A Thermodynamic Model of the Formation, Growth, and Decay of First-Year Sea Ice

AbstractThe formulation and application of a onedimensional sea-ice thermodynamic model is presented in this paper. The model’s sensitivity to changes in oceanic and atmospheric parameters is analyzed and compared with previous studies. The model is next applied to three locations in the Arctic: Cambridge Bay, Frobisher Bay, and Alert Inlet to study the model’s ability to simulate the annual cycle of first-year ice. The model’s results are compared with available climatological data and discussed in terms of the main thermodynamic processes, the combined effects of oceanic tides, and of sea-ice deterioration by melting on the break-up of sea ice.It is shown that the model is effective in simulating the climatology of the first-year ice thickness at the three Arctic locations. The study also suggests that improved model performance can be expected from additional research and application of flexural forcing of the ice by waves and tides, and of deterioration of ice strength during the melting process.

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Anomalous blocking over Greenland preceded the 2013 extreme early melt of local sea ice

Annals of Glaciology ◽

10.1017/aog.2017.30 ◽

2017 ◽

Vol 59 (76pt2) ◽

pp. 181-190 ◽

Cited By ~ 5

Author(s):

Thomas J. Ballinger ◽

Edward Hanna ◽

Richard J. Hall ◽

Thomas E. Cropper ◽

Jeffrey Miller ◽

...

Keyword(s):

Sea Ice ◽

North Atlantic ◽

Regional Climate ◽

Regional Climate Change ◽

Circulation Pattern ◽

The Arctic ◽

Labrador Sea ◽

First Year ◽

Tropospheric Circulation ◽

Blocking Index

ABSTRACTThe Arctic marine environment is undergoing a transition from thick multi-year to first-year sea-ice cover with coincident lengthening of the melt season. Such changes are evident in the Baffin Bay-Davis Strait-Labrador Sea (BDL) region where melt onset has occurred ~8 days decade−1 earlier from 1979 to 2015. A series of anomalously early events has occurred since the mid-1990s, overlapping a period of increased upper-air ridging across Greenland and the northwestern North Atlantic. We investigate an extreme early melt event observed in spring 2013. (~6σ below the 1981–2010 melt climatology), with respect to preceding sub-seasonal mid-tropospheric circulation conditions as described by a daily Greenland Blocking Index (GBI). The 40-days prior to the 2013 BDL melt onset are characterized by a persistent, strong 500 hPa anticyclone over the region (GBI >+1 on >75% of days). This circulation pattern advected warm air from northeastern Canada and the northwestern Atlantic poleward onto the thin, first-year sea ice and caused melt ~50 days earlier than normal. The episodic increase in the ridging atmospheric pattern near western Greenland as in 2013, exemplified by large positive GBI values, is an important recent process impacting the atmospheric circulation over a North Atlantic cryosphere undergoing accelerated regional climate change.

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Net community production in the bottom of first-year sea ice over the Arctic spring bloom

Geophysical Research Letters ◽

10.1002/2017gl074602 ◽

2017 ◽

Vol 44 (17) ◽

pp. 8971-8978 ◽

Cited By ~ 8

Author(s):

K. Campbell ◽

C. J. Mundy ◽

M. Gosselin ◽

J. C. Landy ◽

A. Delaforge ◽

...

Keyword(s):

Sea Ice ◽

Spring Bloom ◽

The Arctic ◽

First Year ◽

Net Community Production ◽

Community Production

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Distribution and Driving Mechanism of N2O in Sea Ice and Its Underlying Seawater during Arctic Melt Season

Water ◽

10.3390/w14020145 ◽

2022 ◽

Vol 14 (2) ◽

pp. 145

Author(s):

Jian Liu ◽

Liyang Zhan ◽

Qingkai Wang ◽

Man Wu ◽

Wangwang Ye ◽

...

