This second edition of a much lauded work, unique on this topic in the english language, has. Pdf key findings the decline in arctic summer sea ice extent has accelerated over the past ten years. Due to the recently observed acceleration in sea ice drift, it has been assumed that more matter is advected by the transpolar drift from shallow shelf waters to the central arctic ocean and beyond. This study presents sea ice drift measurements that were made from a research vessel within the marginal ice zone miz of the fall beaufort sea.
Relationships between arctic sea ice drift and strength. The science of sea ice drift through its 100year history to the present day is explained. The drift of sea ice pdf by matti lepparanta part of the springer praxis books series. Jul 22, 2020 when sea ice drift is turned on, the respective stellar flux threshold is 3550 and 12501276 w m. Scaling aspects of the seaicedrift dynamics and pack fracture. The shoreline was developed from envisat and radarsat imagery from october 2009 until april 2010.
The forecasting of ice drift and pressure has to be carried out on a scale relevant to shipping and. Schweiger 1and jinlun zhang 1polar science center, applied physics laboratory, university of washington, seattle, washington, usa abstract arctic sea ice drift forecasts of 6 h9 days for the summer of 2014 are generated using the mar. Overview of nrc sea ice and iceberg forecasting and. Therefore, it is necessary to mask the land and islands before monitoring the sea ice drift. Characterization of seaice kinematic in the arctic outflow.
Nilas, pancake, and ice raft photographs courtesy don perovich, cold regions research and. An analytical model for winddriven arctic summer sea ice drift. We showed in the section estimation of the wind and ocean drifts that the sea ice drift observed at the mooring sites was reproduced well by the combination of oceanic drift from the numerical model and wind drift from the geostrophic wind with f 0. Following a description of the modeled mean sea ice drift, thickness and growth, the simulated sea ice drift is compared to the tracks of three sea ice buoys. Holland1and ron kwok2 the sea ice cover around antarctica has experienced a slight expansion in area over the past decades1,2. This is not particularly surprising as sea ice drift responds within a few hours to atmospheric wind forcing. In addition, satellite data indicate that average sea ice transit times in recent years. For the purposes of the sheba drift, the rgps team at jpl created a special data set consisting of ice motion ona5km grid, 200 200 km in extent, and centered on the sheba. Drift ice ryuhyo in japanese is the name for sea ice that is moved by winds and currents. The ao can modulate the orientation of tds, and consequently the sea ice export into fram strait vihma etal. The second edition of the drift of sea ice presents the fundamental laws of sea. Observed antarctic sea ice expansion reproduced in a climate model after correcting biases in sea ice drift velocity. In the ice covered part of the arctic ocean the circulation of the surface water has been deduced from sea ice drift. Atmospheric forcing on the drift of arctic sea ice in 1989.
Arctic sea ice drift measured by shipboard marine radar faculty. Ice growth on sea surface and drift of ice encyclopedia of life. Abstract results of an earlier study suggest that sea ice drift in climate. View and compare sea ice extent data for any year or any combination of years between 1979 and 2014 including nearrealtime daily data. The conventional mask method for land and island is to manually extract the coastline from satellite images. Variability of sea ice cover in the chukchi sea western. The main sink of ice from the arctic ocean is through fram strait. The nps institutional archive theses and dissertations thesis collection 1964 a computer program for forecasting the wind drift of sea ice. It presents the fundamental laws of sea ice drift which come from the material properties of sea ice and the basic laws of mechanics. Vis ir mw sea ice topography roughness sea ice concentration roughness drift ice sheet margin topography motion continent ice shelf. The ross sea region, including three main polynya areas in mcmurdo sound, terra nova bay, and in front of the.
Over time, large sheets of ice collide, forming thick pressure ridges along the margins 4 th image. Pdf the topic of sea ice is once again in the pages of nautology. Unlike fast ice, which is fastened to a fixed object, drift ice is carried along by winds and sea currents, hence its name. To identify the source and destination of sea ice in this region can help to thoroughly understand the mass exchange of sea ice between the systems of bg and tds, which may further influence sea ice loss in the. Current studies attempt to derive the ice drift from the ssmi data field. Pdf variations in the age of arctic seaice and summer. Hemisphere sea ice cover provide a first impression of largescale sea ice dynamics.
