20 YEARS OF ATMOSPHERIC (CO2)-C-14 OBSERVATIONS AT SCHAUINSLAND STATION, GERMANY

Authors
Citation
I. Levin et B. Kromer, 20 YEARS OF ATMOSPHERIC (CO2)-C-14 OBSERVATIONS AT SCHAUINSLAND STATION, GERMANY, Radiocarbon, 39(2), 1997, pp. 205-218
Citations number
20
Language
INGLESE
art.tipo
Article
Journal title
ISSN journal
0033-8222
Volume
39
Issue
2
Year of publication
1997
Pages
205 - 218
Database
ISI
SICI code
0033-8222(1997)39:2<205:2YOA(O>2.0.ZU;2-1
Abstract
We present and discuss quasi-continuous long-term (CO2)-C-14 observati ons from the continental background station Schauinsland (48 degrees N , 8 degrees E, 1205 m asl, Black Forest, southern Germany). The observ ed steady decline of atmospheric (CO2)-C-14 from 1977 to 1996 can be d escribed by a single exponential function with an e-folding time of(16 .3 +/- 0.2) yr. Summer means (May to August) in atmospheric (CO2)-C-14 at Schauinsland compare within Delta(14)C = +/-4 parts per thousand w ith measurements made on individual rings from a tree grown in the nea r vicinity of the Schauinsland site. Both data sets are slightly deple ted by up to 5 parts per thousand if compared to maritime background m easurements of atmospheric (1)4CO(2) made at Izana, Tenerife. This is due to the influence of fossil fuel CO2 emissions over the European co ntinent as well as generally in mid latitudes of the Northern Hemisphe re. delta(13)C analyses from the Schauinsland samples show mean season al variations with an amplitude of +/-0.4 parts per thousand, caused b y atmosphere-biosphere exchange, and a mean decrease from 1977 to 1996 of delta(13)C = -0.017 parts per thousand yr(-1). This trend is mainl y due to an increasing quantity of fossil fuel CO2 in the atmosphere, depleted in C-13/C-12 ratio, and compares well to trends measured at o ther stations in mid-to-high northern latitudes.