Publication Date:
2017-04-04
Description:
The connection between Tropical Pacific and North Pacific variability is investigated in a state-of-the art coupled ocean-atmosphere model, comparing two 20th century simulations at T30 and T106 atmospheric horizontal resolutions. Despite a better simulation of the frequency and the spatial distribution of the Tropical Pacific anomalies associated with the El Nino Southern Oscillation (ENSO) in the high-resolution experiment, the response in the North Pacific is scarcely different from the low-resolution experiment where the ENSO variability is weaker and at higher than
observed frequency. In the North Pacific, the response of surface atmospheric fields to the variability in the Tropical
Pacific appears to be affected by local coupling processes significantly different in the two experiments. The coupling
between sea level pressure (SLP) and sea surface temperature (SST) in the North Pacific as well as the influence of the
Tropical Pacific SST has been measured here by means of the ‘coupled manifold’ technique. In the low-resolution case
the SLP variances linked to the fraction of North Pacific SST not influenced by the Tropical Pacific are weak suggesting
that the remote influence is strong, consistently with the observations. On the contrary, in the high-resolution experiment
the fractions and the patterns of the SLP variances due to the Tropical Pacific SST and those linked to the North Pacific
SST are comparable. In the latter case, model systematic errors in the northwestern Pacific influences the local coupling
processes thus triggering the remote response. We conclude that an increased atmospheric horizontal resolution does not
reduce the coupled model systematic errors in the representation of the teleconnection between the North and the Tropical
Pacific and that the validation of coupled models has to consider both remote and local processes.
Description:
Published
Description:
1640-1653
Description:
3.7. Dinamica del clima e dell'oceano
Description:
JCR Journal
Description:
open
Keywords:
Tropical Pacific-North Pacific teleconnection
;
ENSO
;
coupled GCMs
;
01. Atmosphere::01.01. Atmosphere::01.01.02. Climate
;
01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics
;
03. Hydrosphere::03.01. General::03.01.03. Global climate models
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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