Age distribution of Antarctic Bottom Water off Cape Darnley, East Antarctica, estimated using chlorofluorocarbon and sulfur hexafluoride

Chlorofluorocarbon (CFC) and sulfur hexafluoride (SF6) were used to investigate the timescale of Antarctic Bottom Water (AABW) that spreads off Cape Darnley (CD) in East Antarctica. The age of the AABW was estimated based on the observed SF6/CFC-12 ratio while taking into account tracer dilution by Lower Circumpolar Deep Water. Along the western canyons off CD and the similar to 3000 to 3500 m isobaths, the bottom water age was <5 years, reflecting the spread of newly formed CD Bottom Water. Higher ages of similar to 8 years obtained for areas east of CD and > 20 years in the northwestern offshore region indicate inflows of AABW through the Princess Elizabeth Trough and Weddell Sea Deep Water, respectively. This study determined the age distribution in the region off CD, where three different types of AABW spread.

Automated summary

This study used CFC and SF6 tracers to investigate the timescale of Antarctic Bottom Water (AABW) spreading in Cape Darnley, East Antarctica. The results showed that the age of the bottom water varied with location, indicating different spreading processes of AABW.