LOGISTICS REPORT
K042: ROV Grounding Line Study of the Mackay Glacier Tongue
Antarctica New Zealand November 1991 - December 1991
K042 91-92 LOGISTICS REPORT #2
1. AIMS.
This season we had proposed to run two programmes together; 1.,vibrocorer sampling of the sea floor in Granite Harbour and 2., the study of the Mackay Glacier Tongue Grounding line with a remotely operated submersible vehicle (ROV). At the end of September we postponed the vibrocorer programme because the equipment was not ready and satisfactorily tested but received RDRC permission to continue with the ROV-grounding line study.
Mackay Glacier forms a 3 km wide, 300 m thick, "floating" glacier tongue that moves seaward at 250 ma −1 when it enters Granite Harbour, an embayment up to 900 m deep on th Victoria Land coast. The project is to observe and describe, for the first time, the ineraction between a polar glacier tongue, sediment and sea water at the detachment point (grounding line) using a remotely operated submersible vehicle (ROV).
We propose to study the subglacial delta presumbed to have formed as basal debris carried in the glacial tongue melts out. (Macpherson 1987, Alley et al. 1989). The existence of subglacial deltas and sedimentation processes requires testing to provide better models to compare with seismic data from the Antarctic continental shelf where a number of examples of delta like sedimentary bodies have been observed (Cooper et al. 1990).
1. | Determine the character and thickness of the basal debris layer in the glaciers. |
2. | Evaluate grounding line processes including debris meltout, sediment deformation, meltwater production (if any) and ground line stability. |
3. | To check if a subglacial delta exists. |
2. PLANNING.
Planning this seasons programme was more difficult than usual because of the uncertainty about the completion of the vibrocoring equipment. We were very pleased that DSIR Antarctic and RDRC understood the developmental problems with the vibrocorer and responded positively to allow us to complete the ROV part of the programme when it became clear the vibrocorer programme could not proceed this season.
We had arranged a "final decision" date with DSIR Antarctic in late September and appreciated that this was a very late date to decide on programme changes for logistic planning.
DSIR Antarctic arranged with NSF for K042 to borrow a Nodwell vehicle with Hiab crane from McMurdo station since it was not possible to air lift the equivalent NZARP vehicle this season. Early inquiries had been made by Dr Rob Dunbar to NSF for the use of the vehicle by K042 in a cooperative programme and this probably assisted DSIR's request.
Our flight date to Antarctica was put back 7 days because of the delay of the ROV cargo arriving in Christchurch from United states (see below for details). This was a sensible delay for the K042 group, however the surveyor (K191) was also delayed because his first main task was the K042 programme. In retrospect the surveyor should have carried out some of his Scott Base programme before K042 arrived.
3. Cargo
The event cargo that originated in Wellington was transported efficiently to Scott Base. The ROV cargo which originated in the United States was however delayed in reaching Christchurch. This cargo was consigned from Illinois with the shippers guarantee that it would be on a ship due to arrive in Lyttleton on 1 November, six days before K042 scheduled departure to Antarctica. The cargo was incorrectly manifested in Los Angeles and then would not have arrived in Auckland until early December. The shipping company did not admit the problem until early November when the cargo did not arrive in New Zealand. The ROV cargo was unloaded off the ship and docked in Los Angeles on 5 November then airfreighted at the shippers expense and arrived in Christchurch on 10 November.
We appreciated the flexibility and efficiency shown by DSIR Antarctic personnel to finally get our equipment to Scott Base in a situation outside our control.
The return of the ROV equipment from Scott Base to Christchurch was also delayed until late January and it was disappointing that it was not given a higher priority at Scott Base when it was ready on 9 December. Because of this planning winter field work in Alaska in March where the ROV could next be deployed was cancelled.
In the future we would hope to plan on air freighting this equipment between USA and NZ which should avoid our major freight problem this year. A more formal system to return priority equipment such as the ROV to New Zealand would also assist future programmes and should be coordinated by the Operations Manager at Scott Base.
Description | Cube | Weight | Freight Type. |
Destination Wellington | |||
Green box; scientific equipment | 1.18 m 3 | 460 kg | Air, cargo |
Green box; scientific equipment | 0.25 m 3 | = 70 kg | Sea, cargo |
1 pallet & box (LTS container equipment) | 2.0 m 3 | = 450 kg | Sea, cargo |
S4 current meter | 0.073 | 20 kg | Air, accompanied |
Laptop computer-printer (2 cases) | 0.05 | 15 kg | Air, accompanied |
Chilly bin (ROV dredge) | 0.1 | 40 kg | Air, accompanied |
Underwater camera (2 cases) | 0.1 | 20 kg | Air, accompanied |
Destination USA | |||
ROV equipment #1 crate | 1.13 | } | Air, cargo |
ROV equipment #2 crate | 1.26 | } | Air, cargo |
ROV equipment #3 crate | 1.01 | } | Air, cargo |
ROV equipment #4 crate | 0.056 | } | Air, cargo |
ROV equipment #5 crate | 0.056 | } | Air, cargo |
ROV equipment #6 crate | 0.022 | } | Air, cargo |
ROV equipment #7 grey suitcase | 0.25 | }830 kg | Air, cargo |
4. Personnel
Alex Pyne | Leader | ARC, Victoria University |
Eric Broughton | Science technician | Geophysics, Victoria University |
Ross Powell | US Scientist | Geology, Northern Illinois Unviersity |
Garth Fallon | NZARP Surveyor (K191) | Dept of Survey and Land Information |
Sean Heaphy | Field/Mechanic | DSIR Antarctic |
Dave Statham | Plant Operator | N.Z. Army |
Our group of field personnel were compatible, enthusiastic and worked well together. The success and enjoyment of the field programme is a consequence of a good field group. It was also pleasing to note that all personnel showed individual initiative when needed to get the work completed.
