scholarly journals Sediments in sea ice drive the Canada Basin surface Mn maximum: insights from an Arctic Mn ocean model

2021 ◽  
Author(s):  
Birgit Rogalla ◽  
Susan E. Allen ◽  
Manuel Colombo ◽  
Paul G. Myers ◽  
Kristin J. Orians
Keyword(s):  
Sea Ice ◽  
Ocean Model ◽  
Canada Basin ◽  
Basin Surface

Dirty sea ice drives higher Mn concentrations in the Canada Basin

2021 ◽  
Author(s):  
Birgit Rogalla ◽  
Susan E. Allen ◽  
Manuel Colombo ◽  
Paul G. Myers ◽  
Kristin J. Orians
Keyword(s):  
Sea Ice ◽  
Long Range ◽  
Sediment Resuspension ◽  
Three Dimensional ◽  
Arctic Sea Ice ◽  
Canada Basin ◽  
The Arctic ◽  
Long Range Transport ◽  
Basin Surface ◽  
Range Transport

<p>The rapidly changing conditions of the Arctic sea ice system have cascading impacts on the biogeochemical cycles of the ocean. Sea ice transports sediments, nutrients, trace metals, pollutants, and gases from the extensive continental shelves into the more isolated central basins. However, it is difficult to assess the net contribution of this supply mechanism on nutrients in the surface ocean. In this study, we used Manganese (Mn), a micronutrient and tracer which can integrate source fluctuations in space and time, to understand the net impact of the long range transport of sea ice for Mn.</p><p>We developed a three-dimensional dissolved Mn model within a subdomain of the 1/12 degree Arctic and Northern Hemispheric Atlantic (ANHA12) configuration of NEMO centred on the Canadian Arctic Archipelago, and evaluated this model with in situ observations from the 2015 Canadian GEOTRACES cruises. The Mn model incorporates parameterizations for the contributions from river discharge, sediment resuspension, atmospheric deposition of aerosols directly to the ocean and via melt from sea ice, release of sediment from sea ice, and reversible scavenging, while the NEMO-TOP engine takes care of the advection and diffusion of the tracers. </p><p>Simulations with this model from 2002 to 2019 indicate that the majority of external Mn contributed annually to the Canada Basin surface is released by sediment from sea ice, much of which originates from the Siberian shelves. Reduced sea ice longevity in the Siberian shelf regions has been postulated to result in the disruption of the long range transport of sea ice by the transpolar drift. This reduced sea ice supply has the potential to decrease the Canada Basin Mn surface maximum and downstream Mn supply, with implications for other nutrients (such as Fe) contained in ice-rafted sediments as well. These results demonstrate some of the many changes to the biogeochemical supply mechanisms expected in the near-future in the Arctic Ocean and the subpolar seas.</p>

scholarly journals Pacific Water Transport in the Western Arctic Ocean Simulated by an Eddy-Resolving Coupled Sea Ice–Ocean Model

2009 ◽  
Vol 39 (9) ◽  
pp. 2194-2211 ◽  
Author(s):  
Eiji Watanabe ◽  
Hiroyasu Hasumi
Keyword(s):  
Sea Ice ◽  
Water Transport ◽  
Chukchi Sea ◽  
Mesoscale Eddy ◽  
Late Summer ◽  
Ocean Model ◽  
Canada Basin ◽  
Pacific Water ◽  
Freshwater Transport ◽  
The Pacific

Abstract The process of the Pacific water transport in the Chukchi Sea and the southern Canada Basin is investigated by using an eddy-resolving coupled sea ice–ocean model. The simulation result demonstrates that the Pacific water flows into the basin by mesoscale baroclinic eddies, which are generated and developed as a result of the instability of a narrow and intense jet through the Barrow Canyon. Each eddy has a baroclinic anticyclonic structure, and its horizontal and vertical scales grow up by being merged with other ones during August and September, they separate into anticyclones whose diameters are about 50 km in October, and then they gradually shrink in early winter. The Pacific water transport across the Beaufort shelf break reaches maximum (about 0.3 Sv, where 1 Sv ≡ 106 m3 s−1) during late summer and early autumn when the eddy activities are enhanced. The sensitivity experiments indicate that the shelf-to-basin transport differs depending on the sea ice condition in the Chukchi Sea during summer. The difference is found to be associated with the jet strength, which is closely related to the location of the sea ice margin. When the sea ice margin is located in the Canada Basin, the jet is stronger, and mesoscale eddy activities and corresponding inflow of the Pacific water into the basin are enhanced. When sea ice remains in the shelf even in late summer, sea ice ocean stress plays a great role in braking the jet and the consequent suppression of the shelf-to-basin transport. The freshwater and heat transports into the basin associated with the Pacific water inflow depend on not only the volume flux but also on surface buoyancy flux in the shelf, which varies according to sea ice condition. The freshwater transport referenced to 34.8 psu is 259 km3 yr−1 in the medium sea ice extent case. Although the Pacific water becomes freshened as a result of its mixing with sea ice meltwater in the large extent case, the freshwater transport is still less than in the other cases. The heat transport is promoted by preferable absorption of solar heat in addition to energetic eddy-induced transport in the small extent case. The heat amount provided into the basin is equivalent to the reduction of sea ice thickness by about 1 m yr−1 north of the Chukchi and Beaufort shelf breaks.

scholarly journals Thinner Sea Ice Contribution to the Remarkable Polynya Formation North of Greenland in August 2018

