Identification

Title

The combined effects of ENSO and the 11 year solar cycle on the Northern Hemisphere polar stratosphere

Abstract

The combined effects of El Niño-Southern Oscillation (ENSO) and the 11 year solar cycle on the Northern Hemisphere polar stratosphere have been analyzed in the Whole Atmosphere Community Climate Model version 3 in the absence of the quasi-biennial oscillation. The polar response to ENSO agrees with previous studies during solar minimum; composites of warm minus cold ENSO events show a warmer polar stratosphere and a weaker polar vortex, propagating downward as the winter evolves. During solar maximum conditions, little downward propagation of the ENSO signal is simulated, leading to colder temperatures and stronger winds in the polar lower stratosphere. The analysis of the Eliassen-Palm flux and wave index of refraction shows that this is mainly due to a reduction of upward propagating extratropical planetary wave number 1 component caused by changes in the background winds in the subtropics related to a warmer tropical upper stratosphere during solar maximum. The effect of the 11 year solar cycle variability on the polar stratosphere is not significant during cold ENSO events until February. During warm ENSO events, a statistically significant colder polar lower stratosphere and stronger polar vortex are simulated throughout the winter, and no downward propagation of this signal occurs. This is mainly due to the combined effects of solar maximum and warm ENSO conditions on the wave mean flow interaction. These results show a nonlinear behavior of the extratropical stratosphere response to the combination of the two forcings and highlight the need to stratify with respect to ENSO and solar conditions and analyze the seasonal march throughout the winter.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7hm595v

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2011-12-13T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact