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Measurements of concentrations of chlorofluoromethanes (CFMs) carbon dioxide and carbon isotope ratio in stratospheric and tropospheric air by grab-sampling systemsMeasurements of concentrations of chlorofluoromethanes (CFMs), carbon dioxide and carbon isotope ratio in stratospheric and tropospheric air by grab-sampling systems are reported. The balloon-borne grab-sampling system has been launched from Sanriku Balloon Center three times since 1981. It consists of: (1) six sampling cylinders, (2) eight motor driven values, (3) control and monitor circuits, and (4) pressurized housing. Particular consideration is paid to the problem of contamination. Strict requirements are placed on the choice of materials and components, construction methods, cleaning techniques, vacuum integrity, and sampling procedures. An aluminum pressurized housing and a 4-m long inlet line are employed to prevent the sampling air from contamination by outgassing of sampling and control devices. The sampling is performed during the descent of the system. Vertical profiles of mixing ratios of CF2Cl2, CFCl3 and CH4 are given. Mixing ratios of CF2Cl2 and CFCl3 in the stratosphere do not show the discernible effect of the increase of those in the ground level background, and decrease with altitude. Decreasing rate of CFCl3 is larger than that of CF2Cl2. CH4 mixing ratio, on the other hand, shows diffusive equilibrium, as the photodissociation cross section of CH4 is small and concentrations of OH radical and 0(sup I D) are low.
Document ID
19860018341
Document Type
Conference Paper
Authors
Itoh, T.
(Tokyo Univ.)
Kubo, H.
(Tokyo Univ.)
Honda, H.
(Tokyo Univ.)
Tominaga, T.
(Tokyo Univ.)
Makide, Y.
(Tokyo Univ.)
Yakohata, A.
(Tokyo Univ.)
Sakai, H.
(Tokyo Univ.)
Date Acquired
August 12, 2013
Publication Date
December 1, 1985
Publication Information
Publication: International Council of Scientific Unions Handbook for MAP, Vol. 18
Subject Category
Geophysics
Accession Number
86N27813
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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