Mass Balance
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Mass Balance |
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| The Arctic sea ice
cover plays a major role in governing the exchange of energy between the
ocean and atmosphere in the polar regions. Changes in the thickness and
extent of the Arctic sea ice cover may be harbingers of climate change.
Results of global climate change models indicate that there is still much to
be learned about the details of the complex atmosphere-ice-ocean
interaction. Key to improving this understanding is the collection of field
measurements pertinent to the development of physically based
parameterizations of sea ice thermodynamic processes. A basic element in
studies focused on thermodynamics is the mass balance of the ice cover. The
ice mass balance is the great thermodynamic
integrator. If there is net warming over time, then there will be thinning
of the ice. Conversely, net cooling leads to thicker ice. Coupled with ice
temperature measurements, mass balance measurements provide valuable
information on the heat exchange among the air, ice and ocean. |
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| Making direct measurements of
the mass balance is simple. An array of stakes and
thickness gauges is used to measure ablation and accumulation of ice and
snow at the top and bottom of the ice cover (see right). In spite of the
importance of mass balance measurements and the relatively simple equipment
involved in making them, there are few observational results. This is due,
in large part, to the expense involved in operating a long-term field camp
to serve as the base for these studies.
The mass balance of sea ice can also be inferred autonomously using temperature profile measurements and acoustic position sensors. This project will supplement the exisiting mass balance database with observations from autonomous buoys. These mass balance buoys use thermistors to measure the ice temperature and acoustic sensor to determine the postion of the ice surface and bottom. Results from these autonomous mass balance buoys are presented in this web site. |
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Pressure ridge, pre-melt, April 1998 |
Pressure ridge, post-melt, August 1998 |