Thus, the sea conditions and climatic situations in cooler seasons are very favorable for the ice formation and the ice drift in the western half of the okhotsk sea which are very striking as will be mentioned in. Amsreaqua daily l3 100 km sea ice drift polar grids algorithm updated to. Visualize sea ice extent data for the arctic and more recently, the antarctic. Ssmi data, sea ice observations and ocean measurements from the nathaniel b. This recent change in the chukchi sea ice could be the result of reduced sea ice production on this shelf, more summer ice melting, because of warmer surface waters. Drift ice, also called brash ice, is sea ice that is not attached to the shoreline or any other fixed object shoals, grounded icebergs, etc. The largescale pattern of sea ice drift over the full time period is similar in both products. The arctic climate and the sea ice drift are important to study both for the. When drift ice is driven together into a large single mass 70% coverage, it is called pack ice. This raises the question as to whether the satellitederived sea ice drift. Many sources influence water movement including tides, bathymetry and wind. The ted sea ice model has eight categories each for ice thickness, ice enthalpy, and snow depth. Regression analysis of winter sea ice drift in the southern. The effect of the mean geostrophic upperocean currents on the average circulation of sea ice pack is known to be as important as the mean.
Figure 4a shows the average drift pattern and velocity of arctic sea ice. Time variability in the annual cycle of sea ice thickness in. Seasonal and interannual variability of the arctic sea ice. Arctic warming interrupts the transpolar drift and affects. The sea ice model is a thickness and enthalpy distribution ted sea ice model zhang and rothrock, 2001. The nic shapefile is the newest ice shelf definition, completed by nic science department in june 2011. The resulting system of equations is analysed for the general properties of sea ice drift, the free drift model and analytical models for ice drift in the presence of internal friction, and the construction of numerical ice drift models is detailed. This means that sea ice drift increases the snowball onset threshold by. Aug 01, 2014 evaluation of southward drift of sea ice. Satellite observations for detecting and forecasting seaice. The drift of 52 icebergs tagged with gps buoys in the weddell sea since 1999 has been investigated with respect to prevalent drift tracks, sea ice iceberg interaction, and freshwater fluxes. The second edition of the drift of sea ice presents the fundamental laws of sea ice drift which come from the material properties of sea ice and the basic laws of mechanics.
Longterm analysis of sea ice drift in the western ross sea. Effect of seaice drift on the onset of snowball climate on. Extraction of drift direction of sea ice is equivalent to drawing the drift trajectory of sea ice. An animation of the combined expression of the dynamic and thermodynamic processesthe drift of the ice and its seasonal. Thus, sea ice drift provides an excellent test bed for. Drift and differential drift scaling the momentum balance of sea ice may be written dv m. Largescale drift of arctic sea ice retrieved from passive. Impact of temporalspatio resolution on sea ice drift and deformation.
After establishing a new camp on 21 august 2020 fig. Atmospheric forcing on the drift of arctic sea ice in 19892009. Ice drift and deformation seem particularly sensitive to the forcing caused by topographic change, as enhanced by ocean currents. It became known that sea ice drifts over long distances, and nansen 1902 found, in his fram expedition in 189396 across the eurasian side of the arctic ocean. As a result, sea ice strength has been reduced, allowing more deformation and fracturing and leading to increased sea ice drift speed. It is first shown that the arctic sea ice velocity field can be objectively decomposed into a mean field and fluctuations. A computer program for forecasting the wind drift of sea ice. The apparently sluggish thin ice in models ice suggests that trends in arctic sea ice export fram strait might be underestimated. The centers of the eight ice thickness categories are 0, 0. Topics covered include the science of sea ice drift, forecasting drift velocity based on volume, size and shape, sea ice ridging and remote sensing. Nov 11, 2012 winddriven trends in antarctic seaice drift paul r.
This paper provides an overview of the arctic sea ice history spanning multiple climate regimes, from the early cenozoic to present. Sea ice begins as thin sheets of smooth nilas in calm water top or disks of pancake ice in choppy water 2 nd image. The study found that broadscale ice drift patterns observed by buoys can be reproduced by satellitederived data but also that ice motion velocities from satellites are too low heil and others, 2001. Some sea ice holds fast to a coastline or the sea floorfast ice while pack ice drifts with winds and currents. Drift ice was still visible around sakhalin and hokkaido on the last day of winter, when the moderate resolution imaging spectroradiometer modis on nasas terra satellite acquired the third image. In the current issue, the phenomenon of ice drift on marine waters has been. Apparent sea ice drift issues in cmip3 rampal et al cmip3 models have unrealistic ice drift speeds, seasonal cycle and trends. On timescales longer than a year the contributions from the winds and ocean currents in driving sim are roughly equal, but as shown in fig. An analytical model for winddriven arctic summer sea ice. In addition, satellite data indicate that average sea ice transit times in recent years are shorter than in the 1980s e. Extraction of drift direction and speed of sea ice of the. Individual pieces pile up to form rafts and eventually solidify 3 rd image.
