The Seasonal Cycle of Sea Ice Thickness on the North East Greenland Shelf

2015 ◽  
Author(s):  
E. Hansen ◽  
S. Gerland ◽  
G. Spreen ◽  
K. Høyland
Keyword(s):  
Sea Ice ◽  
Seasonal Cycle ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
East Greenland ◽  
North East ◽  
The North

Sea Ice in the Greenland Polynya in 2018 - A Study with CryoSat-2 and SMOS

2020 ◽  
Author(s):  
Weixin Zhu ◽  
Lu Zhou ◽  
Shiming Xu
Keyword(s):  
Sea Ice ◽  
Global Climate ◽  
Arctic Sea Ice ◽  
Climate System ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
The North ◽  
Ice Surface ◽  
Snow Conditions

<p><strong>Abstract</strong></p><p>Arctic sea ice is a critical component in the global climate system. It affects the climate system by radiating incident heat back into space and regulating ocean-atmosphere heat and momentum. Satellite altimetry such as CryoSat-2 serves as the primary approach for observing sea ice thickness. Nevertheless, the thickness retrieval with CryoSat-2 mainly depends on the height of the ice surface above the sea level, which leads to significant uncertainties over thin ice regimes. The sea ice at the north of Greenland is considered one of the oldest and thickest in the Arctic. However, during late February - early March 2018, a polynya formed north to Greenland due to extra strong southern winds. We focus on the retrieval of sea ice thickness and snow conditions with CryoSat-2 and SMOS during the formation of the polynya. Specifically, we investigate the uncertainty of CryoSat-2 and carry out inter- comparison of sea ice thickness retrieval with SMOS and CryoSat-2/SMOS synergy. Besides, further discussion of retrieval with CryoSat-2 is provided for such scenarios where the mélange of thick ice and newly formed thin ice is present.</p>

scholarly journals Estimating Oceanic Heat Flux from Sea-Ice Thickness and Temperature Data

1990 ◽  
Vol 14 ◽  
pp. 315-318 ◽  
Author(s):  
J.S. Wettlaufer ◽  
N. Untersteiner ◽  
R. Colony
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Mass Balance ◽  
Temperature Data ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
North East ◽  
Oceanic Heat Flux ◽  
Ocean Models

All studies and models of air—sea-ice interactions suffer from a paucity of information about the oceanic heat flux, which exerts a controlling influence on the sea-ice energy and mass balance. The role of the oceanic heat flux in the sea-ice energy and mass balance is discussed. The performance of ice-ocean models depends on a satisfactory specification of this rarely measured oceanic parameter. A method for determining the oceanic heat flux by measuring the temperatures and thickness of sea ice is described. The results obtained using this method and the data collected during the fall of 1988 in the eastern Arctic are presented. Values of the oceanic heat flux ranging from 0 to 37 W m−2 were estimated from observations taken in the region north-east of Fram Strait. The oceanic heat flux in this region varied in both time and space.

scholarly journals Arctic sea ice drift-strength feedback modelled by NEMO-LIM3.6

2017 ◽  
Author(s):  
David Docquier ◽  
François Massonnet ◽  
Neil F. Tandon ◽  
Olivier Lecomte ◽  
Thierry Fichefet
Keyword(s):  
Sea Ice ◽  
Positive Feedback ◽  
Seasonal Cycle ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Drift Speed ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Ice Strength

Abstract. Sea ice cover and thickness have substantially decreased in the Arctic Ocean since the beginning of the satellite era. As a result, sea ice strength has been reduced, allowing more deformation and fracturing and leading to increased sea ice drift speed. The resulting increased sea ice export is thought to further lower sea ice concentration and thickness. We use the global ocean-sea ice NEMO-LIM3.6 model (Nucleus for European Modelling of the Ocean coupled to the Louvain-la-Neuve sea Ice Model), satellite and buoy observations, as well as reanalysis data over the period from 1979 to 2013 to study this positive feedback for the first time in such detail. Overall, the model agrees well with observations in terms of sea ice extent, concentration and thickness. Although the seasonal cycle of sea ice drift speed is reasonably well reproduced by the model, the recent positive trend in drift speed is weaker than observations in summer. NEMO-LIM3.6 is able to capture the relationships between sea ice drift speed, concentration and thickness in terms of seasonal cycle, with higher drift speed for both lower concentration and lower thickness, in agreement with observations. Sensitivity experiments are carried out by varying the initial ice strength and show that higher values of ice strength lead to lower sea ice thickness. We demonstrate that higher ice strength results in a more uniform sea ice thickness distribution, leading to lower heat conduction fluxes, which provide lower ice production, and thus lower ice thickness. This shows that the positive feedback between sea ice drift speed and strength is more than just dynamic, more complex than originally thought and that other processes are at play. The methodology proposed in this analysis provides a benchmark for a further model intercomparison related to the interactions between sea ice drift speed and strength.

