Modelling the mass balance and salinity of Arctic and Antarctic sea ice

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Presses univ. de Louvain, 2008 - 220 pages
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Ice formed from seawater, called sea ice, is both an important actor in and a sensitive indicator of climate change. Covering 7% of the World Ocean, sea ice damps the atmosphere-ocean exchanges of heat, radiation and momentum in polar regions. It also affects the oceanic circulation at a global scale. Recent satellite and submarine observations systems indicate a sharp decrease in the extent and volume of Arctic sea ice over the last 30 years. In addition, climate models project drastic sea ice reductions for the next century, in both hemispheres, with potentially large consequences on climate and ecosystems.

Contrary to what is commonly believed, sea ice retains about 25% of the oceanic salt when it forms. As salt cannot lock in the ice crystalline lattice, it accumulates in liquid inclusions of salty water (brine). Under a temperature change, the inclusions freeze or melt and release or absorb huge amounts of latent heat. This affects heat transfer through and storage in sea ice, which may affect the mass balance of sea ice at a global scale. This is the central hypothesis of this work.

In order to address this problem, the author develops two sea ice models and assesses their ability to simulate the recent evolution of the sea ice mass balance. Then, the physics of brine uptake and drainage are included in the models and sea ice desalination is investigated. Finally, the impact of sea ice salinity variations on the global sea ice mass balance is studied. The roles of sea ice thermal properties, of ice-ocean salt / fresh water fluxes and of oceanic feedbacks are evaluated. The new salinity module improves the simulation of ice and ocean characteristics compared to observations. Including salinity variations increases ice growth, reduces vertical mixing in the ocean and the ocean-to-ice heat flux. In conclusion, salinity variations should be included in future sea ice models used for climate projections.

 

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Table des matières

Modelling the mass balance and salinity of Arctic and Antarctic
1
Sea ice halothermodynamics in LIM1D
35
On the sensitivity of undeformed Arctic sea ice to its vertical salinity
43
mod
53
Modeling the salinity pro le of undeformed Arctic sea ice VFB06
97
Simulating the mass balance and salinity of Arctic and Antarctic
109
Simulating the mass balance and salinity of Arctic and Antarctic
155
Conclusion
193
Bibliography
199

Expressions et termes fréquents

À propos de l'auteur (2008)

Born in Tournai in July 1980, Martin Vancoppenolle joined the Facultés de Namur in 1998 and then the Université catholique de Louvain in 2000 (UCL, Louvain-la-Neuve), where he completed a Master Degree in Physics of Climate in 2003. Under the supervision of Professor Thierry Fichefet, he started a Ph.D at the Institut G. Lemaître (UCL), that he completed in 2008. Martin attended numerous scientific meetings abroad, took part into two field campaigns in both the Arctic and Antarctic regions

Informations bibliographiques