Open AccessNordic seas transit time distributions and anthropogenic CO 2
Author(s) -
Olsen Are,
Omar Abdirahman M.,
Jeansson Emil,
Anderson Leif G.,
Bellerby Richard G. J.
Publication year - 2010
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jc005488
Subject(s) - tracer , dissolved organic carbon , alkalinity , environmental science , arctic , water mass , carbon fibers , oceanography , atmospheric sciences , geology , chemistry , materials science , physics , organic chemistry , nuclear physics , composite material , composite number
The distribution and inventory of anthropogenic carbon ( DIC ant ) in the Nordic seas are determined using the transit time distribution (TTD) approach. To constrain the shape of the TTDs in the Nordic seas, CO 2 is introduced as an age tracer and used in combination with water age estimates determined from CFC‐12 data. CO 2 and CFC‐12 tracer ages constitute a very powerful pair for constraining the shape of TTDs. The highest concentrations of DIC ant appear in the warm and well‐ventilated Atlantic water that flows into the region from the south, and concentrations are typically lower moving west into the colder Arctic surface waters. The depth distribution of DIC ant reflects the extent of ventilation in the different areas. The Nordic seas DIC ant inventory for 2002 was constrained to between 0.9 and 1.4 Gt DIC ant , corresponding to ∼1% of the global ocean DIC ant inventory. The TTD‐derived DIC ant estimates were compared with estimates derived using four other approaches, revealing significant differences with respect to the TTD‐derived estimates, which can be related to issues with some of the underlying assumptions of these other approaches. Specifically, the Tracer combining Oxygen, inorganic Carbon and total Alkalinity (TrOCA) method appears to underestimate DIC ant in the Nordic seas, the ΔC* shortcut and the approach of Jutterström et al. (2008) appear to overestimate DIC ant at most depths in this area, and finally the approach of Tanhua et al. (2007) appears to underestimate Nordic seas DIC ant below 3000 m and overestimate it above 1000 m.