The Distribution of Tropospheric Planetary Radiation in the Southern Hemisphere

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  • a The Rand Corporation, Santa Monica, Calif. 90406
  • | b Dept. of Atmospheric & Oceanic Science, University of Michigan, Ann Arbor 48105
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Abstract

The planetary radiation for the Southern Hemisphere troposphere has been calculated from climatological data for January and July. Zonally averaged profiles of cooling/heating rates are presented. In addition, calculations have been made for selected latitudes and longitudes to illustrate the variation from the mean zonal rates. The outgoing planetary radiation and the zonally averaged net flux divergence are also discussed.

The heating/cooling rate calculations show that maximum cooling occurs in the mid-troposphere and is larger over the oceans than the continents, with longitudinal variations reaching 1C day−1. Results are similar to those of Katayama for the Northern Hemisphere with the exception that we find significant heating at the base of the cirrus clouds.

The hemispheric distribution of outgoing flux agrees qualitatively with that derived from satellite measurements. The annual longitudinally averaged results agree closely with those of Sasamori et al. except in the vicinity of the polar front where our outgoing fluxes are about 25 ly day−1 smaller while in the polar latitudes our results are larger by a comparable amount. Many of the variations are directly attributable to cloud cover and the need for additional cloud data is exphasized.

Abstract

The planetary radiation for the Southern Hemisphere troposphere has been calculated from climatological data for January and July. Zonally averaged profiles of cooling/heating rates are presented. In addition, calculations have been made for selected latitudes and longitudes to illustrate the variation from the mean zonal rates. The outgoing planetary radiation and the zonally averaged net flux divergence are also discussed.

The heating/cooling rate calculations show that maximum cooling occurs in the mid-troposphere and is larger over the oceans than the continents, with longitudinal variations reaching 1C day−1. Results are similar to those of Katayama for the Northern Hemisphere with the exception that we find significant heating at the base of the cirrus clouds.

The hemispheric distribution of outgoing flux agrees qualitatively with that derived from satellite measurements. The annual longitudinally averaged results agree closely with those of Sasamori et al. except in the vicinity of the polar front where our outgoing fluxes are about 25 ly day−1 smaller while in the polar latitudes our results are larger by a comparable amount. Many of the variations are directly attributable to cloud cover and the need for additional cloud data is exphasized.

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