Chapter

Demystifying Climate Models

Volume 2 of the series Earth Systems Data and Models pp 87-108

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Date:

Simulating the Ocean and Sea Ice

  • Andrew GettelmanAffiliated withNational Center for Atmospheric Research Email author 
  • , Richard B. RoodAffiliated withAtmospheric, Oceanic and Space Sciences, College of Engineering, University of Michigan

Abstract

This chapter discusses ocean and sea-ice models. The ocean is a much larger reservoir of heat than the atmosphere. Therefore the heat content of the ocean is a critical part of the climate system. The ocean circulation is influenced by density, ocean boundaries (topography), the rotation of the earth and surface winds. The exchange of heat and water at the surface between the ocean and atmosphere is important for understanding the variability of the climate on time lengths of years to decades. Density plays an important role in the ocean: heavy water sinks; light water rises. The general nature of the ocean circulation cannot be understood without it. The density is related to temperature and salt, and the exchanges of heat and water with the atmosphere influence density. The cryosphere (“ice” sphere) contains land ice (ice sheets and glaciers), seasonal snow on land, and sea ice. Freezing and melting represent flows of energy between ice and atmosphere, land, and oceans. Models of sea ice are tightly coupled to the ocean. Sea ice is a critical part of the climate system because it strongly affects the reflection and absorption of solar energy (albedo). Sea ice also affects the surface energy coupling between the atmosphere and ocean. Thus, even though the cryosphere is a small area of the planet, it is an important part of the climate system, and it is critical at high latitudes. The role of the ocean and ice in sea-level rise projections is analyzed.