Dynamic–Thermodynamic Sea Ice Model: Ridging and Its Application to Climate Study and Navigation

2005 ◽  
Vol 18 (18) ◽  
pp. 3840-3855 ◽  
Author(s):  
Sergey V. Shoutilin ◽  
Alexander P. Makshtas ◽  
Motoyoshi Ikeda ◽  
Alexey V. Marchenko ◽  
Roman V. Bekryaev
Keyword(s):  
Sea Ice ◽  
Arctic Basin ◽  
Circulation Pattern ◽  
Ice Cover ◽  
The Arctic ◽  
Partial Recovery ◽  
Pacific Side ◽  
Pattern Production ◽  
Ice Model

Abstract A dynamic–thermodynamic sea ice model with the ocean mixed layer forced by atmospheric data is used to investigate spatial and long-term variability of the sea ice cover in the Arctic basin. The model satisfactorily reproduces the averaged main characteristics of the sea ice and its extent in the Arctic Basin, as well as its decrease in the early 1990s. Employment of the average ridge shape for describing the ridging allows the authors to suggest that it occurs in winter and varies from year to year by a factor of 2, depending on an atmospheric circulation pattern. Production and horizontal movement of ridges are the focus in this paper, as they show the importance of interannual variability of the Arctic ice cover. The observed thinning in the 1990s is a result of reduction in ridge formation on the Pacific side during the cyclonic phase of the Arctic Oscillation. The model yields a partial recovery of sea ice cover in the last few years of the twentieth century. In addition to the sea ice cover and average thickness compared with satellite data, the ridge amount is verified with observations taken in the vicinity of the Russian coast. The model results are useful to estimate long-term variability of the probability of ridge-free navigation in different parts of the Arctic Ocean, including the Northern Sea Route area.

The Robustness of Midlatitude Weather Pattern Changes due to Arctic Sea Ice Loss

2016 ◽  
Vol 29 (21) ◽  
pp. 7831-7849 ◽  
Author(s):  
Hans W. Chen ◽  
Fuqing Zhang ◽  
Richard B. Alley
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Coupled System ◽  
Circulation Pattern ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Intrinsic Variability ◽  
Arctic Sea ◽  
Arctic Sea Ice Loss

Abstract The significance and robustness of the link between Arctic sea ice loss and changes in midlatitude weather patterns is investigated through a series of model simulations from the Community Atmosphere Model, version 5.3, with systematically perturbed sea ice cover in the Arctic. Using a large ensemble of 10 sea ice scenarios and 550 simulations, it is found that prescribed Arctic sea ice anomalies produce statistically significant changes for certain metrics of the midlatitude circulation but not for others. Furthermore, the significant midlatitude circulation changes do not scale linearly with the sea ice anomalies and are not present in all scenarios, indicating that the remote atmospheric response to reduced Arctic sea ice can be statistically significant under certain conditions but is generally nonrobust. Shifts in the Northern Hemisphere polar jet stream and changes in the meridional extent of upper-level large-scale waves due to the sea ice perturbations are generally small and not clearly distinguished from intrinsic variability. Reduced Arctic sea ice may favor a circulation pattern that resembles the negative phase of the Arctic Oscillation and may increase the risk of cold outbreaks in eastern Asia by almost 50%, but this response is found in only half of the scenarios with negative sea ice anomalies. In eastern North America the frequency of extreme cold events decreases almost linearly with decreasing sea ice cover. This study’s finding of frequent significant anomalies without a robust linear response suggests interactions between variability and persistence in the coupled system, which may contribute to the lack of convergence among studies of Arctic influences on midlatitude circulation.

scholarly journals Impact of a Reduced Arctic Sea Ice Cover on Ocean and Atmospheric Properties

2012 ◽  
Vol 25 (1) ◽  
pp. 307-319 ◽  
Author(s):  
Jan Sedláček ◽  
Reto Knutti ◽  
Olivia Martius ◽  
Urs Beyerle
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Arctic Basin ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Storm Tracks ◽  
The Arctic ◽  
The North ◽  
Arctic Sea ◽  
The North Atlantic

