Effect of land albedo, CO2, orography, and oceanic heat transport on extreme climates


Contact
lohmann [ at ] awi-bremerhaven.de

Abstract

Using an atmospheric general circulation model of intermediate complexity coupled to a sea ice - slab ocean model, we perform a number of sensitivity experiments under present-day orbital conditions and geographical distributionto assess the possibility that land albedo, atmospheric CO2, orography and oceanic heat transport may cause an icecovered Earth. Changing only one boundary or initial condition, the model produces solutions with at least some icefree oceans in the low latitudes. Using some combination of these forcing parameters, a full Earth's glaciation is obtained. We find that the most significant factor leading to anice-covered Earth is the high land albedo in combination with initial temperatures set equal to the freezing point. Oceanic heat transport and orography play only a minor role for theclimate state. Extremely low concentrations of CO2 also appearto be insufficient to provoke a runaway ice-albedo feedback, but the strong deviations in surface air temperatures in the Northern Hemisphere point to the existence of a strong nonlinearity in the system. Finally, we argue that the initial condition determines whether the system can go into a completely ice covered state, indicating multiple equilibria, a feature known from simple energy balance models.



Item Type
Article
Authors
Divisions
Programs
Publication Status
Published
Eprint ID
14075
Cite as
Romanova, V. , Lohmann, G. and Grosfeld, K. (2006): Effect of land albedo, CO2, orography, and oceanic heat transport on extreme climates , Climate of the Past, 2. {www.clim-past.net/2/31/2006/}, 31 .


Download
[thumbnail of Fulltext]
Preview
PDF (Fulltext)
Rom2005e.pdf

Download (6MB) | Preview
Cite this document as:

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email

Research Platforms
N/A

Campaigns
N/A


Actions
Edit Item Edit Item