TROPOSPHERIC 14C VALUES IN THE PACIFIC
NORTHWEST AND THE ARCTIC BASIN DURING 1964
JAMES A, YOUNG, NILS E. ERICKSON, and ARTHUR W. FAIRHALL
University of Washington, Seattle, Washington
ABSTRACT
Samples of atmospheric CO, were collected by using a molecular sieve
and counted for their ‘“C content. Taking 0.95 of the National Bureau of
Standards oxalic acid standard as the pre-1945 level of ‘4C in the
atmosphere, the results are expressed as percent above normal. Dur-
ing the summer of 1963, tropospheric levels reached about 115% above
normal, followed by a rapid drop to about 88% above normal in the
early fail of 1963, a level which was maintained until May 1964, when
a new summerrise was noted. The sudden drop in C specific activity
is attributed to exchange of atmospheric CO, with dissolved CO, in the
ocean. Increases in the tropospheric 'C concentration is attributable
to injection of CO, of high specific activity from the stratosphere.
Samples of CO, taken during the passage of storm fronts give evidence
of this injection, as well as evidence of exchange with oceanic CQ,.
INTRODUCTION
Samples of atmospheric CO, of from 2 to 8 liters are collected
periodically for ‘*C analysis from several locations in the state of
Washington and the Arctic basin. The collection system consists ofa
Linde type 4-A molecular sieve designed for field use.
The first successful use of a molecular-sieve material for sam-
pling of atmospheric CO, for '4C was apparently made by Fergusson.'
Previous investigators attempting to use this material for similar
studies experienced difficulty because the untreated sieve material has
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