Abstract The Arctic sea ice cover declined over the last few decades and reached a record minimum in 2007, with a slight recovery thereafter. Inspired by this the authors investigate the response of atmospheric and oceanic properties to a 1-yr period of reduced sea ice cover. Two ensembles of equilibrium and transient simulations are produced with the Community Climate System Model. A sea ice change is induced through an albedo change of 1 yr. The sea ice area and thickness recover in both ensembles after 3 and 5 yr, respectively. The sea ice anomaly leads to changes in ocean temperature and salinity to a depth of about 200 m in the Arctic Basin. Further, the salinity and temperature changes in the surface layer trigger a “Great Salinity Anomaly” in the North Atlantic that takes roughly 8 yr to travel across the North Atlantic back to high latitudes. In the atmosphere the changes induced by the sea ice anomaly do not last as long as in the ocean. The response in the transient and equilibrium simulations, while similar overall, differs in specific regional and temporal details. The surface air temperature increases over the Arctic Basin and the anomaly extends through the whole atmospheric column, changing the geopotential height fields and thus the storm tracks. The patterns of warming and thus the position of the geopotential height changes vary in the two ensembles. While the equilibrium simulation shifts the storm tracks to the south over the eastern North Atlantic and Europe, the transient simulation shifts the storm tracks south over the western North Atlantic and North America. The authors propose that the overall reduction in sea ice cover is important for producing ocean anomalies; however, for atmospheric anomalies the regional location of the sea ice anomalies is more important. While observed trends in Arctic sea ice are large and exceed those simulated by comprehensive climate models, there is little evidence based on this particular model that the seasonal loss of sea ice (e.g., as occurred in 2007) would constitute a threshold after which the Arctic would exhibit nonlinear, irreversible, or strongly accelerated sea ice loss. Caution should be exerted when extrapolating short-term trends to future sea ice behavior.

scholarly journals Phytoplankton distribution in unusually low sea ice cover over the Pacific Arctic

2012 ◽  
Vol 9 (2) ◽  
pp. 2055-2093 ◽  
Author(s):  
P. Coupel ◽  
H. Y. Jin ◽  
M. Joo ◽  
R. Horner ◽  
H. A. Bouvet ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Basin ◽  
Ice Cover ◽  
The Arctic ◽  
In Situ Data ◽  
Phytoplankton Distribution ◽  
The Pacific ◽  
Phytoplankton Communities ◽  
Ice Retreat ◽  
The Impact

Abstract. A large part of the Pacific Arctic basin experiences ice-free conditions in summer as a result of sea ice cover steadily decreasing over the last decades. To evaluate the impact of ice retreat on the Arctic ecosystem, we investigated phytoplankton communities from coastal sites (Chukchi shelf) to northern deep basins (up to 86° N), during year 2008 of high melting. Pigment and taxonomy in situ data were acquired under different ice regime: the ice -free basins (IFB, 74°–77° N), the marginal ice zone (MIZ, 77°–80° N) and the heavy ice covered basins (HIB, >80° N). Our results suggest that extensive ice melting provided favorable conditions to chrysophytes and prymnesiophytes growth and more hinospitable to pico-sized prasinophytes and micro-sized dinoflagellates. Larger cell diatoms were less abundant in the IFB while dominant in the MIZ of the deep Canadian basin. Our data were compared to those obtained during more icy years, 1994 and to a lesser extent, 2002. Freshening, stratification, light and nutrient availability are discussed as possible causes for observed phytoplankton communities under high and low sea ice cover.

Investigating the interactions among river flow, salinity and sea ice using a global coupled atmosphere—ocean—ice model

1997 ◽  
Vol 25 ◽  
pp. 121-126 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Sea Ice ◽  
River Discharge ◽  
River Flow ◽  
Ice Cover ◽  
The Arctic ◽  
Fram Strait ◽  
Ice Flow ◽  
Basin Scale ◽  
Flow Through ◽  
Ice Model

A global coupled atmosphere-ocean-ice model is used to examine the interdependence among several components of the hydrologic cycle in the Arctic Ocean, including river discharge, sea-ice cover, and the flow of sea ice through Fram Strait. Since the ocean model has a free surface, fresh-water inflow from rivers is added directly to the ocean. The timing of the peak spring river flow depends on snowmelt runoff and its subsequent routing through the river system. Thermodynamic sea ice is included, and a new sea-iee advection scheme is described. The model’s river discharge affects salinity at the mouth of large rivers. The effect of the river discharge on sea-ice cover is not clear, either locally or at the basin scale. There is significant inter-annual variability of ice flow through Fram Strait, but the model’s flow is about half of that observed. The anomalous ice flow through Fram Strait is most highly correlated with the meridional wind stress. Potential implications for the “great salinity” anomaly are discussed.

