RRS James Clark Ross Cruise 195, 18-29 Nov 2009. Drake Passage repeat hydrography of WOCE section SR1b: a beginners’ guide

This report describes the 16th occupation of the Drake Passage CTD section, established during the World Ocean Circulation Experiment as repeat section SR1b. It was first occupied by National Oceanography Centre (previously IOSDL and then SOC) in collaboration with the British Antarctic Survey in 1993, and has been re-occupied most years since then. Thirty one full depth stations were performed during JR195: two test stations, and 29 of the 30 nominal stations for the SR1b Drake Passage section. Two 500 m stations were added as part of POL's cruise JR198. The CTD was an underwater SBE 9 plus unit equipped with the following sensors: dual temperature and conductivity sensors, a pressure sensor encased in the SBE underwater unit, a SBE-43 oxygen probe, an Aquatracka MKIII fluorometer, a transmissometer, an upwardlooking downwelling PAR sensor, and an altimeter. A downward-looking LADCP (RDI Workhorse Monitor 300 kHz) was deployed on all stations, except for the two 500 m stations when it was replaced by a 600 kHz LADCP from Bangor University. Various underway measurements were obtained, including navigation, VM-ADCP, sea surface temperature and salinity, water depth and various meteorological parameters.