Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Kosta Telegadas x
  • Refine by Access: All Content x
Clear All Modify Search
Kosta Telegadas

Abstract

The large scale atmospheric nuclear testing in 1961 and 1962 afforded the opportunity of observing changes in the distribution of radioactivity and its relationship to stratospheric circulation patterns. Air-craft observations in early 1963 from 15 to 21 km over the Northern Hemisphere and balloon observations to 30 km at 31N together with 50-mb constant pressure charts suggest that most of the debris injected into the polar stratosphere during November-December 1962 was confined to a relatively small volume north of 70N. This debris did not appreciably affect the zone south of 70N until February 1963 when the circumpolar vortex split into two cyclonic cells and moved southward, one cell over Europe, the other over Canada and the United States. This contaminant was then observed as far south as 25N.

An anticyclone which moved over Alaska during February 1963 had different radioactivity characteristics than did the polar vortex. These well-defined large-scale eddies maintained their identity until May 1963 when the stratospheric distribution of radioactivity became more homogeneous.

Full access
Robert J. List
and
Kosta Telegadas

Abstract

Since 1952 a number of radioactive substances suitable for use as atmospheric tracers have been injected into the stratosphere. Information on large-scale stratospheric processes derived from measurements of strontium-90, carbon-14, tungsten-185, rhodium-102, cadmium-109 and plutonium-238 is summarized. Although the tracer data are too sparse to define an unambiguous model of the large-scale circulation features of the stratosphere, they should not be ignored in the process of constructing models from other considerations.

The tracer data indicate a summer-to-winter hemisphere flow above about 37 km and a mean descending motion in the winter stratosphere between 25° and about 70°. Ascending motion occurs near the equatorial tropopause and in the lower winter stratosphere poleward of 70°. Virtually the entire summer stratosphere and the winter stratosphere equatorward of 25° between 18 and 25 km is dominated by mixing processes with no evidence of organized circulations in the meridional plane.

Full access