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Ice Core ◽

The Arctic ◽

First Year ◽

Driving Mechanism ◽

Biogeochemical Processes ◽

Ice Melting ◽

Detailed Mechanism ◽

The Arctic Ocean

Nitrous oxide (N2O) is the third most important greenhouse gas in the atmosphere, and the ocean is an important source of N2O. As the Arctic Ocean is strongly affected by global warming, rapid ice melting can have a significant impact on the N2O pattern in the Arctic environment. To better understand this impact, N2O concentration in ice core and underlying seawater (USW) was measured during the seventh Chinese National Arctic Research Expedition (CHINARE2016). The results showed that the average N2O concentration in first-year ice (FYI) was 4.5 ± 1.0 nmol kg−1, and that in multi-year ice (MYI) was 4.8 ± 1.9 nmol kg−1. Under the influence of exchange among atmosphere-sea ice-seawater systems, brine dynamics and possible N2O generation processes at the bottom of sea ice, the FYI showed higher N2O concentrations at the bottom and surface, while lower N2O concentrations were seen inside sea ice. Due to the melting of sea ice and biogeochemical processes, USW presented as the sink of N2O, and the saturation varied from 47.2% to 102.2%. However, the observed N2O concentrations in USW were higher than that of T-N2OUSW due to the sea–air exchange, diffusion process, possible N2O generation mechanism, and the influence of precipitation, and a more detailed mechanism is needed to understand this process in the Arctic Ocean.

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Sea ice melt pond fraction estimation from dual-polarisation C-band SAR – Part 2: Scaling in situ to Radarsat-2

The Cryosphere Discussions ◽

10.5194/tcd-8-845-2014 ◽

2014 ◽

Vol 8 (1) ◽

pp. 845-885 ◽

Cited By ~ 1

Author(s):

R. K. Scharien ◽

K. Hochheim ◽

J. Landy ◽

D. G. Barber

Keyword(s):

Sea Ice ◽

Large Scale ◽

Temporal Frequency ◽

Model Performance ◽

Free Water ◽

Light Transmittance ◽

The Arctic ◽

Ice Melt ◽

Melt Pond

Abstract. Observed changes in the Arctic have motivated efforts to understand and model its components as an integrated and adaptive system at increasingly finer scales. Sea ice melt pond fraction, an important summer sea ice component affecting surface albedo and light transmittance across the ocean-sea ice–atmosphere interface, is inadequately parameterized in models due to a lack of large scale observations. In this paper, results from a multi-scale remote sensing program dedicated to the retrieval of pond fraction from satellite C-band synthetic aperture radar (SAR) are detailed. The study was conducted on first-year sea (FY) ice in the Canadian Arctic Archipelago during the summer melt period in June 2012. Approaches to retrieve the subscale FY ice pond fraction from mixed pixels in RADARSAT-2 imagery, using in situ, surface scattering theory, and image data are assessed. Each algorithm exploits the dominant effect of high dielectric free-water ponds on the VV/HH polarisation ratio (PR) at moderate to high incidence angles (about 40° and above). Algorithms are applied to four images corresponding to discrete stages of the seasonal pond evolutionary cycle, and model performance is assessed using coincident pond fraction measurements from partitioned aerial photos. A RMSE of 0.07, across a pond fraction range of 0.10 to 0.70, is achieved during intermediate and late seasonal stages. Weak model performance is attributed to wet snow (pond formation) and synoptically driven pond freezing events (all stages), though PR has utility for identification of these events when considered in time series context. Results demonstrate the potential of wide-swath, dual-polarisation, SAR for large-scale observations of pond fraction with temporal frequency suitable for process-scale studies and improvements to model parameterizations.

