scholarly journals Oceanographic and meteorological effects on autumn sea-ice distribution in the western Arctic

1991 ◽  
Vol 15 ◽  
pp. 171-177 ◽  
Author(s):  
Robin D. Muench ◽  
Carol H. Pease ◽  
Sigrid A. Salo
Keyword(s):  
Sea Ice ◽  
Chukchi Sea ◽  
Meteorological Data ◽  
Coastal Current ◽  
Ice Melt ◽  
Northern Bering Sea ◽  
Pack Ice ◽  
Edge Location ◽  
Western Arctic ◽  
Ice Edge

Oceanographic, meteorological and sea-ice data were obtained from the northern Bering Sea and Chukchi Sea during the autumns of 1987 and 1988. Ice-edge location was observed from ships and via AVHRR satellite data, and ice-drift information was obtained from ARGOS-tracked drift buoys. Meteorological data were obtained from ships, from an ARGOS-tracked meteorological station and from synoptic charts. The ice edge was significantly farther south in 1988 than during other years and impacted the Alaskan coastline. In 1987, the ice edge was, conversely, anomalously far north. Ice melt-back in certain regions, such as along the Alaskan coast and in Herald Canyon, was due to input from warm ocean currents. The larger-scale interannual differences in ice extent were, however, due to interannual differences in the regional winds. In particular, the anomalous and extreme southward extent of the ice edge during 1988 was due to northerly to northwesterly winds, which held the summer pack ice against the the beach. Meltwater from this ice salt-stratified the upper water column, so that the ice eventually became effectively insulated against vertical flux of heat from the underlying warm water in the coastal current.

scholarly journals Oceanographic and meteorological effects on autumn sea-ice distribution in the western Arctic

1991 ◽  
Vol 15 ◽  
pp. 171-177 ◽  
Author(s):  
Robin D. Muench ◽  
Carol H. Pease ◽  
Sigrid A. Salo
Keyword(s):  
Sea Ice ◽  
Chukchi Sea ◽  
Meteorological Data ◽  
Coastal Current ◽  
Ice Melt ◽  
Northern Bering Sea ◽  
Pack Ice ◽  
Edge Location ◽  
Western Arctic ◽  
Ice Edge

Oceanographic, meteorological and sea-ice data were obtained from the northern Bering Sea and Chukchi Sea during the autumns of 1987 and 1988. Ice-edge location was observed from ships and via AVHRR satellite data, and ice-drift information was obtained from ARGOS-tracked drift buoys. Meteorological data were obtained from ships, from an ARGOS-tracked meteorological station and from synoptic charts. The ice edge was significantly farther south in 1988 than during other years and impacted the Alaskan coastline. In 1987, the ice edge was, conversely, anomalously far north. Ice melt-back in certain regions, such as along the Alaskan coast and in Herald Canyon, was due to input from warm ocean currents. The larger-scale interannual differences in ice extent were, however, due to interannual differences in the regional winds. In particular, the anomalous and extreme southward extent of the ice edge during 1988 was due to northerly to northwesterly winds, which held the summer pack ice against the the beach. Meltwater from this ice salt-stratified the upper water column, so that the ice eventually became effectively insulated against vertical flux of heat from the underlying warm water in the coastal current.

scholarly journals Low <i>p</i>CO<sub>2</sub> under sea-ice melt in the Canada Basin of the western Arctic Ocean

2017 ◽  
Vol 14 (24) ◽  
pp. 5727-5739 ◽  
Author(s):  
Naohiro Kosugi ◽  
Daisuke Sasano ◽  
Masao Ishii ◽  
Shigeto Nishino ◽  
Hiroshi Uchida ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Arctic Ocean ◽  
Net Primary Production ◽  
Chukchi Sea ◽  
Canada Basin ◽  
Western Arctic Ocean ◽  
Riverine Discharge ◽  
Ice Melt ◽  
Western Arctic

