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Immediate report of Victoria University of Wellington Antarctic Expedition 1988-89: VUWAE 33
ANTARCTIC BOTTOM CURRENTS (K042)
ANTARCTIC BOTTOM CURRENTS (K042)
Aims
This season's program was designed to test if density driven bottom currents originate from beneath the Mackay Glacier Tongue in Granite Harbor. A single current meter/sediment trap mooring would be set for about two months (November – January) at the snout of the Mackay Glacier Tongue. Last season (1987-88) a 14 hour deployment at this site recorded low velocity (<10 cm/s) flows which exhibit progressive changes in direction and duration that appear to be related to the diurnal tide cycle. A tide gauge will also be established at Cape Roberts initially to record the tide cycle during the period of the current meter deployment and if successful remain to continue recording during the following year.
Personnel
| Alex R. Pyne (Leader) | Antarctic Research Centre |
| Victoria University of | |
| Tom Perrett | WELLINGTON. |
Preparations for the Field
November 1988
Tom Perrett arrived four days before Pyne at Scott Base and during this time had completed his survival course and prepared about half of the field equipment required. Some cargo including fuel had already been transported to Cape Roberts in mid October. Vehicles were not available until the day after Pyne arrived on 4 November.
Preparations for this event were handled promptly and efficiently by the OIC and his staff at Scott Base and we were able to depart for the field 3 days after Pyne's arrival. Equipment was stored at Cape Roberts for the return part of the field work in January 1989.
The January part of our field work was also handled efficiently from Scott Base enabling our event to fly to Granite Harbor the day after arrival at Scott Base.
Field Transport
NZARP Vehicles
Event K042 was allocated a "half track" all seasons vehicle (ASV)#21. This vehicle performed very well with no major problems or breakdowns. It is a relatively light vehicle and we were careful not to overload it although we carried a maximum load in the newly built box sledge most of the time. The new box sledge is a very useful compliment to the ASV although the tray is high and slopes towards the front when attached to the ASV draw bar. This is particularly annoying when lifting some of our very heavy equipment into it, e.g. winch (550 lb).
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| Location | Add. | Mogas (l) Tot. (l) | Running hrs. | Read. Tot. | ASV Speedo (km) Read. (km) | Tot. | Map (km) distance | Comments |
|---|---|---|---|---|---|---|---|---|
| Scott Base | 68 | 271 | 1508 | Greased | ||||
| Dirty Ice | 36 | |||||||
| Butter Pt. | 41 | 1.5 | Glycol mix | |||||
| Gneiss Pt. | 51 | |||||||
| Debenham Gl. | 20 | 216 | ||||||
| C. Roberts | 216 | 286.8 | 15.8 | 1645 | 137 | 150 | Greased | |
| Granite | ||||||||
| Harbor area | 309.8 | 23.0 | 1797 | 152 | Glycol mix dripping on track when stopped. Greased. | |||
| C. Roberts | 68 | 309.8 | 1797 | 0.25 | Engine oil | |||
| Gneiss Pt. | 55 | 123 | ||||||
| Butter Pt. | 50 | 173 | ||||||
| Dirty Ice | 40 | 213 | ||||||
| Scott Base | 323.7 | 13.9 | 1940 | 143 | 150 |
Analysis of the above vehicle log shows that fuel consumption should be calculated at about 13l per 10 km. The radiator overflow system did not seem to work correctly and coolant leaked out of the overflow tank although there was little loss from the radiator itself. The dip stick in the hydraulic tank is also unmarked so it is difficult to establish the correct level in this tank.
The ASV does not perform well in very soft snow (e.g. snow drifts) and we spent several hours digging out on one occasion.
