RRS James Clark Ross JR20041201 (JR111, JR115)

Cruise summary report

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Cruise Info.

Ship name (ship code)

RRS James Clark Ross (74JC)

Cruise identifier

JR20041201 (JR111, JR115)

Cruise period

2004-12-02 — 2004-12-19

Status

Completed

Port of departure

Stanley, Falkland Islands (Malvinas)

Port of return

Stanley, Falkland Islands (Malvinas)

Purpose

Research

Objectives

1) To determine the interannual variability of the position, structure and transport of the Antarctic Circumpolar Current (ACC) in Drake Passage;
2) To examine the fronts associated with the ACC, and to determine their positions and strengths;
3) By comparing geostrophic velocities with those measured directly (by the lowered ADCP), to determine the size of ageostrophic motions, and to attempt to estimate the barotropic components;
4) To examine the temperature and salinity structure of the water flowing through Drake Passage, and to identify thereby the significant water masses;
5) To calculate the total flux of water through Drake Passage by combining all available measurements.

POL Drake Passage Servicing was also undertaken on this cruise under the lead of Geoff Hargreaves, POL (JR111). The objectives were as follows:
To service the Sea Level Recorder at Port Stanley, Falkland Islands.
To recover the BPR and BPR/IES from the Drake Passage.
To deploy two BPRs and one BPR/IES in the Drake Passage.
To test, deploy and recover a RAPID lander.
To service the Sea Level Recorder at Rothera.

Chief scientist

Elizabeth J Hawker (Southampton Oceanography Centre), Michael D Sparrow (Southampton Oceanography Centre)

Project

Drake Passage repeats

Cruise report

(0.12 MB)

(1.54 MB)

Ocean/sea areas

General

South West Atlantic Ocean (limit 20W)

Specific

Southern Ocean - Drake Passage

Track charts

(0.04 MB)

(10.42 MB)

Measurements

Physical oceanography

Surface measurements underway (T,S)

Quantity: activity duration in days = 19
Description: Met and subs. underway data were collected/processed during most of the cruise.

Water bottle stations

Quantity: number of stations = 37
Description: 35 full depth CTD stations were completed and 2 repeat shallows stations for biogeochemical sampling only. The full depth stations included a test station, the 30 stations for the SR1b Drake Passage repeat section and three repeat stations south of Burdwood Bank to collect LADCP data (no bottles were taken on these).

CTD stations

Subsurface temperature and salinity measurements

Quantity: activity duration in days = 19
Description: Met and subs. underway data were collected/processed during most of the cruise.

Current profiler (eg ADCP)

Quantity: number of stations = 31
Description: Lowered ADCP data were collected during the SR1b repeat section and the test station. No data were collected until station 07 as there were problems setting up the unit but stations 02, 03 and 04 were repeated so that LADCP data were eventually collected for all but 2 of the SR1b stations.

Current profiler (eg ADCP)

Quantity: activity duration in days = 19
Description: Vessel mounted ADCP data were collected and processed during most of the cruise

Other physical oceanographic measurements

Quantity: activity duration in days = 19
Description: Navigation data (Trimble 4000, Ashtech GLONASS and ADU-2, SeaTex, Gyro, Bestnav) were collected and processed during the cruise.

Geology and geophysics

Single-beam echosounding

Quantity: activity duration in days = 19
Description: Echo-sounder data from the JCR's EA600 and EM120 were collected.

Multi-beam echosounding

Quantity: activity duration in days = 19
Description: Echo-sounder data from the JCR's EA600 and EM120 were collected.

Moorings, landers, buoys

Physical oceanography

Neutrally buoyant floats

59° 0' 0" S 55° 51' 0" W — Argo PROVOR float launched. Argo ID 64AF800.

Neutrally buoyant floats

60° 40' 0" S 54° 28' 59" W — Argo PROVOR float launched. Argo ID 5F74300.