Measurements of CO2, its stable isotopes, O2/N2, and 222Rn at Bern, Switzerland

[摘要] A one-year time series of atmospheric CO₂ measurements fromBern, Switzerland, is presented. O₂/N₂ and Ar/N₂ ratiosas well as stable carbon and oxygen isotopes of CO₂ andδ²⁹N₂, δ³⁴O₂ and δ³⁶Ar weremeasured periodically during a one year period. Additionally, the²²²Rn activity was measured during three months in the winter2004. Using the correlation from short-term fluctuations of CO₂and ²²²Rn we estimated a mean CO₂ flux density betweenFebruary 2004 and April 2004 in the region of Bern of95±39 tC km^–2month^–1. The continuousobservations of carbon dioxide and associated tracers shed lighton diurnal and seasonal patterns of the carbon cycle in an urbanatmosphere. There is considerable variance in nighttimeδ¹³C and δ¹⁸O of source CO₂ throughout theyear, however, with generally lower values in winter compared tosummertime. The O₂:CO₂ oxidation ratio during the nighttimebuild-up of CO₂ varies between –0.96 and–1.69 mol O₂/mol CO₂. Furthermore, Ar/N₂measurements showed that artifacts like thermal fractionation atthe air intake are relevant for high precision measurements ofatmospheric O₂.

[学科分类] 大气科学