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The principal purpose of this year's field season was to conduct a site survey at Skinner Saddle and Gawn Ice Piedmont in the vicinity of Byrd Glacier for future ice core drilling. We accomplished a total of 185 km high resolution radar survey and identified excellent drilling locations at both sites.
The NZ ITASE programme has five objectives:
The focus of the New Zealand ITASE group is to provide information from the climate sensitive, low altitude, coastal sites. This will capture the climate signature of the troposphere, which represents a regional account on the Ross Sea climate. The ice core data are expected to provide a record of air temperature, snow accumulation, precipitation source, atmospheric circulation strength, storm frequency, sea ice variation, ocean productivity, and anthropogenic influences. The results will help to decide whether the Ross Sea region is currently cooling or warming with a longer-term prospective, taking low frequency climate variability (100 to 1000 year cycles) into account. Furthermore, proposed tele-connections such as the Amundsen Low-ENSO correlation [Bertler et al. 2004; Meyerson et al. 2002] or the Southern Hemisphere Annual Mode [Thompson and Solomon 2002] can be further constrained. The project is expected to contribute substantially to the Latitudinal Gradient Project, as it can provide a history of temperature, humidity, sea ice cover, precipitation source, atmospheric circulation, and ocean productivity along the Victoria Coast for the last 200 to 10,000 years. Furthermore, the timing and velocity of the Ross Ice Shelf retreat some 9 to 5ka years ago is still discussed controversially [Hall and Denton 2000; Steig et al. 1998; Steig et al. 2000]. The ice core locations 2 and 3 (Evans Piedmont Glacier and Mt. Erebus Saddle) are in the vicinity of planned ANDRILL coring locations (Granite Harbour and Windless Bight). The ice core records will provide a high resolution climate dataset, which serves as a reference for the younger part of marine record recovered through ANDRILL. During the 1999/2000 season mass balance measurement devices (submergence velocity method [Hamilton and Whillans 2000; Hamilton et al. 1998]) have been deployed at Victoria Lower Glacier. The device has since been revisited. The measurements show that the glacier has a slightly negative mass balance, losing around 12-15cm thickness per year. A continuation of the measurements will allow monitoring changes in the ablation intensity of the McMurdo Dry Valleys. New Zealand's future economic and social development, environmental sustainability, and infrastructural planning critically relies upon the accurate assessment of the impact of "global warming" in our sector of the planet. Future climate change is a result of both natural variability and anthropogenic influence. A joint programme between Victoria University, GNS Science, University of Maine, is investigating ice core records from New Zealand (Tasman Glacier and Mt. Ruapehu ice field). The comparison between our NZ and Antarctic ice core records will provide much needed data for the development of realistic regional climate models to predict NZ climate in the 21
ITASE-ObjectiveLatitudinal Gradient Project ObjectiveANDRILL ObjectiveLonger-Term Mass Balance ObjectiveThe Antarctic – New Zealand Connection Objectiveth Century [Mullan et al. 2001].
Application process
The application process was efficient and well documented
Communications with Antarctica New Zealand staff
Communication with Antarctica New Zealand staff was professional, timely, and effective.
Preseason information
The information received was timely and valuable
Medicals, documentation and flights to Antarctica
The information received was timely and valuable. However, I would like to note that there is a loophole in the information flow for the medical assessment. I would like to suggest that the PI of any field group will be informed by the medical advisor of any condition of a team member relevant to the field deployment, such as allergies etc. Furthermore, I would like to suggest adding to the medical questionnaire the question on how long the examining doctor has known the patient. This would help the medical advisor to evaluate how comprehensive the medical assessment might be.
Environmental Advice
The pre-season information received was timely and valuable
Other comments
The multi-season experience of many Antarctica NZ staff makes the planning process field deployment a professional and efficient process. However, I would like to note that also new staff, in particular in the management team, contributed to have made this year's planning and implementation a very efficient and positive experience.
Reception and planning for your event
The reception was well organised, friendly and efficient. The main issues of the event were promptly discussed and organised.
Availability and condition of equipment received
Upon our arrival Scott Base staff the field support team, J.Barton and D.Mahon had staged most of our field equipment in the HFC. The equipment was in good condition and suitable for our field deployment.
Antarctic Field training and any specialist training
All team members with the exception of Rhodes conducted a refresher training, which was efficient and useful. Rhodes participated the full Antarctic field training. In addition, we conducted an additional glacier travel training. The training, carried out by Davie Robinson, was excellent and catered for the specific needs of this group. Extensive crevasse extraction training, roped skidoo-travel, and management of extreme weather conditions were an important focus of the training. All members felt that the field training was very practical, helpful, and beneficial for the team. We are grateful to E. Barnes for the concept and excellent implementation of a modulised, tailored field training programme
Field party equipment 'shakedown' journey
The equipment shakedown journey was particularly useful to identify and repair minor defects in the equipment, as well as to practise and revise traverse routines. When the team deployed to Skinner Saddle, all science and field equipment was thoroughly tested and checked.
Delays at Scott Base, whatever the cause
We deployed in general on time to and between field sites, with only minor (1 day) weather delays at our move to Gawn Ice Piedmont and from Evans Piedmont Glacier. We purposely delayed our departure from Scott base to Skinner Saddle by one day as this provided the opportunity to use the DC-3 instead of Twin Otter aircrafts. However, due to delays in the DC-3 schedule we used the Twin Otter aircrafts.
Safety and Risk Management processes
The risk management process was useful.
