 |
| Titel |
Effect of land albedo, CO2, orography, and oceanic heat transport on extreme climates |
| VerfasserIn |
V. Romanova, G. Lohmann, K. Grosfeld |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 2, no. 1 ; Nr. 2, no. 1 (2006-06-30), S.31-42 |
| Datensatznummer |
250000386
|
| Publikation (Nr.) |
 copernicus.org/cp-2-31-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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 distribution to assess the possibility that land albedo,
atmospheric CO2, orography and oceanic heat transport may cause an ice-covered Earth. Changing only one boundary or initial condition, the
model produces solutions with at least some ice-free 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 an ice-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 the
climate state. Extremely low concentrations of CO2 also appear to 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|