A numerical study of open water formation in sea ice

Haapala, Jari; Lönnroth, Nadja Teresia; Stössel, Achim

doi:10.1029/2003jc002200

Cited by 55 publications

(46 citation statements)

References 42 publications

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“…The relevance of the BASIS-ice data set (and our easier-to-access derivative), however, goes beyond that: as the Arctic sea ice declines and waterways such as the Northwest Passage become more navigable, the need for sea ice nowcasts and forecasts is increasing. This relates not only to ice concentration and thickness but also to the modelling of ice properties, and in particular ridged ice (such as Funkvist and Kleine, 2007;Haapala, 2000;Haapala et al, 2005), because ridges are difficult to break and thus form substantial obstacles for ships. Also, the presence of ridged or deformed ice bears witness to preceding large ice stresses which can lead to a substantial slowdown and, in the worst case, even cause damage to ships (see, e.g.…”

Section: Discussionmentioning

confidence: 99%

Sea ice in the Baltic Sea – revisiting BASIS ice, a historical data set covering the period 1960/1961–1978/1979

Löptien

Dietze

2014

Earth Syst. Sci. Data

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Abstract. The Baltic Sea is a seasonally ice-covered, marginal sea in central northern Europe. It is an essential waterway connecting highly industrialised countries. Because ship traffic is intermittently hindered by sea ice, the local weather services have been monitoring sea ice conditions for decades. In the present study we revisit a historical monitoring data set, covering the winters 1960/1961 to 1978/1979. This data set, dubbed Data Bank for Baltic Sea Ice and Sea Surface Temperatures (BASIS) ice, is based on hand-drawn maps that were collected and then digitised in 1981 in a joint project of the Finnish Institute of Marine Research (today the Finnish Meteorological Institute (FMI)) and the Swedish Meteorological and Hydrological Institute (SMHI). BASIS ice was designed for storage on punch cards and all ice information is encoded by five digits. This makes the data hard to access. Here we present a post-processed product based on the original five-digit code. Specifically, we convert to standard ice quantities (including information on ice types), which we distribute in the current and free Network Common Data Format (NetCDF). Our post-processed data set will help to assess numerical ice models and provide easy-to-access unique historical reference material for sea ice in the Baltic Sea. In addition we provide statistics showcasing the data quality. The website www.baltic-ocean.org hosts the post-processed data and the conversion code.

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Section: Discussionmentioning

confidence: 99%

Sea ice in the Baltic Sea – revisiting BASIS ice, a historical data set covering the period 1960/1961–1978/1979

Löptien

Dietze

2014

Earth Syst. Sci. Data

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“…The cyclone impact on sea ice has been investigated in numerous model studies using, among others, different approaches for the atmospheric forcing. For example, Haapala et al (2005) prescribe a moving artificial cyclone, Kawaguchi and Mitsudera (2008) prescribe a stationary artificial cyclone, and Kriegsmann and Brümmer (2013) use the pressure field of the operational ECMWF (European Centre of Medium-Range Weather forecast) analysis. Common to all model approaches is that they come up with a decrease of ice concentration of a similar order of magnitude as found here, that is, in a range of −0.5 to −2 % per 24 h. The magnitude of the deformation shows less clear variation during the cyclone passage.…”

Section: Impact Of Synoptic Systems: Cyclones and Anticyclonesmentioning

confidence: 99%

Atmosphere–ice forcing in the transpolar drift stream: results from the DAMOCLES ice-buoy campaigns 2007–2009

Haller¹,

Brümmer²,

Müller³

2014

The Cryosphere

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Abstract. During the EU research project Developing Arctic Modelling and Observing Capabilities for Long-term Environmental Studies (DAMOCLES), 18 ice buoys were deployed in the region of the Arctic transpolar drift (TPD). Sixteen of them formed a quadratic grid with 400 km side length. The measurements lasted from 2007 to 2009. The properties of the TPD and the impact of synoptic weather systems on the ice drift are analysed. Within the TPD, the speed increases by a factor of almost three from the North Pole to the Fram Strait region. The hourly buoy position fixes would show that the speed is underestimated by 10-20 % if positions were taken at only 1-3 day intervals as it is usually done for satellite drift estimates. The geostrophic wind factor U i / U g (i.e. the ratio of ice speed U i and geostrophic wind speed U g ), in the TPD amounts to 0.012 on average, but with regional and seasonal differences. The constant U i / U g relation breaks down for U g < 5 m s −1 . The impact of synoptic weather systems is studied applying a composite method. Cyclones (anticyclones) cause cyclonic (anticyclonic) vorticity and divergence (convergence) of the ice drift. The amplitudes are twice as large for cyclones as for anticyclones. The divergence caused by cyclones corresponds to a 0.1-0.5 % per 6 h open water area increase based on the composite averages, but reached almost 4 % within one day during a strong August 2007 storm. This storm also caused a long-lasting (over several weeks) rise of U i and U i / U g and changed the ice conditions in a way which allowed large amplitudes of inertial ice motion. The consequences of an increasing Arctic storm activity for the ice cover are discussed.

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“…Although new sea-ice models with explicitly resolved sea-ice categories for ridged and rafted ice (Haapala et al 2005) have been applied in scenario simulations for the Baltic Sea, results for ice categories are not yet published.…”

Section: Sea Icementioning

confidence: 99%

Projected Change—Marine Physics

Meier

2015

Regional Climate Studies

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This chapter assesses recent results of changes in water temperature, salinity, sea ice, storm surges and wind waves during the twenty-first century in scenario simulations for the Baltic Sea. There have been several improvements since the first Baltic Sea assessment of climate change: the number of relevant scenario simulations has increased, ensembles of transient simulations with improved models based upon the scenarios and global models of IPCC's Fourth Assessment Report (AR4) have been analysed, and changes in biogeochemical cycles are now considered. The scenario simulations project that water temperatures will increase in the future, with the greatest changes in the northern Baltic Sea during summer. In agreement with earlier studies, sea-ice cover is projected to decrease drastically. Salinity is projected to decrease due to increased river run-off, whereas the impact of wind changes on salinity is negligible because the latter is relatively small. However, uncertainty in salinity projections is large owing to considerable bias in the simulated water balance. According to one study, salt transport into the Baltic Sea is unchanged. Sea-level rise has greater potential to increase surge levels in the Baltic Sea than increased wind speed, and changes in wind waves are projected to be small.

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A numerical study of open water formation in sea ice

Cited by 55 publications

References 42 publications

Sea ice in the Baltic Sea – revisiting BASIS ice, a historical data set covering the period 1960/1961–1978/1979

Sea ice in the Baltic Sea – revisiting BASIS ice, a historical data set covering the period 1960/1961–1978/1979

Atmosphere–ice forcing in the transpolar drift stream: results from the DAMOCLES ice-buoy campaigns 2007–2009

Projected Change—Marine Physics

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