The drift of sea ice across the isobars in these longterm means fig. The prominent spring bloom and its relation to sea. Estimates of the surface heat budget over drifting ice and open water in the arctic ocean are made using eddy correlation and fluxprofile methods using data obtained from drifting ice and from. First the drift ice material is presented ending with the concept of ice state the relevant properties in sea ice dynamics. Was this bias a source of reduced sea ice thinning and loss in cmip3. The drift of sea ice brings together for the first time in one volume the theory, observations and practical applications of research into sea ice drift. Get daily sea ice extent values by rolling your cursor over a line in the graph. This small overall increase is the sum of much larger opposing trends in different sectors that have been proposed to result from changes in. The thinning of arctic sea ice ohio state university. Reassessing the role of sea ice drift in arctic sea ice loss. Observed and modelled seaice drift response to wind forcing in the.
The study area was a transition zone between openwater and the icecovered ocean in the northern baltic sea. Palmer giulivi and jacobs, 1997 to validate ice extent, thickness and water mass characteristics. The wind dependence of seaice motion was studied on the basis of ice velocity and wind observations, and weather model output. Observed antarctic sea ice expansion reproduced in a. Time variability in the annual cycle of sea ice thickness. Results 9 our model shows that by september 2002 the area of old ice decreased dramatically and most of the arctic ocean was covered by ice less than 5 years old figure 2b. The term pack ice is used either as a synonym to drift ice, or to designate drift ice zone in which the floes are densely packed. Sea ice kinematics and surface properties from radarsat. Ice kinematics observations are widely presented with the mathematical analysis methods, and thereafter come drift ice rheology to close the triangle material kinematics stress. The arctic low resolution sea ice drift products provided from ifremer have a. The highpressure cell above the beaufort sea creates an anticyclonic gyre that feeds the transpolar drift, crossing the lomonosov ridge from the canadian to the eurasian. These processes are highly interrelated because the fracture events occur due to interaction between ice.
Reassessing sea ice drift and its relationship to long. The text includes the geophysical theory, observations from field programs, and mathematical models. The resulting system of equations is analysed for the general properties of sea ice drift, the free drift model and. Leadsnarrow, linear openings ranging in size from meters to kilometerscontinually form and disappear. Because pack ice is dynamic, pieces can collide and form much thicker ice. Characterization of seaice kinematic in the arctic. The result will be an ice drift deflected 5 to 15 to the right in the northern hemisphere. Sea ice cover and ice drift patterns 4 in the arctic ocean, sea ice formation occurs largely over the shallow continental shelves surrounding the basin, notably in the east siberian and laptev seas, where the shelf is wide and the surface salinity is particularly low. In this chapter, sea ice drift is discussed in terms of statistical properties of individual lagrangian trajectories. Sea ice cover and thickness have substantially decreased in the arctic ocean since the beginning of the satellite era. Effect of seaice drift on the onset of snowball climate. The gf4 remote sensing satellite images, which are used to monitor sea ice drift, include land, sea and sea. In this study, we show that sea ice drift in modern climate models is more. The author presents in the drift of sea ice the fundamental laws of sea ice drift which come from the material properties of sea ice and the basic laws of mechanics.
In the sea of okhotsk, 30 profiling floats have been deployed since 1997 ohshima et al. All these deficiencies make the estimate of the arctic sea ice thickness and drift variations all year round difficult with only satellite sea ice data. Ice extent, thickness, drift, and duration arctic sea ice cover attains its maximum seasonal extent in. Pdf the paper presents results of research based on analysis of historical and present studies of the arctic ice drift. Backward and forward drift trajectories of sea ice in the. A comparison of satellitederived seaice motion with. The resulting system of equations is analysed for the general properties of sea ice drift, the free drift model and analytical models for ice drift in the presence of internal friction, and the construction of numerical ice drift. The drift of sea ice matti lepparanta, matti lepparanta. What drives the southward drift of sea ice in the sea of. Variations in the age of arctic seaice and summer seaice extent. Forecasting the drift of pack ice and ice pressure buildup, predicting the risk of a vessel besetting, and quantifying ice pressure conditions are all essential for safe and efficient operations in northern waters.
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