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SUMMARY:The Southern Ocean carbon cycle: Insights from a recently installe
 d atmospheric O2 and CO2 measurement system at the Halley Research Station
 \, Antarctica - Thomas Barningham \, UEA\, School of Environmental Science
 s
DTSTART:20170517T130000Z
DTEND:20170517T140000Z
UID:TALK71924@talks.cam.ac.uk
CONTACT:Dr Alexandra Weiss
DESCRIPTION:The Southern Ocean represents 40% of the global ocean anthropo
 genic CO2 uptake. The strength of this sink is determined by a delicate ba
 lance between opposing biogeochemical processes: the upwelling of deep wat
 er rich in dissolved inorganic carbon and the drawdown of anthropogenic CO
 2 by biological production. Monitoring these processes is an inherently di
 fficult task given the scarcity of observations and thus is the source of 
 much scientific debate. Due to compounding physical\, biological and chemi
 cal factors\, the air-sea flux of CO2 is dampened and therefore difficult 
 to detect. In this talk I will discuss how the addition of atmospheric O2 
 observations circumvents these problems and allows one to detect a much la
 rger signal from the carbon cycle processes that drive air-sea CO2 fluxes.
 \n\nI will present the first year of data from a very recent installation 
 of a fully automated\, continuous atmospheric O2 and CO2 measurement syste
 m at the Clean Air Sector Laboratory (CASLab) at the Halley Research Stati
 on\, Antarctica\, in collaboration with the British Antarctic Survey. I wi
 ll present the seasonal cycle in atmospheric potential oxygen (APO = O2 + 
 1.1CO2)\, which is conservative with respect to terrestrial biosphere proc
 esses and therefore largely represents the seasonality of the above mentio
 ned Southern Ocean carbon cycle processes. I compare this to other APO sta
 tions across the Southern Ocean and to modelled APO at the measurement sit
 e and comment on the significance of the differences. Finally\, I interpre
 t synoptic scale variability in APO in conjunction with other atmospheric 
 species observed at the CASLab\, by utilising air mass history “footprin
 ts” derived from the  NAME (Numerical Atmospheric dispersion Modelling E
 nvironment) atmospheric transport model. From this one can discern differe
 nt air masses deriving off the Southern Ocean where marine biological prod
 uctivity dominates air-sea gas exchange of O2\, or\, conversely\, where de
 ep ocean ventilation dominates.\n\n
LOCATION:British Antarctic Survey\, Innovation Centre\, Seminar Room 307
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