5. Preparations for the Field
6. Field Transport
7. Event Diary
8. Event Routes
The helo sea ice reconn flight was Invaluable when planning the vehicle route to Granite Harbour.
We had no major difficulties with the sea ice route and generally surface travel conditions were good. We crossed a crack (0.6m wide) trending east from Cape Bernacchi on route to Granite Harbour (21 November) without any problems. This crack was only 1 -2 days old and continued to widen during the 12 days we were in Granite Harbour. This crack was crossed easily about 1 km offshore off Cape Bernacchi where it split and was only 0.5 m wide on the return journey (4 December). Another crack was crossed between the north end of Dunlop Island and Cape Dunlop going to Granite Harbour (21 November). This crack had widened on our return journey but a crossing place was found and T.REX crossed successfully. The crossing poing however was not suitable for the D5 and it crossed on a better area about 4 km offshore off Dunlop Island. A crack was also present trending southeast from the Stranded Moraines and this was also crossed at a suitable site without difficulty on the journey to Blue Glacier.
The sea ice in Granite Harbour was in very good condition with the normal pattern of cracks acoused by the Mackay Glacier Tongue. The ice in the Harbour would have remained suitable for surface travel well into mid December.
We believe that it would be feasible to work on Granite Harbour sea ice well into mid December if heavy vehicles could be wintered at Cape Roberts so that they did not have to make the return journey along the coast after early December.
9. Weather
Poor weather only hindered our operation on leaving Scott Base when visibility disappeared (≈ 20 km in route) and at the McMurdo Mooring site on our return.
The weather in Granite Harbour was very good with usually clear mornings and summer cloud developing in the mid afternoon.
11. Field Equipment
i | The field clothing now available from DSIR Antarctic is very good and kept well up to date. We did find the new windproof bib trousers and jacket to be a bit stiff and the coarse material is very sticky and wet on snow. The older Fairydown material is better in this respect but the cut of the new garments are good. Gloves are still a problem especially with our sea-sea ice based programmes, where hands get wet from working in the sea. We require finger gloves that are waterproof, flexible and insulating. |
iii | We were pleased to be able to add to the NZARP 20 manday ration box with some foodstuffs from Scott Base e.g. eggs, cream, yeast for bread; bread, fresh and frozen food. Wannigan living enables us to cook this type of food easily and we would hope to be able to still get these supplies in the future. |
iv | K042 used wannigan NZI as a kitchen-messing and sleeping unit. The wannigan is well set up for up to 4 people but is a bit more difficult with our 6 event personnel. We temporarily installed a microwave oven for our period in the field because NZl lacks an oven but it would still be better to have a small LP gas combination oven-cook top installed especially for 6 people Space is very limited in the wannigan and better sort of waste handling system could be provided such as 2 or 3 plastic "kitchen tidy" bins appropriately colour coded to split burnable, non-burnable and aluminium refuge before storing outside in larger plastic drums on the cargo sledges. K042 also used the NZARP apple and sledge to set up the ROV control equipment. The apple was suitable for this purpose but its sledge is not very suitable. The sledge does not tow properly on a strop and had to be towed between heavy sledges to stop it crabing sideways. The runners are too wide for good towing and melt in to the ice when its sunny and the sledge transmitts excessive vibration into instruments in the apple so it had to be towed very slowly. |
vi | We used the NSF Nodwell vehicle (TREX) as detailed in section 6(ib) and also a 5kVA (110V, 60Hz) ONAN generator to operate the ROV. All our equipment was returned to Scott Base in good condition. The return of equipment to Scott Base field store men was generally satisfactory except that it seems that the science personnel are expected to increasingly do more of the work that was traditionally winter work for the field storeman. An example of this is the unpacking and cleaning of food boxes and airing of sleeping bags. Most event scientist personnel have a lot of work to do to clean and pack up their scientific equipment in a short time and they should not be considered free labour by Scott Base personnel during this critical time. We used the 1 day delay at Scott Base before returning to New Zealand to sort and pack redundant VUW equipment stored in University LTS container. |
12. Radio Communications
Communications were generally good this season. The Codan SSB unit installed in NZl never let us down when we were out of VHF line of site communication in Granite Harbour and in some coastal areas. The coordination between Scott Base radio operators and the operations manager was also very good and it was reassuring that the operations manager was prepared to talk directly to field parties.
13.
K042 used space in the garage to prepare the ROV equipment. This area is a far more practical workspace than the Scott Base lab for field events with large items of equipment that require assembling and testing in a warmed area.
14. Refuge Huts
The Cape Roberts Hut was used by K042 for one day (22 November) while unpacking cargo for Botany Bay. Fuel unloaded or stored at Cape Roberts on 22 November was as follows.
JP8 (209 l drums); | # A892 MT, #A894, #A90189, A8948 |
JP8 (1 × 60 l); | old drum no code. |
Mogas (209 l drums); | #A8945, #A892 |
LPG | #NZB029 |
We picked up the apple hut and sledge and used this in Granite Harbgour then returned it to Scott Base.
15. Environmental Impact.
All burnable and non burnable waste was returned to Scott Base. To help manage these wastes in the field on this type of programme plastic barrels with lids could be provided to store separated wastes on the cargo sledges.
Human waste was deposited in augered holes in the sea ice. This is the cleanest and lowest impact method as the wastes are naturally macerated and dispearsed when the sea ice melts and breaks out.