An intermediate one-dimensional thermodynamic sea ice model for investigating ice-atmosphere interactions

Journal Article · Tue Jun 15 04:00:00 EDT 1993 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/93JC00656· OSTI ID:86406

Ebert, E E ^[1]; Curry, J A ^[2]

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1. Bureau of Meteorology Research Centre, Melbourne (Australia)
2. Dept. of Aerospace Engineering Sciences, Boulder, CO (United States)

A one-dimensional thermodynamic model of sea ice is presented that focuses on those features that are most relevant to interactions with the atmosphere, namely the surface albedo and leads. It includes a surface albedo parameterization that interacts strongly with the state of the surface, and explicitly includes meltwater ponds. The lead parameterization contains a minimum lead fraction, absorption of solar radiation in and below the leads, predicting the current climatic sea ice conditions in the central Arctic when compared with observations and other theoretical calculations. The ice thickness was also quite sensitive to the meltwater runoff fraction and moderately sensitive to the other parameters in the melt pond parameterization, a result of the strong dependence of the surface albedo, and hence the net flux, on the surface conditions. To further investigate the physical interactions and internal feedback processes governing the sea ice-lead system, sensitivity tests were also performed for each of the external forcing variables. The model`s equilibrium sea ice thickness was extremely sensitive to changes in the downward longwave and shortwave fluxes and atmospheric temperature and humidity, moderately sensitive to the value of the ocean heat flux, and insensitive to values of wind speed, snowfall, and rainfall in the immediate vicinity of the baseline forcing. Four important positive feedback loops were identified and described: (1) the surface albedo feedback, (2) the conduction feedback, (3) the lead solar flux feedback, and (4) the lead fraction feedback. The destabilizing effects of these positive feedbacks were mitigated by two strong negative feedbacks: the outgoing longwave flux feedback, and the turbulent flux feedback. Considering the strong influence which sea ice has on global atmospheric and oceanic circulation patterns, it is essential that climate models be able to treat these feedback processes appropriately. 106 refs., 16 figs., 7 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 86406
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: C6 Vol. 98; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
COUPLING
CRYOSPHERE
EARTH ATMOSPHERE
ICE
ONE-DIMENSIONAL CALCULATIONS
SEAS
SIMULATION