Recommendations
| (i) | A small portable electric winch should be mounted on the front of the ASV to extract it from soft snow. |
| (ii) | The hydraulic tank dip stick should be marked to enable measurement of the correct fluid level. |
| (iii) | The box sledge should be modified or have an add on draw bar section to level the sledge tray when towed with on ASV. The ski stop chains also require pinned shackles so that they don't come undone by travel vibration. |
| (iv) | A one page check list for the ASV would be especially useful for those who have not used the vehicles before. Rates of usage of fuel, oil, hydraulic oil, greasing should be shown. A copy of the check list should be kept with the vehicle. |
| (v) | Small plastic containers, 5 & 10 versions of the red mogas containers, should be available for oils, coolant and premix fuel for small motors e.g. chainsaws and augers. |
| (vi) | The ASV speedo is inaccurate as shown in the vehicle log. We need a method of measuring distance for bathymetry transects. The present electronic speedo should be recalibrated or a new one fitted that will read tenths of a kilometre. |
Helicopter Operations
| Date | Mission Details | Hours (est) |
|---|---|---|
| 6 Jan. | Scott Base to Cape Roberts (3 pax + 500 lb internal, pick up sling @ Marble Pt. Shut down @ C. Roberts to make up undersling load (1,000 lbs.) | 0.5 hrs |
| Cape Roberts to Mackay Glacier (3 pax + camp) | 0.5 hrs | |
| Mackay Gl., to C. Roberts, to Mackay Glacier (sling load, 1,000 lbs.) | 2.5 hrs | |
| 7 Jan. | Mackay Glacier, to Cape Roberts (3 pax + camp + equipment; 900 lbs.) C. Roberts, to Mackay Gl., to Scott Base (sling load, 800 lbs.) | 2.0 hrs |
| 9 Jan. | Cape Roberts, to Scott Base (3 pax + camp; 500 lbs.) | 1.5 hrs |
| Total: 6 hours |
This operation went smoothly and was efficiently programmed from Scott Base. The helo was not able to lift both our internal load and the sling load from Cape Roberts so an extra 20 minute shuttle was required.
Event Diary
| 31 Oct. | Perrett to Scott Base. |
| 1-2 Nov. | Perrett - Survival Course. |
| 2-4 Nov. | Perrett - equipment preparation. |
| 4 Nov. | Pyne to Scott Base |
| 5-6 Nov. | Preparation of vehicle & equipment |
| 7 Nov. | 1330 hrs. Left Scott for Butter Pt. Meet S-216 at the Dirty Ice. 2230 hrs, arrive Butter Pt., slept in hut. S-216 camp nearby. |
| 8 Nov. | 1030 hrs. Left Butter Pt., refuelled at Gneiss Pt. fuel cache 1930 hrs arrive C. Roberts. Slow travel on multi year ice in Marble Pt. bay and second year ice Gneiss Pt. to Dunlop Island. |
| 9 Nov. | Unpack equipment, inspect possible tide gauge sites, vehicle service curtailed by blowing snow. |
| 10 Nov. | To Mackay Glacier tongue. Bathymetry survey for mooring site. Return to C. Roberts. |
| 11 Nov. | Check & prepare equipment for test mooring at C. Roberts. |
| 12 Nov. | To Mackay Gl. Deploy S4 test mooring (5 hours to lower). Overnight with S-216 at Mackay Gl.page 29 |
| 13 Nov. | Check mooring, return to C. Roberts. Drilled ice foot at C. Roberts for tide gauge with K191 assistance. |
| 14 Nov. | To Mackay Gl. Recover S4 and redeploy with 8 sediment traps in mooring. 9.5 hours to recover & redeploy. Overnight near Cuff Cape with S-216 & K191. |
| 15 Nov. | Return to C. Roberts. Began assembly of tide gauge components. |
| 16 Nov. | Cut ice foot hole with chainsaw assisted by K191. Fitted transducer pipe to shore rock face. |
| 17 Nov. | Erected tide gauge frame with solar panel, data logger & battery. |
| 18 Nov. | Programmed and levelled tide gauge with K-191. Began packing equipment and prepared equipment for recovery of mooring in January. |
| 19 Nov. | Pack up for return to Scott Base. Checked tide gauge and reprogrammed after changing power fuses. 1530 hrs left C. Roberts, refuelled @ Gneiss Pt. and picked up 44 gal. Mogas drum. Stuck for 2 hours in soft snow drift near ice bergs between Gneiss Pt. & Marble Pt. 2430 hrs arrived Butter Pt. Slept in hut. |
| 20 Nov. | 1130 hrs left Butter Pt., arrived Scott Base 1615 hrs. |
| 21 Nov. | Pack equipment preparation for January return. Pyne to Christchurch, evening DV flight. |
| 23 Nov. | Perrett to Christchurch. |
| 3 Jan. | Pyne, Perrett Christchurch - Christchurch (8 hours). |
| 4 Jan. | Pyne, Perrett Christchurch - Christchurch (7 hours). |
