Publication Abstracts

DallaSanta and Gerber 2020

DallaSanta, K., and E.P. Gerber, 2020: Downward migration of the zonal-mean circulation in the tropical atmosphere. Geophys. Res. Lett., 47, no. 18, e2020GL088084, doi:10.1029/2020GL088084.

The annular modes of the extratropical atmosphere have received much attention for quantifying variability of the jet streams and storm tracks, despite the fact that the midlatitude circulation itself does not vary uniformly with longitude. While tropical fluctuations in geopotential height have lower amplitude than in the extratropics, they exhibit stronger zonal coherence, or dynamical annularity. A simple index is developed to characterize zonal-mean anomalies of the tropical circulation. It reveals that anomalies in geopotential height and zonal wind migrate downward from the upper troposphere to the surface on a time scale of about 10 days. These features are distinguishable from known modes of tropical variability, the Madden-Julian Oscillation in particular. Evidence from reanalysis and idealized model experiments confirms that this downward migration is quite generic and driven by mechanically forced variations in the strength of the Hadley circulation on subseasonal time scales.

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BibTeX Citation

  author={DallaSanta, K. and Gerber, E. P.},
  title={Downward migration of the zonal-mean circulation in the tropical atmosphere},
  journal={Geophys. Res. Lett.},

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RIS Citation

ID  - da00300e
AU  - DallaSanta, K.
AU  - Gerber, E. P.
PY  - 2020
TI  - Downward migration of the zonal-mean circulation in the tropical atmosphere
JA  - Geophys. Res. Lett.
VL  - 47
IS  - 18
SP  - e2020GL088084
DO  - 10.1029/2020GL088084
ER  -

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