scholarly journals Influence of initial stratification, wind and sea ice on the modelled oceanic circulation in Nares Strait, northwest Greenland

2018 ◽  
Author(s):  
Lovisa Waldrop Bergman ◽  
Céline Heuzé
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Global Climate ◽  
The Arctic ◽  
Ice Thickness ◽  
Oceanic Circulation ◽  
Regional Modelling ◽  
Sea Ice Thickness ◽  
Nares Strait ◽  
The North

Abstract. Nares Strait in northwest Greenland is one of the main gateways for oceanic freshwater and heat exchanges between the Arctic and the North Atlantic. With a changing Arctic climate, understanding the processes that govern the oceanic circulation in Arctic straits has become crucial and urgent, but this cannot be done with current geographically and temporally sparse in-situ observations only. High resolution regional modelling is thus required, but costly. We here report on one-year sensitivity experiments performed with the coupled ice-ocean regional model MITgcm to determine the relative importance of wind forcing, initial stratification and sea ice thickness on the accuracy of the modelled oceanic circulation in Nares Strait. We find that the modelled basin's circulation is mainly driven by density gradients in the upper oceanic layer, making accurate initial fields of temperature and salinity essential for a realistic oceanic circulation. The influence of the wind and sea ice thickness is less important, potentially making such high resolution fields not necessary for accurate strait modelling, provided these results are valid for other sea ice models as well. Comparison with ship-based measurements collected in summer 2015 reveals the experiments to be too cold at the surface, probably because of a not-dynamic-enough sea ice cover. Although the modelled freshwater is rather accurate, large efforts need to be put into observing the ocean and the sources of freshwater continuously throughout the year to produce realistic and efficient model simulations of the Arctic Straits, key players in the entire Arctic system and global climate.

scholarly journals Arctic sea-ice morphological characteristics in summer 1996

2001 ◽  
Vol 33 ◽  
pp. 165-170 ◽  
Author(s):  
P. Wadhams ◽  
N.R. Davis
Keyword(s):  
Sea Ice ◽  
Morphological Characteristics ◽  
Open Water ◽  
Arctic Sea Ice ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Thickness Profile ◽  
The North ◽  
Arctic Sea ◽  
Eurasian Basin

AbstractA sea-ice thickness profile obtained in September 1996 from the Greenland Sea and the Eurasian Basin, extending as far as the North Pole, has shown an unusually open ice cover with low mean drafts, large amounts of open water and little deep pressure ridging. Comparisons with data obtained from the same region in October 1976 show that mean ice draft has declined by 43% and that the decline can largely be ascribed to a loss of the thickest ice.

Variability in sea-ice thickness over the North Pole from 1977 to 1990

Nature ◽  
1992 ◽  
Vol 358 (6383) ◽  
pp. 224-226 ◽  
Author(s):  
A. S. McLaren ◽  
J. E. Walsh ◽  
R. H. Bourke ◽  
R. L. Weaver ◽  
W. Wrttmann
Keyword(s):  
Sea Ice ◽  
North Pole ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
The North

scholarly journals Impact of assimilating a merged sea-ice thickness from CryoSat-2 and SMOS in the Arctic reanalysis

2018 ◽  
Vol 12 (11) ◽  
pp. 3671-3691 ◽  
Author(s):  
Jiping Xie ◽  
François Counillon ◽  
Laurent Bertino
Keyword(s):  
Sea Ice ◽  
Degrees Of Freedom ◽  
The Arctic ◽  
Ice Thickness ◽  
Large Set ◽  
Sea Ice Thickness ◽  
The North ◽  
Ice Drift ◽  
Marine Environment Monitoring ◽  
The Impact