scholarly journals Investigating the interactions among river flow, salinity and sea ice using a global coupled atmosphere—ocean—ice model

1997 ◽  
Vol 25 ◽  
pp. 121-126 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Sea Ice ◽  
River Discharge ◽  
River Flow ◽  
Ice Cover ◽  
The Arctic ◽  
Fram Strait ◽  
Ice Flow ◽  
Basin Scale ◽  
Flow Through ◽  
Ice Model

A global coupled atmosphere-ocean-ice model is used to examine the interdependence among several components of the hydrologic cycle in the Arctic Ocean, including river discharge, sea-ice cover, and the flow of sea ice through Fram Strait. Since the ocean model has a free surface, fresh-water inflow from rivers is added directly to the ocean. The timing of the peak spring river flow depends on snowmelt runoff and its subsequent routing through the river system. Thermodynamic sea ice is included, and a new sea-iee advection scheme is described. The model’s river discharge affects salinity at the mouth of large rivers. The effect of the river discharge on sea-ice cover is not clear, either locally or at the basin scale. There is significant inter-annual variability of ice flow through Fram Strait, but the model’s flow is about half of that observed. The anomalous ice flow through Fram Strait is most highly correlated with the meridional wind stress. Potential implications for the “great salinity” anomaly are discussed.

scholarly journals Fram Strait sea ice export variability and September Arctic sea ice extent over the last 80 years

2016 ◽  
Author(s):  
Lars H. Smedsrud ◽  
Mari H. Halvorsen ◽  
Julienne C. Stroeve ◽  
Rong Zhang ◽  
Kjell Kloster
Keyword(s):  
Sea Ice ◽  
Arctic Basin ◽  
Recent Decade ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Fram Strait ◽  
Sea Ice Extent ◽  
Arctic Sea ◽  
Arctic Sea Ice Extent

Abstract. The Arctic Basin exports between 600,000 and 1 million km2 of it's sea ice cover southwards through Fram Strait each year, or about 10 % of the sea-ice covered area inside the basin. During winter, ice export results in growth of new and relatively thin ice inside the basin, while during summer or spring, export contributes directly to open water further north that enhances the ice-albedo feedback during summer. A new updated time series from 1935 to 2014 of Fram Strait sea ice area export shows that the long-term annual mean export is about 880,000 km2, with large inter-annual and multidecadal variability, and no long-term trend over the past 80 years. Nevertheless, the last decade has witnessed increased ice export, with several years having annual ice export that exceed 1 million km2. Evaluating the trend onwards from 1979, when satellite based sea ice coverage became more readily available, reveals an increase in annual export of about +6 % per decade. The observed increase is caused by higher southward ice drift speeds due to stronger southward geostrophic winds, largely explained by increasing surface pressure over Greenland. Spring and summer area export increased more (+11 % per decade) than in autumn and winter (+2.6 % per decade). Contrary to the last decade, the 1950–1970 period had relatively low export during spring and summer, and consistently mid-September sea ice extent was higher during these decades than both before and afterwards. We thus find that export anomalies during spring have a clear influence on the following September sea ice extent in general, and that for the recent decade, the export may be partially responsible for the accelerating decline in Arctic sea ice extent.

scholarly journals The Recent Decline of the Arctic Summer Sea-Ice Cover in the Context of Internal Climate Variability

2008 ◽  
Vol 2 (1) ◽  
pp. 91-100 ◽  
Author(s):  
W. Dorn ◽  
K. Dethloff ◽  
A. Rinke ◽  
M. Kurgansky
Keyword(s):  
Climate Variability ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Interannual Variability ◽  
Arctic Basin ◽  
Ice Cover ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Internal Climate Variability ◽  
Arctic Summer

