Constarium
← Search

Data · dataset · 2026

On the dynamical mechanisms governing El Niño–Southern Oscillation irregularity

Listed in National Center for Atmospheric Research

This study investigates the mechanisms by which short time-scale perturbations to atmospheric processes can affect El Nino-Southern Oscillation (ENSO) in climate models.

Description

To this end a control simulation of NCAR's Community Climate System Model is compared to a simulation in which the model's atmospheric diabatic tendencies are perturbed every time step using a Stochastically Perturbed Parameterized Tendencies (SPPT) scheme.

The SPPT simulation compares better with ECMWF's twentieth-century reanalysis in having lower interannual sea surface temperature (SST) variability and more irregular transitions between El Nino and La Nina states, as expressed by a broader, less peaked spectrum. Reduced-order linear inverse models (LIMs) derived from the 1-month lag covariances of selected tropical variables yield good representations of tropical interannual variability in the two simulations.

Read the rest (2 more)

In particular, the basic features of ENSO are captured by the LIM's least damped oscillatory eigenmode. SPPT reduces the damping time scale of this eigenmode from 17 to 11 months, which is in better agreement with the 8 months obtained from reanalyses. This noise-induced stabilization is consistent with perturbations to the frequency of the ENSO eigenmode and explains the broadening of the SST spectrum (i.e., the greater ENSO irregularity).

Although the improvement in ENSO shown here was achieved through stochastic physics parameterizations, it is possible that similar improvements could be realized through changes in deterministic parameterizations or higher numerical resolution. It is suggested that LIMs could provide useful insight into model sensitivities, uncertainties, and biases also in those cases.

Links

Get the data

Where it is published

Catalogue records · 1

Topics

Inferred from text
Atmospheric dynamics 76% · Simulation 75%
Provenance · 1 source records, 9 field assertions
SourceKeyLast seenRaw
National Center for Atmospheric Research3cd33f29-4ef7-4a4c-a522-2d6b24048f7611 d agoJSON v1
FieldAssertionExtractorEvidence
concepts[field].anzsrc:field:370105enrichment · data ucar edutaxonomy-embedding@1.1.0title+keywords+description (76%)
concepts[field].local:field:earth-environmentalmapping · data ucar educonnector:data_ucar_edu@1.0.0
concepts[field].local:field:ocean-atmosphericmapping · data ucar educonnector:data_ucar_edu@1.0.0
concepts[method].local:method:simulationenrichment · data ucar edukeyword-concept-rules@1.0.0title+description (75%)
created_datesource · data ucar educonnector:data_ucar_edu@1.0.0
descriptionsource · data ucar educonnector:data_ucar_edu@1.0.0/notes
publication_datesource · data ucar educonnector:data_ucar_edu@1.0.0
titlesource · data ucar educonnector:data_ucar_edu@1.0.0/title
updated_datesource · data ucar educonnector:data_ucar_edu@1.0.0