The freshwater composition of the Fram Strait outflow derived from a decade of tracer measurements

Paul A. Dodd, Benjamin Rabe, Edmond Hansen, Eva Falck, Andreas Mackensen, Eelco Rohling, Colin Stedmon, Svein Kristiansen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The composition of the Fram Strait freshwater outflow is investigated by comparing 10 sections of concurrent salinity, δ18O, nitrate and phosphate measurements collected between 1997 and 2011. The largest inventories of net sea ice meltwater are found in 2009, 2010 and 2011. The 2009–2011 sections are also the first to show positive fractions of sea ice meltwater at the surface near the core of the EGC. Sections from September 2009–2011 show an increased input of sea ice meltwater at the surface relative to older September sections. This suggests that more sea ice now melts back into the surface in late summer than previously. Comparison of April, July and September sections reveals seasonal variations in the inventory of positive sea ice meltwater, with maximum inventories in September sections. The time series of sections reveals a strong anti-correlation between meteoric water and net sea ice meltwater inventories, suggesting that meteoric water and brine may be delivered to Fram Strait together from a common source. We find that the freshwater outflow at Fram Strait exhibits a similar meteoric water to net sea ice meltwater ratio as the central Arctic Ocean and Siberian shelves, suggesting that much of the sea ice meltwater and meteoric water at Fram Strait may originate from these regions. However, we also find that the ratio of meteoric water to sea ice meltwater inventories at Fram Strait is decreasing with time, due to an increased surface input of sea ice meltwater in recent sections
Original languageEnglish
JournalJournal of Geophysical Research - Oceans
Volume117
Issue numberC11
Pages (from-to)1-26
ISSN2169-9380
DOIs
Publication statusPublished - 2012

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