Abstract. In September 2013, we observed an expanse of surface water with low CO2 partial pressure (pCO2sea) (< 200 µatm) in the Chukchi Sea of the western Arctic Ocean. The large undersaturation of CO2 in this region was the result of massive primary production after the sea-ice retreat in June and July. In the surface of the Canada Basin, salinity was low (< 27) and pCO2sea was closer to the air–sea CO2 equilibrium (∼  360 µatm). From the relationships between salinity and total alkalinity, we confirmed that the low salinity in the Canada Basin was due to the larger fraction of meltwater input (∼  0.16) rather than the riverine discharge (∼  0.1). Such an increase in pCO2sea was not so clear in the coastal region near Point Barrow, where the fraction of riverine discharge was larger than that of sea-ice melt. We also identified low pCO2sea (< 250 µatm) in the depth of 30–50 m under the halocline of the Canada Basin. This subsurface low pCO2sea was attributed to the advection of Pacific-origin water, in which dissolved inorganic carbon is relatively low, through the Chukchi Sea where net primary production is high. Oxygen supersaturation (> 20 µmol kg−1) in the subsurface low pCO2sea layer in the Canada Basin indicated significant net primary production undersea and/or in preformed condition. If these low pCO2sea layers surface by wind mixing, they will act as additional CO2 sinks; however, this is unlikely because intensification of stratification by sea-ice melt inhibits mixing across the halocline.

scholarly journals The interplay of dynamic and thermodynamic processes in driving the ice-edge location in the Southern Ocean

2011 ◽  
Vol 52 (57) ◽  
pp. 27-34 ◽  
Author(s):  
R.P. Stevens ◽  
P. Heil
Keyword(s):  
Sea Ice ◽  
Air Temperature ◽  
Freezing Point ◽  
Ice Growth ◽  
Ice Melt ◽  
Ice Concentration ◽  
Edge Location ◽  
Ice Edge ◽  
Ice Production ◽  
Thermodynamic Processes

AbstractA stand-alone sea-ice model (CICE4) was used to investigate the physical processes affecting the ice-edge location. Particular attention is paid to the relative contributions of dynamic and thermodynamic processes in advancing the ice edge equatorward during ice growth. Results from 10 years of an 11 year numerical simulation have been verified against satellite observations from 1998 to 2007. the autumn advance of the sea-ice edge is primarily due to thermodynamic processes, with significant dynamic contributions limited to regions such as 60–70˚ E and 310–340˚ E. In the dynamically dominated regions, winds with a southerly component cause equatorward ice advection but also induce thermodynamic growth of new ice, which occurs well poleward of the 15% ice-concentration contour where air temperature is lowest. As the ice moves into warmer water it melts, hence extending equatorward the region with ocean mixed layer at freezing point. This accelerates the northward progression of the ice edge and permits thermodynamic ice growth as soon as the air temperature reaches below the ocean freezing point. In regions where thermodynamic processes are dominant (e.g. 340–40˚ E), maximum ice production occurs just poleward of the 15% ice-concentration contour, where thin sea ice is prevalent. In these longitude bands, autumn ice melt is generally absent at the ice edge due to ineffective equatorward ice advection.

scholarly journals Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

2015 ◽  
Vol 12 (22) ◽  
pp. 18661-18691 ◽  
Author(s):  
H. Sasaki ◽  
K. Matsuno ◽  
A. Fujiwara ◽  
M. Onuka ◽  
A. Yamaguchi ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Mass ◽  
High Salinity ◽  
Chukchi Sea ◽  
Bottom Layer ◽  
Sea Ice Extent ◽  
High Salinity Water ◽  
Explanatory Variables ◽  
Northern Bering Sea ◽  
Salinity Water

Abstract. The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

scholarly journals Coastal acidification induced by biogeochemical processes driven by sea-ice melt in the western Arctic ocean

Polar Science ◽  
2020 ◽  
Vol 23 ◽  
pp. 100504
Author(s):  
Di Qi ◽  
Baoshan Chen ◽  
Liqi Chen ◽  
Hongmei Lin ◽  
Zhongyong Gao ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Biogeochemical Processes ◽  
Western Arctic Ocean ◽  
Ice Melt ◽  
Western Arctic ◽  
Coastal Acidification

scholarly journals Comparison of sea-ice extent and ice-edge location estimates from passive microwave and enhanced-resolution scatterometer data

