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| Titel |
Northern Hemisphere teleconnection patterns in ensemble simulation from 1500 to 2100: Stability and forcing impacts |
| VerfasserIn |
C. C. Raible, D. Hofer, T. F. Stocker |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023562
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| Zusammenfassung |
| The climate variability of the atmospheric circulation is characterized by a number of
preferred patterns, the so-called teleconnection patterns. These patterns, like the North
Atlantic Oscillation (NAO) or the Pacific North American (PNA) pattern, modulate the heat,
moisture and momentum fluxes, and influence the strength and the location of major
cyclone tracks. Studies show that not only the low-frequency variability connected to
teleconnections changes with time, but also the centers of action shift. Thus, there is
still a need to understand the low-frequency variability and the stability of these
teleconnections.
A detailed analysis is undertaken of teleconnection patterns of the Northern Hemisphere in an
ensemble of GCM simulations for the period 1500-2100 and a 1990 control simulation. Four
transient simulations are performed with the Community Climate System Model (version 3.0,
CCSM3), using time-varying greenhouse gas, solar, and volcanic forcing functions (and the
A2 scenario for 2000-2100).
The Northern Hemisphere teleconnection patterns defined by teleconnectivity of the
1000-hPa and 500-hPa geopotential height show that the locations of the centers of action are
not stable in time. For the period 1500-2000 the ensemble simulations show no clear
connection to natural and anthropogenic forcing functions suggesting that the instability of
teleconnection patterns and their low-frequency behavior is dominated by internal
atmosphere-ocean dynamics. |
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