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| Titel |
Transient teleconnection event at the onset of a planet-encircling dust storm on Mars |
| VerfasserIn |
O. Martínez-Alvarado, L. Montabone, S. R. Lewis, I. M. Moroz, P. L. Read |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 9 ; Nr. 27, no. 9 (2009-09-30), S.3663-3676 |
| Datensatznummer |
250016659
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3663-2009.pdf |
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| Zusammenfassung |
| We use proper orthogonal decomposition (POD)
to study a transient teleconnection event at the onset of
the 2001 planet-encircling dust storm on Mars,
in terms of empirical orthogonal functions (EOFs).
There are several differences between this and previous studies of
atmospheric events using EOFs.
First, instead of using a single variable such as surface pressure
or geopotential height on a given pressure surface, we
use a dataset describing the evolution in time of
global and fully three-dimensional
atmospheric fields
such as horizontal velocity and temperature.
These fields are produced by assimilating Thermal Emission Spectrometer
observations from NASA's Mars Global Surveyor spacecraft
into a Mars general circulation model.
We use total atmospheric energy (TE) as a physically
meaningful quantity which weights the state variables.
Second, instead of adopting the EOFs to define teleconnection
patterns as planetary-scale correlations that explain a large portion
of long time-scale variability,
we use EOFs to understand transient processes due to localised
heating perturbations that have
implications for the atmospheric circulation over distant regions.
The localised perturbation is given by anomalous heating due to the
enhanced presence of dust around the northern edge of
the Hellas Planitia basin on Mars.
We show that the localised disturbance is seemingly restricted
to a small number (a few tens) of EOFs.
These can be classified as low-order, transitional, or high-order EOFs
according to the TE amount they explain throughout the event.
Despite the global character of the EOFs,
they show the capability of accounting for the
localised effects of the perturbation
via the presence of specific centres of action.
We finally discuss possible applications for
the study of terrestrial phenomena with similar characteristics. |
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