2008 ◽  
Vol 48 ◽  
pp. 65-70 ◽  
Author(s):  
Walter N. Meier ◽  
Julienne Stroeve
Keyword(s):  
Sea Ice ◽  
Resolution Enhancement ◽  
Passive Microwave ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Local Conditions ◽  
Enhanced Resolution ◽  
Edge Location ◽  
Ice Conditions ◽  
Ice Edge

AbstractPassive microwave sea-ice concentration fields provide some of the longest-running and most consistent records of changes in sea ice. Scatterometry-based sea-ice fields are more recently developed data products, but now they provide a record of ice conditions spanning several years. Resolution enhancement techniques applied to scatterometer fields provide much higher effective resolutions (~10 km) than are available from standard scatterometer and passive microwave fields (25–50 km). Here we examine ice-extent fields from both sources and find that there is general agreement between scatterometer data and passive microwave fields, though scatterometer estimates yield substantially lower ice extents during winter. Comparisons with ice-edge locations estimated from AVHRR imagery indicate that enhanced scatterometer data can sometimes provide an improved edge location, but there is substantial variation in the results, depending on the local conditions. A blended product, using both scatterometer and passive microwave data, could yield improved results.

Early winter ice and snow thickness distribution, ice structure and development of the western Ross Sea pack ice between the ice edge and the Ross Ice Shelf

1997 ◽  
Vol 9 (2) ◽  
pp. 188-200 ◽  
Author(s):  
Martin O. Jeffries ◽  
Ute Adolphs
Keyword(s):  
Sea Ice ◽  
Layer Thickness ◽  
Ross Sea ◽  
Ice Thickness ◽  
First Year ◽  
Ross Ice Shelf ◽  
Antarctic Sea Ice ◽  
Pack Ice ◽  
Ice Edge ◽  
Snow And Ice

A study of early winter first-year sea ice conditions and development in the western Ross Sea in May and June 1995 included measurements of snow and ice thickness, freeboard, ice core structure and stable isotopic composition. These variables showed strong spatial variability between the Ross Ice Shelf and the ice edge 1400 km to the north, and indicate that the development of the Ross Sea pack ice is quite different from that observed in other Antarctic sea ice zones. The thinnest snow and ice occurred in a 200 km wide coastal zone. The thickest snow and ice were observed in a continental shelf zone 200–600 km from the coast where the average ice thickness (0.8 m) determined by drilling is as thick as first-year sea ice later in winter elsewhere in Antarctica. A zone of moderate snow and ice thickness occurred on the deep ocean from 600 km to the ice edge at 1400 km. Thermodynamic thickening of the ice in the inner pack ice, <800 km from the coast, was dominated by congelation ice growth, which occurred in a greater amount (65%) and in thicker layers (mean: 20 cm) than was observed in the outer pack ice >800 km from the coast (amount: 22%; mean layer thickness: 12 cm) and elsewhere in the Antarctic pack ice. The preponderance of congelation ice in the inner pack ice might be due to a low oceanic heat flux on the Ross Sea continental shelf, and a colder, less stormy environment which favours the more frequent and prolonged calm conditions necessary for significant congelation ice growth. In the outer pack ice, thermodynamic thickening occurred mainly by snow ice formation (mean layer thickness: 20 cm) while dynamic processes, i.e., rafting and ridging, caused the thickening of frazil ice and columnar ice (mean layer thickness: 14 cm and 12 cm respectively). A greater amount of snow ice (37%) occurred in the outer pack ice than in the inner pack ice (15%), and both values indicate that in the Ross Sea, unlike other Antarctic sea ice zones, there can be significant seawater flooding of the snow/ice interface and snow ice formation before midwinter.

scholarly journals Impact of a warm anomaly in the Pacific Arctic region derived from time-series export fluxes

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255837
Author(s):  
Catherine Lalande ◽  
Jacqueline M. Grebmeier ◽  
Andrew M. P. McDonnell ◽  
Russell R. Hopcroft ◽  
Stephanie O’Daly ◽  
...  
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Chukchi Sea ◽  
Arctic Region ◽  
Ice Cover ◽  
Biological Pump ◽  
Northern Bering Sea ◽  
Pacific Waters ◽  
The Pacific ◽  
The Impact

