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AGU: Journal of Geophysical Research, Atmospheres

 

Keywords

  • Solar activity
  • energetic particle precipitation
  • stratosphere circulation

Index Terms

  • Atmospheric Processes: Climate change and variability
  • Atmospheric Processes: Middle atmosphere dynamics
  • Atmospheric Composition and Structure: Middle atmosphere: constituent transport and chemistry
  • Atmospheric Processes: General circulation
  • Ionosphere: Particle precipitation
Abstract
Cited By (7)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, D16106, 16 PP., 2008
doi:10.1029/2007JD008915

Geomagnetic perturbations on stratospheric circulation in late winter and spring

Hua Lu

Physical Sciences Division, British Antarctic Survey, Cambridge, UK

Mark A. Clilverd

Physical Sciences Division, British Antarctic Survey, Cambridge, UK

Annika Seppälä

Physical Sciences Division, British Antarctic Survey, Cambridge, UK

Earth Observation, Finnish Meteorological Institute, Helsinki, Finland

Lon L. Hood

Lunar and Planetary Laboratory, University of Arizona, Tuczon, Arizona, USA

This study investigates if the descent of odd nitrogen, generated in the thermosphere and the upper mesosphere by energetic particle precipitation (EPP-NO x ), has a detectable impact on stratospheric wind and temperature in late winter and spring presumably through the loss of ozone and reduction of absorption of solar UV. In both hemispheres, similar downward propagating geomagnetic signals in the extratropical stratosphere are found in spring for those years when no stratospheric sudden warming occurred in mid-winter. Anomalous easterly winds and warmer polar regions are found when the 4-month averaged winter Ap index (A p ) is high, and the signals become clearer when solar F10.7 is low. In May, significant geomagnetic signals are obtained in the Northern Hemisphere when the data are grouped according to the phase of the stratospheric equatorial QBO. The magnitudes of changes in spring stratospheric wind and temperatures associated with A p signals are in the range of 10–20 m s−1 and 5–10 K, which are comparable with those of the 11-yr SC signals typically found in late winter. The spring A p signals show the opposite sign to that expected due to in situ cooling effects caused by catalytic destruction of stratospheric ozone by descending EPP-NO x . Thus it is unlikely that the in situ chemical effect of descending EPP-NO x on stratospheric ozone would have a dominant influence on stratospheric circulation. Instead, we suggest that the detected A p signals in the extratropical spring stratosphere may be an indirect consequence of geomagnetic and solar activity, dynamically induced by changes in wave ducting conditions.

Received 4 May 2007; accepted 11 June 2008; published 22 August 2008.

Citation: Lu, H., M. A. Clilverd, A. Seppälä, and L. L. Hood (2008), Geomagnetic perturbations on stratospheric circulation in late winter and spring, J. Geophys. Res., 113, D16106, doi:10.1029/2007JD008915.

Cited By

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