TY - JOUR
T1 - Different ENSO teleconnections and their effects on the stratospheric polar vortex
AU - Garfinkel, C. I.
AU - Hartmann, Dennis L.
PY - 2008/9/27
Y1 - 2008/9/27
N2 - Reanalysis data are used to study the El Niño-Southern Oscillation (ENSO) signal in the troposphere and stratosphere during the late fall to midwinter period. Warm ENSO events have extratropical tropospheric teleconnections that increase the wave 1 eddies and reduce the wave 2 eddies, as compared to cold ENSO. The increase in wave 1 overwhelms the decrease in wave 2, so the net effebt is a weakened vortex. This modification in tropospheric wave forcing is induced by a deepening of the wintertime Aleutian low via the Pacific-North America pattern (PNA). Model results are also used to verify that the PNA is the primary mechanism through which ENSO modulates the vortex. During easterly Quasi-Biennial Oscillation (EQBO), warm ENSO does not show a PNA response in the observational record. Consequently, the polar vortex does not show a strong response to the different phases of ENSO under EQBO, nor to the different phases of QBO under WENSO. It is not clear whether the lack of a PNA response to warm ENSO during EQBO is a real physical phenomenon or a feature of the limited data record we have.
AB - Reanalysis data are used to study the El Niño-Southern Oscillation (ENSO) signal in the troposphere and stratosphere during the late fall to midwinter period. Warm ENSO events have extratropical tropospheric teleconnections that increase the wave 1 eddies and reduce the wave 2 eddies, as compared to cold ENSO. The increase in wave 1 overwhelms the decrease in wave 2, so the net effebt is a weakened vortex. This modification in tropospheric wave forcing is induced by a deepening of the wintertime Aleutian low via the Pacific-North America pattern (PNA). Model results are also used to verify that the PNA is the primary mechanism through which ENSO modulates the vortex. During easterly Quasi-Biennial Oscillation (EQBO), warm ENSO does not show a PNA response in the observational record. Consequently, the polar vortex does not show a strong response to the different phases of ENSO under EQBO, nor to the different phases of QBO under WENSO. It is not clear whether the lack of a PNA response to warm ENSO during EQBO is a real physical phenomenon or a feature of the limited data record we have.
UR - http://www.scopus.com/inward/record.url?scp=56549112245&partnerID=8YFLogxK
U2 - 10.1029/2008JD009920
DO - 10.1029/2008JD009920
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AN - SCOPUS:56549112245
SN - 0148-0227
VL - 113
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
IS - 18
M1 - D18114
ER -