Variability in Sea-Ice Thickness Over the North Pole from 1958 to 1992

AbstractArctic 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 m&#233;lange of thick ice and newly formed thin ice is present.

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

10.5194/os-2018-122 ◽

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.

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

10.4043/25572-ms ◽

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

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Arctic sea-ice morphological characteristics in summer 1996

Annals of Glaciology ◽

10.3189/172756401781818969 ◽

2001 ◽

Vol 33 ◽

pp. 165-170 ◽

Cited By ~ 12

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.

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

The Cryosphere ◽

10.5194/tc-12-3671-2018 ◽

2018 ◽

Vol 12 (11) ◽

pp. 3671-3691 ◽

Cited By ~ 16

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.

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Sea-ice model validation using submarine measurements of ice draft

Annals of Glaciology ◽

10.3189/172756400781820110 ◽

2000 ◽

Vol 31 ◽

pp. 307-312 ◽

Cited By ~ 1

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.

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Evaluation of sea-ice thickness reanalysis data from the coupled ocean-sea-ice data assimilation system TOPAZ4

Journal of Glaciology ◽

10.1017/jog.2020.110 ◽

2021 ◽

pp. 1-13

Author(s):

Yongwu Xiu ◽

Chao Min ◽

Jiping Xie ◽

Longjiang Mu ◽

Bo Han ◽

...

Keyword(s):

Sea Ice ◽

Reanalysis Data ◽

Ocean Modeling ◽

The Arctic ◽

Ice Thickness ◽

Coastal Zones ◽

Sea Ice Concentration ◽

Sea Ice Thickness ◽

Atlantic Sector ◽

The North

Abstract With the assimilation of satellite-based sea-ice thickness (SIT) data, the new SIT reanalysis from the Towards an Operational Prediction system for the North Atlantic European coastal Zones (TOPAZ4) was released from 2014 to 2018. Apart from assimilating sea-ice concentration and oceanic variables, TOPAZ4 further assimilates CS2SMOS SIT. In this study, the 5-year reanalysis is compared with CS2SMOS, the Pan-Arctic Ice-Ocean Modeling and Assimilating System (PIOMAS) and the Combined Model and Satellite Thickness (CMST). Moreover, we evaluate TOPAZ4 SIT with field observations from upward-looking sonar (ULS), ice mass-balance buoys, Operation IceBridge Quicklook and Sea State Ship-borne Observations. The results indicate TOPAZ4 well reproduces the spatial characteristics of the Arctic SIT distributions, with large differences with CS2SMOS/PIOMAS/CMST mainly restricted to the Atlantic Sector and to the month of September. TOPAZ4 shows thinner ice in March and April, especially to the north of the Canadian Arctic Archipelago with a mean bias of −0.30 m when compared to IceBridge. Besides, TOPAZ4 simulates thicker ice in the Beaufort Sea when compared to ULS, with a mean bias of 0.11 m all year round. The benefit from assimilating SIT data in TOPAZ4 is reflected in a 34% improvement in root mean square deviation.

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Real-time measurement of sea ice thickness, keel sizes and distributions and ice velocities using upward looking sonar instruments

OCEANS 2009 ◽

10.23919/oceans.2009.5422332 ◽

2009 ◽

Cited By ~ 1

Author(s):

David Fissel ◽

Rene Chave ◽

Jan Buermans

Keyword(s):

Sea Ice ◽

Real Time ◽

Time Measurement ◽

Ice Thickness ◽

Sea Ice Thickness ◽

Real Time Measurement

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In-situ automatic observations of ice thickness of seas

Metrology and Measurement Systems ◽

10.2478/v10178-012-0051-6 ◽

2012 ◽

Vol 19 (3) ◽

pp. 583-592 ◽

Cited By ~ 1

Author(s):

Yinke Dou ◽

Xiaomin Chang

Keyword(s):

Sea Ice ◽

New Technologies ◽

Capacitive Sensor ◽

Automatic Monitoring ◽

Ice Thickness ◽

In Situ Observation ◽

Glacier Surface ◽

Sea Ice Thickness ◽

Surface Ice

Abstract Ice thickness is one of the most critical physical indicators in the ice science and engineering. It is therefore very necessary to develop in-situ automatic observation technologies of ice thickness. This paper proposes the principle of three new technologies of in-situ automatic observations of sea ice thickness and provides the findings of laboratory applications. The results show that the in-situ observation accuracy of the monitor apparatus based on the Magnetostrictive Delay Line (MDL) principle can reach ±2 mm, which has solved the “bottleneck” problem of restricting the fine development of a sea ice thermodynamic model, and the resistance accuracy of monitor apparatus with temperature gradient can reach the centimeter level and research the ice and snow substance balance by automatically measuring the glacier surface ice and snow change. The measurement accuracy of the capacitive sensor for ice thickness can also reach ±4 mm and the capacitive sensor is of the potential for automatic monitoring the water level under the ice and the ice formation and development process in water. Such three new technologies can meet different needs of fixed-point ice thickness observation and realize the simultaneous measurement in order to accurately judge the ice thickness.

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