Physikalisches Kolloquium

Sommersemester 2017

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Kirchhoff-Institut für Physik, Otto-Haxel-Hörsaal
freitags 17:15

19.5.2017 17:00
Prof. Dr. Ingeborg Levin, Institut für Umweltphysik, Universität Heidelberg
KIP, INF 227, Otto-Haxel-Hörsaal

Atmospheric nuclear weapon testing during the cold war in the 1950s and 1960s has been worrying, though including a unique beneficial aspect in the area of environmental sciences. The artificial nuclear production of more than 6 x 1028 atoms or about 1.4 tons of 14C led to a doubling of the 14C/C ratio in tropospheric CO2 of the Northern Hemisphere. The prominent so-called bomb spike peaking in 1963 can be used as transient tracer to understand carbon dynamics in the Earth System. This information is indispensable to estimate the residence times of carbon in ocean and biosphere reservoirs. Knowing these residence times is key to model the fate of man-made CO2 emissions from burning of fossil fuels and land-use changes. Today, the transient bomb-radiocarbon signal has levelled-off in most carbon compartments and the anthropogenic input of 14C-free fossil fuel CO2 dominates the decreasing trend of the 14C/C ratio in tropospheric CO2. On the regional scale, the lack of 14C in fossil fuel CO2 emissions uniquely marks this anthropogenic CO2 component, therewith allowing a so-called top-down verification of fossil CO2 emissions and their changes. I will present some prominent examples where the 14C bomb spike is successfully used to unravel dynamic processes in the carbon cycle and introduce our activities as Central Radiocarbon Laboratory in the recently established Integrated Carbon Observation Syste m Research Infrastructure (ICOS RI).
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