| 5 Jan. | Pyne, Perrett to Scott Base. |
| 6 Jan. | 1600 hrs. Pyne, Perrett, Sole (K191) Scott Base to Mackay Glacier. 1/2 hour shutdown @ C. Roberts to make up sling load. Recovered mooring in evening (7 hours to establish equipment, recover mooring, pack equipment). |
| 7 Jan. | Transfer from Mackay Glacier to C. Roberts. Undersling load returned to Scott Base. Downloaded tide gauge data and levelled to recalibrate. |
| 8 Jan. | Installed new power protection for tide gauge, down loaded new winter program and relevelled. |
| 9 Jan. | Recheck & level tide gauge. Pack for helo. Return to Scott Base @ 1730. |
| 10-11 Jan. | Pack up equipment for return to NZ. |
| Pyne, Perrett to Christchurch. |
Field Equipment
The quality and serviceability of NZARP field equipment is improved each year, although sometimes changes seem to slow. The following comments and suggestions are intended to help plan for the future.
Recommendations
| (i) | Insulated plastic containers of about 20 litres capacity (wide mouth "IGLOO") to store a water supply required for some field parties. |
| (ii) | Field parties be supplied with updated information additional to the field manual concerning year by year changes in field supplies e.g. new items of field food etc. The field food system is now more flexible and caters better for individual tastes but it is necessary to know exactly what is available. |
| (iii) | Frozen food lines could be expanded to include potato products e.g. oven chips as an alternative to plastic spud or rice. Brown rice should also be added to the field food stocks. |
| (iv) | There should be some empty food boxes available for frozen foods and for those events who find it more efficient to pack food boxes themselves. Frozen food boxes could be insulated, or painted a different colour (e.g. white) to reflect the suns heat. |
Radio Communications
VHF hand held radios with high gain aerials were used most of the time by K042. We mounted a high gain aerial on the Cape Roberts hut working the Mt. Newall repeater to Scott Base while this hut was in use. In January while at the Mackay Glacier Tongue we tried to use the repeater on the flank of Mt. Erebus with a VHF high gain. Communication was established with Scott Base but it was intermittent, especially when receiving Scott Base. This may be due to the low power output of this repeater. HF communication was also used on occasion while in Granite Harbor, but this was also erratic and certainly less convenient.
Recommendations
| (i) | A temporary or permanent repeater should be established on Mt England to service the Granite Harbor area with VHF communications. |
Refuge Huts
The Cape Roberts hut was used as a base for work in Granite Harbour. The hut was adequate for our programme this season but could be improved if future work in this area justifies the improvements. Cape Roberts is a small skua nesting area and any larger establishment will have to take this into consideration.
Future buildings could be sited on the higher north side of the flat area because this lower area becomes wet with ponds during high summer.
The present hut should have new kitchen utensils provided because many of the old utensils were from an older kitchen box and are now unserviceable.
Several empty drums with unknown contents should be moved from C. Roberts when the next transport opportunity arises.
Acknowledgements
This season's program went very smoothly and we thank the staff of Antarctic Division and all the staff at Scott Base for efficiently implementing our field program. We are especially grateful to John Alexander (Scott Base Operations Manager) the Scott Base mechanics, Store Personnel, Garth Varcoe and his group who moved some of our equipment to Cape Roberts early in the season.
NZARP Surveyors Garth Falloon and Pat Sole provided invaluable survey assistance and helped establish the Cape Roberts tide gauge.
The VUW Mechanical Workshop maintained and built new equipment for this program which included the tide gauge frame and mooring recovery equipment. Eric Broughton (VUW RSES) and Peter Issacs (NZ Meteorological Office), helped with the development and programming of the tide gauge and NZ Oceanographic Institute (DSIR) maintained the S4 current meter.