Influence of stratospheric circulation on the predictability of the tropospheric Northern Annular Mode

Hitoshi Mukougawa, Toshihiko Hirooka, Yuhji Kuroda

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

[1] Influence of stratospheric circulation on the predictability of the tropospheric Northern Hemisphere, Annular Mode (NAM) in the boreal winter is examined using 5-year archive of 1-month ensemble forecast dataset provided by the Japan Meteorological Agency (JMA). It is found that the prediction skill of the 7-day averaged ensemble-mean NAM index in the upper troposphere is significantly improved for 5- to 13-day forecast when negatively large NAM indices are observed in the stratosphere around 30 hPa at the initial time of forecast in comparison with stratospheric positive NAM events. The regression analysis also supports the significant relationship between large prediction error of the upper tropospheric NAM. index and stratospheric westerly anomalies. The asymmetric response of the forecast skill of the upper tropospheric NAM index to the polarity of the stratospheric NAM anomaly is also discussed in terms of the dependence of the upward propagation of planetary waves on stratospheric zonal wind anomalies.

Original languageEnglish
Article numberL08814
JournalGeophysical Research Letters
Volume36
Issue number8
DOIs
Publication statusPublished - Apr 28 2009

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Arctic Oscillation
Northern Hemisphere
forecasting
anomalies
anomaly
planetary wave
zonal wind
stratosphere
prediction
predictions
troposphere
planetary waves
westerly
winter
regression analysis
Japan
polarity
propagation
forecast
index

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Influence of stratospheric circulation on the predictability of the tropospheric Northern Annular Mode. / Mukougawa, Hitoshi; Hirooka, Toshihiko; Kuroda, Yuhji.

In: Geophysical Research Letters, Vol. 36, No. 8, L08814, 28.04.2009.

Research output: Contribution to journalArticle

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