File formerly called: Breakout_session_sea_ice_MOSAiCPotsdam2013.doc
Breakout Session: sea ice
General remarks
unknown representativeness of single point snapshot measurements, PDF’s (spatial and temporal)
required, how to develop sub-grid scale parameterizations, difference between first and multi-year
ice
Large-scale modeling
Thermodynamics: spectral albedo and transmittance, snow cover (thickness, thermal conductivity,
snow water equivalent, snow-ice formation), ice ocean heat and salt exchange (ice melt at the
bottom, vertical and horizontal freezing and melting), surface and internal heat balance
Dynamics: momentum exchange, drag coefficient, cohesion and lead processes, ice rheology, ice
ocean wave interaction, contribution of tides, polar lows, baroclinic cyclones
Biogeochemistry: exchange of particles and gas with ocean and atmosphere (nutrients, carbon,…),
gas content and precipitated crystals in sea-ice and snow (ikaite, DIC, alkalinity,…)
Ecosystem: productivity and biomass (algae, food source,…), interaction biochemistry, physical
feedback (optics)
Large-scale observations: calibrate and develop improved retrieval algorithms for satellite data: seaice thickness and snow thickness, concentration, classification, melt ponds, drift vectors, floe size
distribution, albedo, heat fluxes
Process modeling
spectral albedo and transmittance:
1. limited knowledge for thin ice, optical properties of snow and ice (snow grain, impurities,
brine distribution, air bubbles); evolution, distribution and histograms of surface properties
(melt ponds, bare ice and snow), surface roughness, melt water pathways, frost flowers
2. later
3. energy balance of the couple system AOIL, heat storage in the ocean (memory of the
system), biology
4. crucial
5. later
snow cover:
1. limited knowledge or modeling capabilities of: precipitation rate, aging, redistribution (wind
drift), snow-ice interaction (brine fluxes, snow-ice formation), density distribution (freeboard
and melt ponds), thermal conductivity
2. later
3. strong impact on albedo and ice thickness evolution
4. crucial
5. later
ice ocean heat and salt exchange:
1. heat and salt balance at the ice ocean interface, turbulent and diffusive transport of heat and
salt in the water column, distribution of under ice roughness, floe size distribution (lateral vs.
vertical melt and freezing), salinity evolution of sea-ice
2. later
3. strong impact on water mass transformation and ocean dynamics
4. crucial
5. later
surface and internal heat balance:
1. limited knowledge and modeling capabilities of net long wave, short wave, heat and
humidity fluxes; heterogeneity of surface fluxes, direct measurements of fluxes, internal
phase changes, roughness, surface temperature, impacts of leads
2. later
3. controlling ice mass balance (freezing and melting, internal phase change)
4. crucial
5. later
momentum exchange:
1. limited knowledge and modeling capabilities: lack of measurements, direct measurements of
fluxes, lateral fluxes, roughness, form drag vs. surface drag, both with atmosphere and ocean
2. later
3. impact on baroclinic cyclones, large-scale ice dynamics
4. crucial
5. later
drag coefficient:
1. limited knowledge and modeling capabilities: ridging, snow redistribution, floe size
distribution, freeboard, surface inhomogeneities, open water distribution, under ice melt
ponds, under ice roughness, ice thickness distribution
2. later
3. essential for momentum exchange
4. crucial
5. later
cohesion and lead processes, ice rheology:
1. limited knowledge and modeling capabilities: evolution of cracks, impact on ice volume,
rafting, large-scale ice deformation, internal stress tensor, thermal expansion, ice break-up
2. later
3. essential for ice mass balance and dynamics
4. crucial
5. later
ice ocean wave interaction, contribution of tides:
1. limited knowledge and modeling capabilities: evolution of marginal sea-ice zone, wave
damping, ice break-up, ice floe interaction, impact on ice volume, sea-ice drift
2. later
3. essential for ice mass balance and dynamics and coastal erosion, internal stress tensor
4. crucial
5. later
polar lows, baroclinic cyclones:
1. limited knowledge and modeling capabilities: snow properties changes, ice break-up, iceatmosphere interaction, trigger for polar lows, importance for ice volume
2. later
3. essential for ice dynamics and volume, atmosphere ice feedbacks, cloud feedbacks
4. crucial
5. later
exchange of particles and gas with ocean and atmosphere:
1. limited knowledge and modeling capabilities: permeability of sea-ice, convectional exchange
of brine against sea water, carbon cycle and other biogeochemical cycles (methane,…),
impact of frost flowers
2. later
3. essential for global carbon budget, biological productivity and ecosystem functioning, ocean
acidification
4. crucial
5. later
gas content and precipitated crystals in sea-ice and snow:
1. limited knowledge and modeling capabilities: gas fraction of sea-ice, gas composition of seaice, distribution of solid crystals and nutrients, in-ice biogeochemistry
2. later
3. essential for permeability, global carbon budget, biological productivity and ecosystem
functioning, ocean acidification
4. crucial
5. later
Ecosystems:
1. limited knowledge and modeling capabilities: biomass evolution (limitations and triggers:
light, heat and nutrients), spring bloom, importance of water depth, impact on sea-ice
properties
2. later
3. essential for marine ecosystems
4. crucial
5. later
improved retrieval algorithms for satellite data:
1. fundamental lack of uncertainty estimates and error bars, essential requirement for high
quality retrieval algorithms and consistent time series, spatially resolved remote sensing of
fundamental sea-ice and snow properties for the entire Arctic
2. later
3. key for model evaluation, development of sub-grid parameterization for regional and largescale models, model initialization for predictability studies, Pan-Arctic sea-ice mass balance,
interannual and decadal scale variability
4. crucial
5. later