title: Regional 14CO2 offsets in the troposphere: magnitude, mechanisms, and consequences.
abstract: Radiocarbon dating methods typically assume that there are no significant tropospheric (14)CO(2) gradients within the low- to mid-latitude zone of the Northern Hemisphere. Comparison of tree ring (14)C data from southern Germany and Anatolia supports this assumption in general but also documents episodes of significant short-term regional (14)CO(2) offsets. We suggest that the offset is caused by an enhanced seasonal (14)CO(2) cycle, with seasonally peaked flux of stratospheric (14)C into the troposphere during periods of low solar magnetic activity, coinciding with substantial atmospheric cooling. Short-term episodes of regional (14)CO(2) offsets are important to palaeoclimate studies and to high-resolution archaeological dating.
authors.affiliation: Heidelberger Akademie der Wissenschaften, Institut für Umweltphysik der Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany. bernd.kromer@iup.uni-heidelberg.de
authors.forename: B
authors.initials: B
authors.lastname: Kromer
authors.forename: S W
authors.initials: SW
authors.lastname: Manning
authors.forename: P I
authors.initials: PI
authors.lastname: Kuniholm
authors.forename: M W
authors.initials: MW
authors.lastname: Newton
authors.forename: M
authors.initials: M
authors.lastname: Spurk
authors.forename: I
authors.initials: I
authors.lastname: Levin
mesh_terms: D001106:Archaeology; D001272:Atmosphere; D002138:Calibration; D002245:Carbon Dioxide; D002250:Carbon Radioisotopes; D002980:Climate; D005858:Germany; D019083:Mediterranean Region; D009792:Oceans and Seas; D012621:Seasons; D013995:Time; D014197:Trees / Q000254:growth & development; D014421:Turkey; D014934:Wood
chemical_list: D002250:Carbon Radioisotopes; D002245:Carbon Dioxide