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A Moored Arctic Floater in First-Year Sea Ice Ridges

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4028814 ◽

2015 ◽

Vol 137 (1) ◽

Cited By ~ 2

Author(s):

Oddgeir Dalane ◽

Vegard Aksnes ◽

Sveinung Løset

Keyword(s):

Sea Ice ◽

Cross Sectional Area ◽

The Arctic ◽

First Year ◽

Sectional Area ◽

Cross Sectional ◽

Ridge Structure ◽

Structure Interaction ◽

Ship Model ◽

Mooring Forces

First-year sea ice ridges are a major concern for structures operating in the Arctic offshore and will in many cases give the design mooring load. In this paper, the response of a moored conical floater, somewhat similar to the well-known Kulluk, is studied in first-year ridges. The study is based on model tests performed at Hamburg Ship Model Basin (HSVA) in several ridges with different properties. Mooring forces and floater response, resulting from interaction with different ridges, were compared with respect to ridge properties, ridge behavior, and simulated ice management. Clearance of accumulated rubble upstream the structure was the dominating physical process in the ridge–structure interaction. Accumulation of rubble caused large mooring forces. The amount of accumulated rubble depended on the ridge cross-sectional area, thus the mooring forces increased with ridge cross-sectional area. Large mooring forces were also experienced after the ridge was passed by the structure due to difficulties with clearing of accumulated rubble.

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Tensile fracture of a single crack in first-year sea ice

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2017.0346 ◽

2018 ◽

Vol 376 (2129) ◽

pp. 20170346 ◽

Cited By ~ 8

Author(s):

J. P. Dempsey ◽

D. M. Cole ◽

S. Wang

Keyword(s):

Sea Ice ◽

Field Trips ◽

Cohesive Crack ◽

The Arctic ◽

Tensile Fracture ◽

First Year ◽

Crack Model ◽

Separation Curve ◽

Ice Phenomena

The break-up of sea ice in the Arctic and Antarctic has been studied during three field trips in the spring of 1993 at Resolute, NWT, and the fall of 2001 and 2004 on McMurdo Sound via in situ cyclic loading and fracture experiments. In this paper, the back-calculated fracture information necessary to the specification of an accurate viscoelastic fictitious (cohesive) crack model is presented. In particular, the changing shape of the stress separation curve with varying conditions and loading scenarios is revealed. This article is part of the theme issue ‘Modelling of sea-ice phenomena’.

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High-resolution ocean/sea ice/ice shelf simulation of the 79° North Glacier and Zachariae Isstrøm

10.5194/egusphere-egu21-15695 ◽

2021 ◽

Author(s):

Claudia Wekerle ◽

Ralph Timmermann ◽

Qiang Wang ◽

Rebecca McPherson

Keyword(s):

Sea Ice ◽

Continental Shelf ◽

Model Performance ◽

Greenland Ice Sheet ◽

Atlantic Water ◽

Ocean Model ◽

The Arctic ◽

Ice Shelf ◽

Time Period ◽

Mesh Resolution

<p>The 79&#176; North Glacier (79NG) is the largest of the marine terminating glaciers fed by the&#160; Northeast Greenland Ice Stream (NEGIS), which drains around 15% of the Greenland ice sheet. The 79NG is one of the few Greenland glaciers with a floating ice tongue, and is strongly influenced by warm Atlantic Water originating from Fram Strait and carried towards it through a trough system on the Northeast Greenland continental shelf.</p><p>Considering the decrease in thickness of the 79NG and also of the neighboring Zachariae Isstr&#248;m (ZI), we aim to understand the processes that potentially lead to the decay of these glaciers. As a first step we present here an ocean-sea ice simulation which explicitly resolves the cavities of the 79NG and ZI glaciers, applying the Finite-Element Sea ice-Ocean Model (FESOM). We take advantage of the multi-resolution capability of FESOM and locally increase mesh resolution in the vicinity of the 79NG to 700 m. The Northeast Greenland continental shelf is resolved with 3 km, and the Arctic Ocean and Nordic Seas with 4.5 km. The simulation is conducted for the time period 1980 to 2018, using JRA-55 atmospheric reanalysis. Solid and liquid runoff from Greenland is taken from the Bamber et al. 2018 dataset. The flow of warm Atlantic water into the glacier and outflow of meltwater is compared to observational data from measurement campaigns. We further use current and hydrographic data from moorings deployed in Norske Trough to assess the model performance in carrying warm water towards the glacier. This simulation spanning several decades allows us to investigate recent changes in basal melt rates induced by oceanic processes, in particular warm Atlantic Water transport towards the glacier.</p>