By means of a 21-year simulation of a coupled regional pan-Arctic atmosphere-ocean-ice model for the 1980's and 1990's and comparison of the model results with SSM/I satellite-derived sea-ice concentrations, the patterns of maximum amplitude of interannual variability of the Arctic summer sea-ice cover are revealed. They are shown to concentrate beyond an area enclosed by an isopleth of barotropic planetary potential vorticity that marks the edge of the cyclonic rim current around the deep inner Arctic basin. It is argued that the propagation of the interannual variability signal farther into the inner Arctic basin is hindered by the dynamic isolation of upper Arctic Ocean and the high summer cloudiness usually appearing in the central Arctic. The thinning of the Arctic sea-ice cover in recent years is likely to be jointly responsible for its exceptionally strong decrease in summer 2007 when sea-ice decline was favored by anomalously high atmospheric pressure over the western Arctic Ocean, which can be regarded as a typical feature for years with low sea-ice extent. In addition, unusually low cloud cover appeared in summer 2007, which led to substantial warming of the upper ocean. It is hypothesized that the coincidence of several favorable factors for low sea-ice extent is responsible for this extreme event. Owing to the important role of internal climate variability in the recent decline of sea ice, a temporal return to previous conditions or stabilization at the current level can not be excluded just as further decline.

scholarly journals Modeling Linear Kinematic Features in Sea Ice

2005 ◽  
Vol 133 (12) ◽  
pp. 3481-3497 ◽  
Author(s):  
Jennifer K. Hutchings ◽  
Petra Heil ◽  
William D. Hibler
Keyword(s):  
Sea Ice ◽  
Wind Stress ◽  
Spatial Scales ◽  
Arctic Basin ◽  
The Arctic ◽  
Pack Ice ◽  
Embedded Model ◽  
Failure Propagation ◽  
Ice Strength ◽  
Ice Model

Abstract Sea ice deformation is localized in narrow zones of high strain rate that extend hundreds of kilometers, for example, across the Arctic Basin. This paper demonstrates that these failure zones may be modeled with a viscous–plastic sea ice model, using an isotropic rheology. If the ice is assumed to be heterogeneous at the grid scale, and allowed to weaken in time, intersecting failure zones propagate across the region. The direction of failure propagation depends upon the stress applied to the ice (wind stress and boundary conditions) and the rheological model describing plastic failure of the ice. The spacing between failure zones is controlled by the magnitude of the wind stress and the distribution describing spatial variability of ice strength. Sea ice motion and deformation oscillate at close to a 12-h period throughout the Arctic and Antarctic pack ice. This oscillation is found at all spatial scales from hundreds of kilometers to the lead scale. It is shown that with an inertial embedded model, sea ice deformation rotates between pairs of fault patterns with a semidiurnal period. It is well known that linear zones of deformation exist at many spatial scales throughout the Arctic Basin. The model presented in this paper may be scaled to simulate these features.

scholarly journals Arctic sea-ice oscillation: regional and seasonal perspectives

2001 ◽  
Vol 33 ◽  
pp. 481-492 ◽  
Author(s):  
Jia Wang ◽  
Moto Ikeda
Keyword(s):  
Sea Ice ◽  
Decadal Variability ◽  
Phase Fluctuation ◽  
Reduction Rate ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Empirical Orthogonal Functions ◽  
The Arctic ◽  
Arctic Sea

AbstractVariability of the sea-ice cover (extent) in the Northern Hemisphere (Arctic and subpolar regions) associated with the Arctic Oscillation (AO) is investigated using historical data from 1901 to 1997. A principal-component analysis (empirical orthogonal functions (EOFs)) was applied to sea-ice area (SIA) anomalies for the period 1953−95. The leading EOF mode for the SI A anomaly shows an in-phase fluctuation in response to the AO and is called the Arctic sea-ice oscillation (ASIO). Arctic sea ice experiences seasonal variations that differ in timing and magnitude. Four types of seasonal variation are identified in the Arctic sea ice, and are superimposed on long-term interannual to decadal variability. Consistent with the total Arctic SIA anomaly eight regional SIA anomalies have shown significant in-phase decrease (downward trend) since 1970, possibly part of a very long-term (century) cycle. Thus, it is recommended that SIA anomalies in the sensitive seasons be used to better capture interannual, interdecadal and longer (century) variability. Major decadal and interdecadal time-scales of SIA anomalies are found at 12−14 and 17−20 years. In the Sea of Okhotsk, a century time-scale is evident. The reduction rate (negative trend) of the total Arctic sea-ice cover in the last three decades is −4.5% per decade, with the summer rate being the highest (-10.2% per decade). The contribution to this total reduction varies from region to region, with sea-ice cover in the Greenland and Norwegian Seas experiencing the highest reduction rate of −20.2 % per decade.

Sign in / Sign up

Export Citation Format

Share Document