کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5477720 1521569 2017 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Variation of atmospheric 14CO2 and its spatial distribution
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی انرژی هسته ای و مهندسی
پیش نمایش صفحه اول مقاله
Variation of atmospheric 14CO2 and its spatial distribution
چکیده انگلیسی
The atmospheric 14CO2 is usually presented in the Δ14C notation, which cannot reflect its absolute quantity change. This article presents the atmospheric radiocarbon activity concentrations (aacn, reported in mBq/m3) in recent years at nine observation stations. The aacn at Schauinsland decrease from 1977 to 1993 but between 1993 and 2003 keeps at a relative steady state. Atmospheric aacns were higher in the northern hemisphere than that in the southern hemisphere. The aacns in the northern hemisphere show clear seasonal cycle with higher value in winter and lower value in summer, while this seasonality is not obvious in the southern hemisphere. Vegetation plays as a role of sink in summer and a role of source in winter, and atmosphere-biosphere radiocarbon exchange might be the main driver of the aacns seasonality. The annual mean aacns in both hemispheres show slightly increasing trends since 2002, which may be mainly caused by decreasing air-sea 14C flux as the air-sea 14C gradient decline.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Environmental Radioactivity - Volumes 169–170, April 2017, Pages 116-121
نویسندگان
,