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Variability scaling and consistency in airborne and satellite altimetry measurements of Arctic sea ice

The Cryosphere ◽

10.5194/tc-14-751-2020 ◽

2020 ◽

Vol 14 (2) ◽

pp. 751-767

Author(s):

Shiming Xu ◽

Lu Zhou ◽

Bin Wang

Keyword(s):

Remote Sensing ◽

Sea Ice ◽

Snow Depth ◽

Spatial Scales ◽

Ice Cover ◽

Arctic Sea Ice ◽

The Arctic ◽

First Year ◽

Noise Levels ◽

Wide Range

Abstract. Satellite and airborne remote sensing provide complementary capabilities for the observation of the sea ice cover. However, due to the differences in footprint sizes and noise levels of the measurement techniques, as well as sea ice's variability across scales, it is challenging to carry out inter-comparison or consistently study these observations. In this study we focus on the remote sensing of sea ice thickness parameters and carry out the following: (1) the analysis of variability and its statistical scaling for typical parameters and (2) the consistency study between airborne and satellite measurements. By using collocating data between Operation IceBridge and CryoSat-2 (CS-2) in the Arctic, we show that consistency exists between the variability in radar freeboard estimations, although CryoSat-2 has higher noise levels. Specifically, we notice that the noise levels vary among different CryoSat-2 products, and for the European Space Agency (ESA) CryoSat-2 freeboard product the noise levels are at about 14 and 20 cm for first-year ice (FYI) and multi-year ice (MYI), respectively. On the other hand, for Operation IceBridge and NASA's Ice, Cloud, and land Elevation Satellite (ICESat), it is shown that the variability in snow (or total) freeboard is quantitatively comparable despite more than a 5-year time difference between the two datasets. Furthermore, by using Operation IceBridge data, we also find widespread negative covariance between ice freeboard and snow depth, which only manifests on small spatial scales (40 m for first-year ice and about 80 to 120 m for multi-year ice). This statistical relationship highlights that the snow cover reduces the overall topography of the ice cover. Besides this, there is prevalent positive covariability between snow depth and snow freeboard across a wide range of spatial scales. The variability and consistency analysis calls for more process-oriented observations and modeling activities to elucidate key processes governing snow–ice interaction and sea ice variability on various spatial scales. The statistical results can also be utilized in improving both radar and laser altimetry as well as the validation of sea ice and snow prognostic models.

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Measurements on Air Porosity of Sea Ice

Annals of Glaciology ◽

10.1017/s0260305500005486 ◽

1983 ◽

Vol 4 ◽

pp. 204-208 ◽

Cited By ~ 12

Author(s):

Masayoshi Nakawo

Keyword(s):

Sea Ice ◽

Atmospheric Pressure ◽

Vertical Profile ◽

The Arctic ◽

First Year ◽

Saturation Ratio ◽

Air Content ◽

Bubble Pressure ◽

Density Values ◽

Good Agreement

The air content of sea ice can be measured directly by melting a sample and collecting the released air, provided the air saturation ratio in the meltwater is known. The saturation ratio was found experimentally to be a function of three parameters: the time after an ice sample was melted, the average bubble size, and the air porosity of the sample. Since the last parameter is the term to be determined, an iteration method was employed in calculations of porosity. The bubble pressure was assumed to be at one atmospheric pressure. The vertical profile of air porosity was thus obtained for first-year sea ice in the Arctic. The results were in good agreement with estimations of porosity made from density values measured for the same samples. This indicates that the bubble pressure is near one atmospheric pressure.

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