrared scanner, and NRL’s 19.34 and 31.0 GHz nadir-looking radiometers. The objectives of this mission were: (1) to develop skills for interpreting sea-ice passive microwave data. (2) to expand, if possible, the two-category capability (multi-year ice and first-year ice) of passive microwave sensors over sea ice, (3) to compare two frequencies (19 and 31 GHz) to determine which may be more useful in a scanning radiometer now under development at NRL, and (4) to determine the value of multi-frequency as compared to single-frequency study of sea ice.Since, because of darkness and remoteness, no photography or in situ ground truth were possible for this mission, it was necessary to rely on the interpretations of the laser and infrared (IR) data to evaluate the performance of the microwave radiometers. Fortunately, excellent laser and IR data were collected, and a confident description of the ice overflown was possible.Five ice conditions: (1) open water/new ice, (2) smooth first-year ice, (3) ridged first-year ice, (4) multi-year ice, and (5) a higher brightness temperature form of multi-year ice interpreted as second-year ice were identifiable, regardless of weather conditions, by comparing the average of the two microwave brightness temperatures at the two frequencies with their difference.

scholarly journals Seasonal Variations In The Surface Energy Exchanges Over Antarctic Sea Ice and Coastal Waters

1982 ◽  
Vol 3 ◽  
pp. 12-16 ◽  
Author(s):  
I. Allison ◽  
C.M. Tivendale ◽  
G.J. Akerman ◽  
J.M. Tann ◽  
R.H. Wills
Keyword(s):  
Heat Transfer ◽  
Sea Ice ◽  
Seasonal Variations ◽  
Lower Boundary ◽  
Open Water ◽  
Ice Cover ◽  
Turbulent Fluxes ◽  
Turbulent Heat ◽  
Radiative Heat Loss ◽  
Antarctic Sea Ice

Seasonal variations in radiative and turbulent fluxes at the surface of, and in the heat transfer within, sea ice are discussed from results of energy balance studies at a site of annual ice cover near Mawson, Antarctica. In mid-summer, the open water gains heat mostly by radiation but by early February the ocean is cooling predominantly by strong turbulent losses, with some radiative heat loss occurring also by March. When an ice cover forms, turbulent fluxes decrease from several 100 W m−2over open water to only 40 w m−2over ice less than 0.2 m thick and even less over thicker ice.Net radiative losses over mature ice in mid-winter are balanced mostly by conduction through the ice cover but with some turbulent heat gain at the surface. By mid-spring, there is a net radiative gain, the turbulent fluxes are again outgoing, and there is little total heat transfer through the ice. At break-out, the albedo increase from ice to open water causes a large increase in the net radiative gain.At the lower boundary of the ice, the oceanic heat flux provides an important contribution. A net advection of heat into the region is shown from temperature profiles in the water under the ice. Salinity changes in the water during the period of ice melt are also discussed.

scholarly journals Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1A/B

2020 ◽  
Vol 61 (82) ◽  
pp. 40-50 ◽  
Author(s):  
A. Malin Johansson ◽  
Eirik Malnes ◽  
Sebastian Gerland ◽  
Anca Cristea ◽  
Anthony P. Doulgeris ◽  
...  
Keyword(s):  
Sea Ice ◽  
Synthetic Aperture Radar ◽  
Satellite Images ◽  
Satellite Image ◽  
Open Water ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Synthetic Aperture ◽  
Envisat Asar ◽  
Aperture Radar

AbstractSynthetic Aperture Radar (SAR) satellite images are used to monitor Arctic sea ice, with systematic data records dating back to 1991. We propose a semi-supervised classification method that separates open water from sea ice and can utilise ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1 SAR images. The classification combines automatic segmentation with a manual segment selection stage. The segmentation algorithm requires only the backscatter intensities and incidence angle values as input, therefore can be used to establish a consistent decadal sea ice record. In this study we investigate the sea ice conditions in two Svalbard fjords, Kongsfjorden and Rijpfjorden. Both fjords have a seasonal ice cover, though Rijpfjorden has a longer sea ice season. The satellite image dataset has weekly to daily records from 2002 until now, and less frequent records between 1991 and 2002. Time overlap between different sensors is investigated to ensure consistency in the reported sea ice cover. The classification results have been compared to high-resolution SAR data as well as in-situ measurements and sea ice maps from Ny-Ålesund. For both fjords the length of the sea ice season has shortened since 2002 and for Kongsfjorden the maximum sea ice coverage is significantly lower after 2006.

scholarly journals Melting of Perennial Sea Ice in the Beaufort Sea Enhanced Its Impacts on Early-Winter Haze Pollution in North China after the Mid-1990s

2020 ◽  
Vol 33 (12) ◽  
pp. 5061-5080 ◽  
Author(s):  
Yuyan Li ◽  
Zhicong Yin
Keyword(s):  
Sea Ice ◽  
North China ◽  
Beaufort Sea ◽  
Gulf Of Alaska ◽  
Ice Cover ◽  
Sea Surface ◽  
Haze Pollution ◽  
Sea Surface Temperature Anomalies ◽  
Haze Days ◽  
Perennial Ice

AbstractIn recent years, haze pollution has become the most concerning environmental issue in China due to its tremendous negative effects. In this study, we focus on the enhanced responses of December–January haze days in North China to September–October sea ice in the Beaufort Sea during 1998–2015. Via both observation and numerical approaches, compared with an earlier period (1980–97), the sea ice concentration in the Beaufort Sea presented large variability during 1998–2015. During 1980–97, the Beaufort Sea was mainly covered by perennial ice, and the ablation and freezing of sea ice mainly occurred at the south edge of the Beaufort Sea. Thus, heavy sea ice in autumn induced negative sea surface temperature anomalies across the Gulf of Alaska in November. However, the colder sea surface in the Gulf of Alaska only induced a weak influence on the haze-associated atmospheric circulations. In contrast, during 1998–2015, a drastic change in sea ice existed near the center of the Arctic Ocean, due to the massive melting of multiyear sea ice in the western Beaufort Sea. The perennial ice cover in the western Beaufort Sea was replaced by seasonal ice. The broader sea ice cover resulted in positive sea surface temperature anomalies in the following November. Then, suitable atmospheric backgrounds were induced for haze pollution in December and January. Simultaneously, the response of the number of haze days over North China to sea ice cover increased. These findings were verified by the CESM-LE simulations and aided in deepening the understanding of the cause of haze pollution.

scholarly journals On the surface energy budget of sea ice

1997 ◽  
Vol 43 (143) ◽  
pp. 122-130 ◽  
Author(s):  
Gerd Wendler ◽  
Ute Adolphs ◽  
Adrian Hauser ◽  
Blake Moore
Keyword(s):  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
High Surface ◽  
Open Water ◽  
Ice Cover ◽  
Surface Energy Budget ◽  
Net Radiation ◽  
Pack Ice ◽  
Ice Concentration

AbstractThe surface energy budget was investigated during a cruise through the pack ice in the Southern Ocean. The time of observation was close to mid-summer. Some of the more important findings were: The mean albedo varied from 11 % for open water to 59% for 10/10 ice cover. Hourly values span the range from 6% (open water) to 76% (total ice cover).The net heat flux into the ocean (B) was on average 109 W m−2, If this energy were used solely for melting of sea ice, 30 mm could be melted each day.For low surface albedos (ice concentration below 7/10), the net radiation increased with decreasing cloudiness. However, the opposite was the case for a high surface albedo. The last point shows the importance of clouds on the surface energy budget. Not only should their presence or absence be known but also the reflectivity of the underlying surface, as it might change the net radiation in opposite ways.

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