RRS James Clark Ross Cruise JR55, 21 Nov-14 Dec 2000. Drake Passage repeat hydrography: WOCE Southern Section 1b – Burdwood Bank to Elephant Island

This report describes the sixth repeat hydrography section across Drake Passage, first established during the International World Ocean Circulation Experiment. Through continuation of this time series the nature of the interannual variability in the location and properties of the ACC at this choke point between South America and the Antarctic Peninsula can be determined. Across the 644km section from Burdwood Bank to Elephant Island, thirty-one CTD/LADCP stations (including one test station) were made on the southbound journey with a maximum station spacing of 33km. Water samples were drawn for salinity analysis and CTD conductivity calibration. The underway measurements included: Vessel Mounted Acoustic Doppler Current Profiler, measuring currents to depths of 300m beneath the ship, navigation, sea surface temperatures recorded by thermosalinograph, meteorology logged via the oceanlogger system and Simrad echo sounder determining water depths. CTD station 32 was at the Rothera time series (RaTs) site just off Rothera Pier, carried out primarily for collected water samples for nutrient analysis back at SOC.On the northbound crossing of Drake Passage, to the west of the southbound section, an extra two full depth CTD/LADCP stations were made to test CTD DEEP03. XBTs were deployed at two hourly intervals and underway data logged. This report was compiled by Louise M. Duncan.