Open AccessLong‐period changes in the bottom water flowing through Vema Channel
Author(s) -
Hogg Nelson G.,
Zenk Walter
Publication year - 1997
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 - 10.1029/97jc00591
Subject(s) - hydrography , bottom water , water mass , channel (broadcasting) , geology , oceanography , period (music) , environmental science , structural basin , antarctic bottom water , potential temperature , climatology , geomorphology , physics , acoustics , electrical engineering , engineering
Further details of the “warming” of bottom water flowing through the Vema Channel, first reported by Zenk and Hogg [1996], are given. Because cross‐channel gradients of temperature are large and the channel is narrow, careful analysis is required to determine whether or not the bottom water temperature minimum was adequately sampled by a particular station or cruise. During a period from 1972 to 1996, at least 14 visits with quality hydrographic measurements have been made to the region. Of these, 11 were judged successful, and their data indicate an abrupt rise in potential temperature by 0.03°C from −0.18°C to −0.15°C in the early 1990s that has remained until the latest observation in the spring of 1996. Although this observation is consistent with the report of warming of Antarctic Bottom Water in the Argentine Basin by Coles et al [1996], their associated conclusion that this water mass has also freshened by 0.008 psu (on potential density surfaces) is in contradiction with our finding of no measurable change.