Unusually warm conditions recently observed in the Pacific Arctic region included a dramatic loss of sea ice cover and an enhanced inflow of warmer Pacific-derived waters. Moored sediment traps deployed at three biological hotspots of the Distributed Biological Observatory (DBO) during this anomalously warm period collected sinking particles nearly continuously from June 2017 to July 2019 in the northern Bering Sea (DBO2) and in the southern Chukchi Sea (DBO3), and from August 2018 to July 2019 in the northern Chukchi Sea (DBO4). Fluxes of living algal cells, chlorophyll a (chl a), total particulate matter (TPM), particulate organic carbon (POC), and zooplankton fecal pellets, along with zooplankton and meroplankton collected in the traps, were used to evaluate spatial and temporal variations in the development and composition of the phytoplankton and zooplankton communities in relation to sea ice cover and water temperature. The unprecedented sea ice loss of 2018 in the northern Bering Sea led to the export of a large bloom dominated by the exclusively pelagic diatoms Chaetoceros spp. at DBO2. Despite this intense bloom, early sea ice breakup resulted in shorter periods of enhanced chl a and diatom fluxes at all DBO sites, suggesting a weaker biological pump under reduced ice cover in the Pacific Arctic region, while the coincident increase or decrease in TPM and POC fluxes likely reflected variations in resuspension events. Meanwhile, the highest transport of warm Pacific waters during 2017–2018 led to a dominance of the small copepods Pseudocalanus at all sites. Whereas the export of ice-associated diatoms during 2019 suggested a return to more typical conditions in the northern Bering Sea, the impact on copepods persisted under the continuously enhanced transport of warm Pacific waters. Regardless, the biological pump remained strong on the shallow Pacific Arctic shelves.

scholarly journals Year-round pack ice in the Weddell Sea, Antarctica: response and sensitivity to atmospheric and oceanic forcing

1997 ◽  
Vol 25 ◽  
pp. 269-275 ◽  
Author(s):  
Cathleen A. Geiger ◽  
Stephen F. Ackley ◽  
William D. Hibler
Keyword(s):  
Heat Flux ◽  
Relative Humidity ◽  
Sea Ice ◽  
Ocean Circulation ◽  
Weddell Sea ◽  
Dynamic Responses ◽  
Actual System ◽  
Coupled Models ◽  
Pack Ice ◽  
Ice Edge

Using a dynamic-thermodynamic numerical sea-ice model, external oceanic and atmospheric forcings on sea ice in the Weddell Sea are examined to identify physical processes associated with the seasonal cycle of pack ice, and to identify further the parameters that coupled models need to consider in predicting the response of the pack ice to climate and ocean-circulation changes. In agreement with earlier studies, the primary influence on the winter ice-edge maximum extent is air temperature. Ocean heat flux has more impact on the minimum ice-edge extent and in reducing pack-ice thickness, especially in the eastern Weddell Sea. Low relative humidity enhances ice growth in thin ice and open-water regions, producing a more realistic ice edge along the coastal areas of the western Weddell Sea where dry continental air has an impact. The modeled extent of the Weddell summer pack is equally sensitive to ocean heat flux and atmospheric relative humidity variations with the more dynamic responses being from the atmosphere. Since the atmospheric regime in the eastern Weddell is dominated by marine intrusions from lower latitudes, with high humidity already, it is unlikely that either the moisture transport could be further raised or that it could be significantly lowered because of its distance from the continent (the lower humidity source). Ocean heat-transport variability is shown to lead to overall ice thinning in the model response and is a known feature of the actual system, as evidenced by the occurrence of the Weddell Polynya in the mid 1970s.

scholarly journals Low <i>p</i>CO<sub>2</sub> under sea-ice melt in the Canada Basin of the western Arctic Ocean

2017 ◽  
Author(s):  
Naohiro Kosugi ◽  
Daisuke Sasano ◽  
Masao Ishii ◽  
Shigeto Nishino ◽  
Hiroshi Uchida ◽  
...  
Keyword(s):  
Surface Water ◽  
Sea Ice ◽  
Partial Pressure ◽  
Arctic Ocean ◽  
Canada Basin ◽  
Western Arctic Ocean ◽  
Co2 Partial Pressure ◽  
Ice Melt ◽  
Low Co2 ◽  
Western Arctic

Abstract. In September 2013, we observed an expanse of surface water with low CO2 partial pressure (pCO2sea) (

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