FIELD CAMPAIGN
Ridge Survey
PI: Jenny Hutchings
Aims
- Provide validation data set for ridge parameterisations.
- Estimate the shape of the ridge (both sail and keel)
- Estimate the volume of ice incorporated into ridge
Hence determine the volume of voids in ridge
- Estimate the void size indirectly by determining the size distribution of blocks incorporated into the ridge.
Method
Sail profiles will be taken by lasor mounted on EM-bird
Keel profiles will be taken with AUV multi-beam sonar.
One keel profile will be provided by divers. This profile will provide validation data for the AUV profiles, and is a back up in case the AUV
mission fails.
The area of ice incorporated in the ridge will be estimated from the divergence of the GPS station array.
The thickness of the level ice that becomes ridge will be estimated with EM-31 and EM-bird transects along the lead.
The thickness of new ice in the lead will be measured daily. We will use thermodynamic models, together with met data from the camp, to estima
te the new ice thickness at the time of ridging.
The time and duration of ridging will be estimated from GPS data and webcam time stamps.
Void size will be estimate indirectly from measurements of block size distribution.
If the lead studied is similar to other active features in the region, we will be able to use the information from this study to upscale resul
ts to the 10km and 70km scales. By assuming new ridge shape and void fraction are the same for this dynamic event throughout the region, we ca
n extropolate the volume of ice rigded in each region during the particular event.
Tasks
Week 1
- Identify active lead
- Place GPS stations along 2 sides of lead, 400m apart.
- Determine site for in-situ transects. 60m wide region orthoganol to ridge.
Mark with bin bags and stakes.
- Set up webcam to watch this site. Measure distance of camara to lead edge daily.
- Throw IABP buoy into active lead, in view of webcam.
- Survey ice thickness on two sides of lead: EM-31, EM-bird
Week 2
Hope that ridging has occured!
- Do thickness transects, placing rope through holes for dive setup.
Measure block sizes along transects. Make servel mor block size transects along length of GPS array, between GPS stations either side of lead.
- Perform EM-bird survey over ridge
- Prep site for dive
- Do 1 dive transect
- If AUV passes performace tests, run survey under ridge.
- Recover GPS stations.
- Recover web-cam.
- Clean-up
