Atmospheric Concentrations and Inventory of Krypton-85 in 1973

Abstract

Measurements of the concentrations of85Kr in the atmosphere were made in 1973 between 1.5 and 20 kilometers. The global inventory of 8sKr for 1973 calculated from these data is 53 megacuries. The stratospheric distribution of 85Kr concentrations shows a maximum in the lower equatorial region of each hemisphere and a minimum concentration in the polar regions. This distribution tends to confirm the mean stratospheric circulation as deduced from other radioactive tracer data. Both 85Kr and Fluorocarbon-Il CC13F, here designated as F-Il) are inert gases released principally into the surface air in the temperate latitudes of the Northern Hemisphere. The stratospheric distribution of 8SKr is very similar to that of F-I. A bove 20 kilometers a photodissociation offluorocarbons may take place, producing atomic chlorine which may act as a catalyst in the destruction of stratospheric ozone. Since 85Kr has no known significant sinks and its half-life is known, measurements of the concentration of both of these gases above 20 kilometers may provide insight regarding the rate ofdissociation ofF-l 1.The radioisotope 85Kr of the noble gas krypton (half-life, 10.76 years) is produced by nuclear fission mainly as a result of the operation of nuclear reactors and, to a lesser extent, in nuclear test explosions. Al-

Methane: Interhemispheric concentration gradient and atmospheric residence time

“…Because some of these measurements are made at surface level in the tropics and others are from aircraft flying at altitudes with ambient temperatures below 0°C, the natural humidity undoubtedly varies widely. In our own data, the 21 ATMOSPHERIC LIFETIME OF CH4 If reactions 1 and 2 are the predominant mechanisms for atmospheric removal ofCH4 and CH3CC13, respectively, then the removal rates are proportional to the reaction rate constants, k, and k2, at each location in the atmosphere, and the relatively uncertain OH concentrations in the atmosphere can be essentially canceled out in a relative calculation. The best current rate constant equations for these reactions are (31) Although the available temperature range in the troposphere covers about 90'C, 80% of the removal of these molecules occurs below an altitude of 6 km, at temperatures above 275 K, with the median altitude for such reaction at about 2 km (32).…”

“…This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact. (20), 85Kr from nuclear fission (21), and CC13F, CC12F2, and other industrially significant chlorine-containing molecules (22). There have also been suggestions that the average tropospheric OH concentration might be higher in the southern hemisphere than in the northern (23)(24)(25)(26)(27), such that removal ofCH4 and CH3CC13 by reaction with OH would therefore occur more rapidly in the south than in the north.…”

A new compilation of the atmospheric 85krypton inventories from 1945 to 2000 and its evaluation in a global transport model

“…The last took place in 1998. An assessment by Telegades and Ferber (1975) indicates that less than 2 percent of the total 85 Kr world inventory in 1973 could be attributed to nuclear weapon tests conducted up to that time. Their contribution is estimated to have produced 111-185 PBq (Izrael et al, 1982;Hilbert, 1975).…”

Radioactive Noble Gases in the Terrestrial Environment

“…The ver tical profile obtained by Pannetier (1968) in 1964 over France (Fig. The average profile of ^^Kr presented by Telegadas and Ferber (1975) is based on numerous measurements over the region 35-45°N. This effect again can be attributed to large stratospheric discharge of ^^Kr during nuclear bomb tests in the early sixties.…”

“…Prior to the radioactivity measurement, the krypton gas is extracted from the atmosphere by fractional distillation of liquid air, or by selective absorption of krypton on porous materials (e.g. EPA, , 1974bStockburger and Sittkus, 1975;Telegadas and Ferber, 1975;Gudkov et al, 1976;Sittkus and Stockburger, 1976;Rozanski and Ostrowski, 1977;Ferber et al, 1977;Tertysnik et al, 1977;Stockburger et al, 1977;Wardaszko and Nidecka, 1978). Two excellent reviews on the analytical methods and techniques for ®^Kr moni toring in the atmosphere have been published by Budnitz (1973) and Jaquish and Moghissi (1973).…”