Abstract. Accurately forecasting the sea-ice thickness (SIT) in the Arctic is a major challenge. The new SIT product (referred to as CS2SMOS) merges measurements from the CryoSat-2 and SMOS satellites on a weekly basis during the winter. The impact of assimilating CS2SMOS data is tested for the TOPAZ4 system – the Arctic component of the Copernicus Marine Environment Monitoring Services (CMEMS). TOPAZ4 currently assimilates a large set of ocean and sea-ice observations with the Deterministic Ensemble Kalman Filter (DEnKF). Two parallel reanalyses are conducted without (Official run) and with (Test run) assimilation of CS2SMOS data from 19 March 2014 to 31 March 2015. Since only mapping errors were provided in the CS2SMOS observation, an arbitrary term was added to compensate for the missing errors, but was found a posteriori too large. The SIT bias (too thin) is reduced from 16 to 5 cm and the standard errors decrease from 53 to 38 cm (by 28 %) when compared to the assimilated SIT. When compared to independent SIT observations, the error reduction is 24 % against the ice mass balance (IMB) buoy 2013F and by 12.5 % against SIT data from the IceBridge campaigns. The improvement of sea-ice volume persists through the summer months in the absence of CS2SMOS data. Comparisons to sea-ice drift from the satellites show that dynamical adjustments reduce the drift errors around the North Pole by about 8 %–9 % in December 2014 and February 2015. Finally, using the degrees of freedom for signal (DFS), we find that CS2SMOS makes the prime source of information in the central Arctic and in the Kara Sea. We therefore recommend the assimilation of C2SMOS for Arctic reanalyses in order to improve the ice thickness and the ice drift.

scholarly journals Sea-ice model validation using submarine measurements of ice draft

2000 ◽  
Vol 31 ◽  
pp. 307-312 ◽  
Author(s):  
Timothy L. Shy ◽  
John E. Walsh ◽  
William L. Chapman ◽  
Amanda H. Lynch ◽  
David A. Bailey
Keyword(s):  
Sea Ice ◽  
Arctic Oscillation ◽  
The Arctic ◽  
Ice Thickness ◽  
Model Data ◽  
Sea Ice Thickness ◽  
The North ◽  
The Arctic Oscillation ◽  
Cavitating Fluid ◽  
Ice Model

AbstractSea-ice thickness distributions from 12 submarine cruises under the North Pole are used to evaluate and enhance the results of sea-ice model simulations. The sea-ice models include versions with cavitating fluid and elastic-viscous-plastic rheologies, and versions with a single thickness and with multiple (5–27) thicknesses in each gridcell. A greater portion of the interannual variance of observed mean thickness at the Pole is captured by the multiple-thickness models than by the single-thickness models, although even the highest correlations are only about 0.6. After The observed thickness distributions are used to ˚tune" the model to capture the primary mode of the distribution, the largest model-data discrepancies are in the thin-ice tail of the distribution. In a 41 year simulation ending in 1998, the model results show a pronounced decrease of mean ice thickness at the Pole around 1990; the minimum simulated thickness occurs in summer 1998. The decrease coincides with a shift of the Arctic Oscillation to its positive phase. The smallest submarine-derived mean thickness occurs in 1990, but no submarine data were available after 1992. The submarine-derived thicknesses for 1991 and 1992 are only slightly smaller than the 12–case mean.

scholarly journals Estimating Oceanic Heat Flux from Sea-Ice Thickness and Temperature Data

1990 ◽  
Vol 14 ◽  
pp. 315-318 ◽  
Author(s):  
J.S. Wettlaufer ◽  
N. Untersteiner ◽  
R. Colony
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Mass Balance ◽  
Temperature Data ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
North East ◽  
Oceanic Heat Flux ◽  
Ocean Models

All studies and models of air—sea-ice interactions suffer from a paucity of information about the oceanic heat flux, which exerts a controlling influence on the sea-ice energy and mass balance. The role of the oceanic heat flux in the sea-ice energy and mass balance is discussed. The performance of ice-ocean models depends on a satisfactory specification of this rarely measured oceanic parameter. A method for determining the oceanic heat flux by measuring the temperatures and thickness of sea ice is described. The results obtained using this method and the data collected during the fall of 1988 in the eastern Arctic are presented. Values of the oceanic heat flux ranging from 0 to 37 W m−2 were estimated from observations taken in the region north-east of Fram Strait. The oceanic heat flux in this region varied in both time and space.

Sign in / Sign up

Export Citation Format

Share Document