Cruise inventory

RRS Challenger CH146

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Challenger (74CH)
Cruise identifierCH146
Cruise period1999-08-17 — 1999-08-27
StatusCompleted
Port of departureSouthampton, United Kingdom
Port of returnSouthampton, United Kingdom
PurposeResearch
ObjectivesA single cruise for the deployment of Autosub AUV in the southern North Sea. Autosub was deployed to survey across the Broken Bank (two main transects). It was equipped with turbulence and current sensors.
Main objective:
To measure the spatial variation of flow and turbulence over the sand bank and examine the tidal flow rectification due to topography.
Main tasks:
1) Deployment recovery of Autosub AUV;
2) Deployment-recovery of a bottom benthic boundary layer tripod, two pressure gauges, a bottom mounted ADCP;
3) CTD casts;
4) Side-scan sonar survey;
5) Sea bed sampling.
Chief scientistGeorge Voulgaris (University of South Carolina Department of Earth and Ocean Sciences)
ProjectAutosub Science Missions Thematic Programme
Coordinating bodyNERC - Autosub Programme Manager, SOC
Cruise reportRRS Challenger CH146 cruise report ch146.pdf — access key 'C' (0.67 MB) 
Ocean/sea areas 
GeneralNorth Sea
SpecificBroken Bank - Norfolk Banks area
Track chartsRRS Challenger CH146 cruise track — trk4391.html
Measurements 
Physical oceanography 
CTD stationsQuantity: number of profiles = 28
Description: CTD casts - 13 stations on August 10, 1999, 15 stations on August 23, 1999. (Using Falmouth Sci. Inc. MCTD-MBP-D).
Geology and geophysics 
GrabQuantity: number of samples = 14
Description: Seabed surface sediment samples, using a Van-veen grab.
Long/short range side scan sonarQuantity: track kilometres = 50
Description: Sid-scan survey lines using a dual frequency (114 and 414 KHz) Geoacoustics side-scan sonar. Transects were across Broken Bank. Majority of transects over the same tracks trying to identify bedform movement.
Moorings, landers, buoys 
Physical oceanography 
Transparency (eg transmissometer)53° 17' 59" N  2° 12' 0" E — Tripod with 3 cm current meters at 172, 143 and 81 cm above bed, 3-D currents using ADV at 27 cm above bed, pressure (depth and waves), 3 optical backscatter sensors (OBS) at 213, 105 and 52 cm above bed, LISST-100 (particle size analyser 1 um to 250 um) at 205 cm, temperature and conductivity, altimeter. Period of deployment 19-25 August 1999. Depth = 14 m.
Current meters53° 17' 59" N  2° 12' 0" E — Tripod with 3 cm current meters at 172, 143 and 81 cm above bed, 3-D currents using ADV at 27 cm above bed, pressure (depth and waves), 3 optical backscatter sensors (OBS) at 213, 105 and 52 cm above bed, LISST-100 (particle size analyser 1 um to 250 um) at 205 cm, temperature and conductivity, altimeter. Period of deployment 19-25 August 1999. Depth = 14 m.
Current profiler (eg ADCP)53° 15' 59" N  2° 4' 59" E — Upward looking ADCP (broadband) 1600 KHz pressure gauge. Both bottom mounted. Period 19-25 August 1999. Mean depth = 35m. Sampling every 3 min.
Sea level (inc. bot. press., inverted echosounder)53° 21' 0" N  2° 4' 59" E — Pressure gauge, bottom mounted. Period 19-25 August 1999. Mean depth = 14 m. Sampling every 3 min.
Sea level (inc. bot. press., inverted echosounder)53° 15' 59" N  2° 4' 59" E — Upward looking ADCP (broadband) 1600 KHz pressure gauge. Both bottom mounted. Period 19-25 August 1999. Mean depth = 35m. Sampling every 3 min.
Sea level (inc. bot. press., inverted echosounder)53° 17' 59" N  2° 12' 0" E — Tripod with 3 cm current meters at 172, 143 and 81 cm above bed, 3-D currents using ADV at 27 cm above bed, pressure (depth and waves), 3 optical backscatter sensors (OBS) at 213, 105 and 52 cm above bed, LISST-100 (particle size analyser 1 um to 250 um) at 205 cm, temperature and conductivity, altimeter. Period of deployment 19-25 August 1999. Depth = 14 m.
Instrumented wave measurements53° 17' 59" N  2° 12' 0" E — Tripod with 3 cm current meters at 172, 143 and 81 cm above bed, 3-D currents using ADV at 27 cm above bed, pressure (depth and waves), 3 optical backscatter sensors (OBS) at 213, 105 and 52 cm above bed, LISST-100 (particle size analyser 1 um to 250 um) at 205 cm, temperature and conductivity, altimeter. Period of deployment 19-25 August 1999. Depth = 14 m.
Other physical oceanographic measurements53° 17' 59" N  2° 12' 0" E — Tripod with 3 cm current meters at 172, 143 and 81 cm above bed, 3-D currents using ADV at 27 cm above bed, pressure (depth and waves), 3 optical backscatter sensors (OBS) at 213, 105 and 52 cm above bed, LISST-100 (particle size analyser 1 um to 250 um) at 205 cm, temperature and conductivity, altimeter. Period of deployment 19-25 August 1999. Depth = 14 m.