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Observations and Modelling of the 14CO2 Variability in the Polar Atmosphere of the Southern Hemisphere

Description: Das Projekt "Observations and Modelling of the 14CO2 Variability in the Polar Atmosphere of the Southern Hemisphere" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. The project focuses on the measurement and interpretation of atmospheric 14C variations in high latitudes of the southern hemisphere. We will investigate the global trend in the interhemispheric 14C gradient which is naturally caused by the large 14CO2 uptake in the Southern Ocean due to vigorous gas exchange and a strong 14C disequilibrium between the atmosphere and aged surface water around Antarctica. Anthropogenic emissions of fossil fuel, 14C-free CO2 in the northern hemisphere counteract the natural gradient. Seasonal variations in the CO2 gas exchange rate between atmosphere and ocean surface lead to seasonally varying 14CO2 fluxes, which contribute to the seasonality of the observed 14C signal in the southern polar troposphere. This ocean signal is superimposed by the seasonal injection of stratospheric air (= source of natural, cosmogenic 14C). Both components can, in principle, be decoupled by 10Be/7Be observations and respective model simulations. With an existing box model of the atmosphere for 14CO2 to which an ocean model will be coupled in the frame of this project, we will simulate and quantify the oceanic and stratospheric contributions to the observed 14C variability. This will allow new constraints on the respective processes, i.e. gas exchange between stratosphere, troposphere and ocean. Furthermore, the observed inter-annual 14C variability, its relation to ENSO and the associated variable stratification of the oceans in the southern hemisphere will by studied.

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SupportProgram

Origin: /Bund/UBA/UFORDAT

Tags: Heidelberg ? Fossiler Brennstoff ? Geografische Koordinaten ? Blei ? Kohlendioxid ? Schadstoffemission ? Luft ? Bodenaustausch ? Antarktis ? Jahreszeit ? Bodenluft ? Gasaustausch ? Meeresoberfläche ? Oberflächengewässer ? Stratosphäre ? Troposphäre ? Meeresgewässer ? Modellierung ? Messung ? Atmosphäre ? Fläche ? Schadstoffquelle ? Globale Aspekte ? Südlicher Ozean ? Anthropogener Einfluss ? Betrachtung ? Grundsatz ? Bemessung ? Grundsätze ? Oberfläche ? Projekt ? Vorgabe ? austauschen ? bestehend ? jahreszeitlich ?

Region: Baden-Württemberg

Bounding box: 9° .. 9° x 48.5° .. 48.5°

License: cc-by-nc-nd/4.0

Language: Deutsch

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Time ranges: 2005-08-01 - 2006-07-31

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