RRS Discovery D311
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Discovery (74E3) |
| Cruise identifier | D311 |
| Cruise period | 2006-09-09 — 2006-10-05 |
| Status | Completed |
| Port of departure | Reykjavík, Iceland |
| Port of return | Reykjavík, Iceland |
| Purpose | Research |
| Objectives | The objective of the Discovery cruise D311 was to study different aspects of the Denmark Strait overflow.
The first part of the cruise concentrated on examining the water masses at the sill and the upstream conditions in the East Greenland Current and in the Iceland Sea. Two pathways of overflow water have been discovered north of the Denmark Strait. One flows along the Greenland continental slope and involves waters from the Arctic Ocean, Fram Strait and the Greenland Sea. The other runs on the northwestern Iceland shelf and apparently carries the densest overflow water. The origin of this water mass is not yet determined. Does it derive from the Iceland Sea or does it come from farther north? To resolve this question the water mass characteristics in the East Greenland Current and in the Iceland Sea will be examined by CTD observations and water sampling, involving CFCs, H3, He3, O2, O18. In addition, attempts to recover moorings with ROV have been made. The first leg ended in Reykjavik, where exchange of scientific personnel took place. After the exchange Discovery continued to the Greenland slope, where the VEINS and ASOF CTD sections were taken and the mooring array at Angmassalik recovered and redeployed. The purpose of these sections south of the sill in the Denmark Strait is to study the evolution, strength and variability of the overflow plume - how the different water masses from north of the sill mix on their way to the south, and how much and by what mechanisms ambient water is entrained into the overflow plume. To study these processes the CTD observations and the water sampling were complemented by turbulence measurements using a freefalling CTD and current meter probe. |
| Chief scientist | Detlef Quadfasel (University of Hamburg Oceanography Institute) |
| Project | ASOF |
| Cruise report |  (13.95 MB) |
| Ocean/sea areas | |
| General | North Atlantic Ocean |
| Specific | North Atlantic Ocean, Denmark Strait |
| Track charts | (0.11 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: activity duration in days = 25 Description: SEABIRD - Thermosalinograph |
| Water bottle stations | Quantity: number of stations = 88 Description: different numbers of salinity- and oxygen (H21) - samples for calibration |
| CTD stations | Quantity: number of stations = 88 Description: SEABIRD CTD+ROSETTE |
| CTD stations | Quantity: number of stations = 9 Description: Microstructure - CTD (SEABIRD) |
| Current profiler (eg ADCP) | Quantity: number of stations = 50 Description: LADCP - on CTD+ROSETTE |
| Current profiler (eg ADCP) | Quantity: activity duration in days = 25 Description: RDI - Ship ADCP |
| Chemical oceanography | |
| Other chemical oceanographic measurements | Quantity: number of stations = 37 Description: CFC, He, Tritium, O18 |
| Meteorology | |
| Routine standard measurements | Quantity: activity duration in days = 25 Description: Routine standard measurements |
| Moorings, landers, buoys | |
| Physical oceanography | |
| Current meters | 63° 28' 59" N 36° 17' 59" W — UK1-05 recovery 22.09.2006 |
| Current meters | 63° 16' 59" N 35° 52' 59" W — UK2 deployed 26.09.2006 |
| Current meters | 63° 34' 59" N 36° 39' 59" W — F12 deployed 26.09.2006 |
| Current meters | 63° 0' 59" N 40° 31' 59" W — ADCP recovery 23.09.2006 |
| Current meters | 63° 28' 59" N 36° 17' 59" W — UK1 deployed 26.09.2006 |
| Current meters | 63° 21' 59" N 36° 3' 59" W — G1 deployed 26.09.2006 |
| Current meters | 63° 16' 59" N 35° 51' 59" W — UK2-05 recovery 22.09.2006 |
| Current meters | 63° 21' 59" N 35° 3' 59" W — G1-05 recovery 22.09.2006 |
| Current meters | 63° 34' 59" N 36° 38' 59" W — F12-05 recovery 22.09.2206 |
| Current profiler (eg ADCP) | 63° 0' 59" N 40° 30' 59" W — ADCP deployed 25.09.2006 |
| Other physical oceanographic measurements | 63° 0' 0" N 40° 32' 59" W — TUBE-28 deployed 23.09.2006 |
| Other physical oceanographic measurements | 63° 0' 59" N 39° 38' 59" W — Glider deployed 25.09.2006 |
| Geology and geophysics | |
| Bottom photography | 64° 39' 59" N 23° 13' 59" W — ROV - Test |
