Large-Scale Energy Transformations in the High Latitudes of the Northern Hemisphere

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  • 1 Department of Atmospheric Science, University of Missouri-Columbia, Columbia. MO 65211
  • | 2 Department of Physics, Faculty of Science, University of Lisbon. 1200 Lisbon, Portugal
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Abstract

The kinetic energy balance and kinetic energy source are studied for high latitudes north of 55°N with twice daily upper air observations during a seven-year period from 1973 to 1979. Energy variables are presented for 5° latitudinal zones from 55 to 75°N and for the polar cap north of 75°N. Spatial distributions of important energy variables are also presented.

The upper-level maximum of the cross-isobaric generation in high latitudes is observed in the lower stratosphere above the tropopause level in the winter and becomes insignificant during the summer. The flux convergence of potential energy from the source in lower latitudes is identified as the single major source of kinetic energy in higher latitudes. The contribution of the baroclinic conversion is minor. Examination during the FGGE winter indicates that the cold air outbreaks of the Asian winter monsoon are associated with noticeable changes in the hemispherical distributions of the fields of vertical motion and energetics in the high latitudes.

Abstract

The kinetic energy balance and kinetic energy source are studied for high latitudes north of 55°N with twice daily upper air observations during a seven-year period from 1973 to 1979. Energy variables are presented for 5° latitudinal zones from 55 to 75°N and for the polar cap north of 75°N. Spatial distributions of important energy variables are also presented.

The upper-level maximum of the cross-isobaric generation in high latitudes is observed in the lower stratosphere above the tropopause level in the winter and becomes insignificant during the summer. The flux convergence of potential energy from the source in lower latitudes is identified as the single major source of kinetic energy in higher latitudes. The contribution of the baroclinic conversion is minor. Examination during the FGGE winter indicates that the cold air outbreaks of the Asian winter monsoon are associated with noticeable changes in the hemispherical distributions of the fields of vertical motion and energetics in the high latitudes.

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