2021 ◽  
Author(s):  
Xiaoyi Shen ◽  
Chang-Qing Ke ◽  
Bin Cheng ◽  
Wentao Xia ◽  
Mengmeng Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Reanalysis Data ◽  
Mean Value ◽  
Ocean Model ◽  
North Coast ◽  
Average Value ◽  
The North ◽  
Wind Sea ◽  
The One

AbstractIn August 2018, a remarkable polynya was observed off the north coast of Greenland, a perennial ice zone where thick sea ice cover persists. In order to investigate the formation process of this polynya, satellite observations, a coupled ice-ocean model, ocean profiling data, and atmosphere reanalysis data were applied. We found that the thinnest sea ice cover in August since 1978 (mean value of 1.1 m, compared to the average value of 2.8 m during 1978–2017) and the modest southerly wind caused by a positive North Atlantic Oscillation (mean value of 0.82, compared to the climatological value of −0.02) were responsible for the formation and maintenance of this polynya. The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind. Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region.

scholarly journals Arctic Sea Ice Retreat in 2007 Follows Thinning Trend

2009 ◽  
Vol 22 (1) ◽  
pp. 165-176 ◽  
Author(s):  
R. W. Lindsay ◽  
J. Zhang ◽  
A. Schweiger ◽  
M. Steele ◽  
H. Stern
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Extent ◽  
Pacific Side ◽  
Arctic Sea ◽  
The Arctic Ocean

Abstract The minimum of Arctic sea ice extent in the summer of 2007 was unprecedented in the historical record. A coupled ice–ocean model is used to determine the state of the ice and ocean over the past 29 yr to investigate the causes of this ice extent minimum within a historical perspective. It is found that even though the 2007 ice extent was strongly anomalous, the loss in total ice mass was not. Rather, the 2007 ice mass loss is largely consistent with a steady decrease in ice thickness that began in 1987. Since then, the simulated mean September ice thickness within the Arctic Ocean has declined from 3.7 to 2.6 m at a rate of −0.57 m decade−1. Both the area coverage of thin ice at the beginning of the melt season and the total volume of ice lost in the summer have been steadily increasing. The combined impact of these two trends caused a large reduction in the September mean ice concentration in the Arctic Ocean. This created conditions during the summer of 2007 that allowed persistent winds to push the remaining ice from the Pacific side to the Atlantic side of the basin and more than usual into the Greenland Sea. This exposed large areas of open water, resulting in the record ice extent anomaly.

Ocean model formulation influences climate sensitivity

2021 ◽  
Author(s):  
Tido Semmler ◽  
Johann Jungclaus ◽  
Christopher Danek ◽  
Helge F Goessling ◽  
Nikolay Koldunov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Sensitivity ◽  
North Atlantic ◽  
Heat Content ◽  
Ocean Model ◽  
Max Planck ◽  
Coupled Models ◽  
Ocean Heat Uptake ◽  
Marine Research ◽  
Transient Climate Response

<p>The climate sensitivity is known to be mainly determined by the atmosphere model but here we discover that the ocean model can change a given transient climate response (TCR) by as much as 20% while the equilibrium climate sensitivity (ECS) change is limited to 10%. In our study, two different coupled CMIP6 models (MPI-ESM and AWI-CM) in two different resolutions each are compared. The coupled models share the same atmosphere-land component ECHAM6.3, which has been developed at the Max-Planck-Institute for Meteorology (MPI-M). However, as part of MPI-ESM and AWI-CM, ECHAM6.3 is coupled to two different ocean models, namely the MPIOM sea ice-ocean model developed at MPI-M and the FESOM sea ice-ocean model developed at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). A reason for the different TCR is different ocean heat uptake through greenhouse gas forcing in AWI simulations compared to MPI-M simulations. Specifically, AWI-CM simulations show stronger surface heating than MPI-ESM simulations while the MPI-M model accumulates more heat in the deeper ocean. The vertically integrated ocean heat content is increasing stronger in MPI-M model configurations compared to AWI model configurations in the high latitudes. Strong vertical mixing in MPI-M model configurations compared to AWI model configurations seems to be key for these differences. The strongest difference in vertical ocean mixing occurs inside the Weddell Gyre, but there are also important differences in another key region, the northern North Atlantic. Over the North Atlantic, these differences materialize in a lack of a warming hole in AWI model configurations and the presence of a warming hole in MPI-M model configurations. All these differences occur largely independent of the considered model resolutions.</p>

Observation of nitrate deficit along transects across the Canada Basin after major sea-ice loss

Polar Science ◽  
2019 ◽  
Vol 21 ◽  
pp. 224-227 ◽  
Author(s):  
Yanpei Zhuang ◽  
Hongliang Li ◽  
Haiyan Jin ◽  
Jianfang Chen ◽  
Shengquan Gao ◽  
...  
Keyword(s):  
Sea Ice ◽  
Canada Basin ◽  
Nitrate Deficit

scholarly journals Assimilating SMOS sea ice thickness into a coupled ice-ocean model using a local SEIK filter

2014 ◽  
Vol 119 (10) ◽  
pp. 6680-6692 ◽  
Author(s):  
Qinghua Yang ◽  
Svetlana N. Losa ◽  
Martin Losch ◽  
Xiangshan Tian-Kunze ◽  
Lars Nerger ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ocean Model ◽  
Ice Thickness ◽  
Sea Ice Thickness
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