General comments about Scott Base
The Hillary Field Centre is a well designed, practical, and much welcome improvement for field preparations. The cage system as well as the bench space along with the excellent organisation and coordination by J. Burton and D. XXX allowed a number of groups to concurrently prepare and test their science and field equipment indoors. In addition, this provided an atmosphere for scientific exchange between groups as well as exchange of practical experience between individuals. The doors to the cages are somewhat too narrow and don't allow equipment to be transferred by trolley. The new mess and lounge area is a well implemented improvement of the living quarters.
Other comments
We would like to thank Scott Base staff for their very efficient, professional, and above and beyond support with our programme!
We used two Bombardier skidoos (SWT 08 and 09) for traversing at Skinner Saddle and Gawn Ice Piedmont. These skidoos are easier to drive and to start than the older Alpine II models. Overall, the skidoos were reliable and performed well. The skidoos were well prepared and fitted with spare parts and we received professional and useful advice during field deployment via radio. A Nansen Sledge was used to carry the Ground Penetrating Radar (GPR) control units, high resolution GPS, a generator and solar panels. The sledge was in good condition and performed extremely well in both soft snow and rough terrain. Good weather conditions allowed us to conduct 150km of GPR survey lines at Skinner Saddle, while marginal weather conditions at Gawn Ice Piedmont limited our efforts to 35km. Fuel consumption of the traverse was on average 1.5L / km (or 0.66 km/L) for both skidoos together. The ratio between the front skidoo, pulling the Nansen sledge, and the trailing back skidoo was approximately 60/40%.
The field deployment by Twin Otter was again highly successful, efficient, and practical. In preparation for field deployment to a new site, we met with the pilots, discussed satellite images and digital elevation models of the site. The crew provided us with aircraft pallets which we prepacked and plastic wrapped. The landing at this both sites was smooth and unproblematic. Four flights accommodated the cargo input of our deployment. The loading and unloading of the aircraft was fast and relatively easy even for heavy equipment, such as skidoos or fuel drums. At Gawn Ice Piedmont, crevasse fields undetected in our satellite images required finding an alternative landing site. The pilots were very accommodating and also created a safe zone for us by taxing across our chosen camp site before unloading. We would like to thank the crew for their professional, practical, and friendly support.
Field deployment to Evans Piedmont and Victoria Lower Glacier was carried out with HNO. Both deployment and pickup of cargo and passengers was very professional, efficient, and safe. The extensive regional and local experience of R.McPhail is invaluable. We are grateful for the exceptional support by HNO.
We are grateful for discussions with Captain O'Hanlon of the American Tern regarding the shipment of our ice core cargo.
Weather conditions during our deployment were variable. Overall we experienced favourable weather conditions at Skinner Saddle, with only two no-work days. We experienced a strong temperature shift from initially temperatures well below −30°C to −18 °C within a week. A total of 15cm net snow accumulation occurred during the 9 days. At Gawn Ice Piedmont weather conditions were unfavourable with only 2.5 work days out of 7 on site. Low visibility, strong winds, blowing and falling snow made traversing in this glaciological active region difficult. A total of 45cm snow accumulation occurred during our stay. At Evans Piedmont and Victoria Lower Glaciers weather conditions were very good with only one day of weather-caused delays.
Automatic weather station data from Skinner Saddle from 02 to 11 November 2007.
ECW Jackets: The Tiger Angel ECW jackets performed extremely well. They are comfortable, warm, relatively light weight, and shed snow extremely well. The design and black colour was also well perceived. The two-layer system is very practical and allows the jacket to be used in cold and temperate conditions alike. The hood doesn't perform in high winds as it is not ridged enough. In addition the neck is cut too narrow and the sippers can't be closed over a neck gaiter. The sippers on arms and wrists are too narrow and don't allow for fleece or lather gloves to go underneath.
Overall, this is a very functional and the best performing ECW jacket our group has tested yet. The Canadian Goose jacket is similar in its feature. However, it doesn't shed the snow as well, and the artificial fur is trapping snow rather than shedding it. In addition, the inner jacket cannot be zipped out as in the case of the Tiger Angel jacket. In summary, we prefer and recommend the Tiger Angel jacket.
Windproof Trousers: The new Earth Sea and Sky windproof trousers are impractical. The cut is too high and too tight around the waist, limiting freedom of movement. However, the material shed the snow well. Overall, we preferred the Cactus windproof trousers, which we used last year and found to be practical, shed snow extremely well, provide good freedom of movement, and are very durable. All members of the group wore almost exclusively these trousers from October to January, regardless of weather conditions or work tasks. Despite the heavy use, they showed little or no sign of fatigue. Only during the coldest of days (~30°C) during skidoo traversing in high winds were the trousers somewhat too cold. The only complaints some group members have is, that the full length sippers catch in the material as the seam is not stiffened enough. D.Robinson had a more durable version of this trouser. However, the material was less efficient in shedding snow and hence got wet at times. For this reason, we would recommend the simpler version. Together with the Tiger Angel ECW jackets, this combination offers an excellent and weather proof outer shell.
Polarfleece Jackets: The new polarfleece Earth, Sea, and Sky fleece jackets are suitable for a narrow temperature range as they are not designed to be used in a layering system. The cut of waist and arms is too narrow to allow other layers, such as a fleece shirt to be worn underneath. In addition the neck is cut too narrow to allow for a neck-gaiter to fit inside. Furthermore, the jacket has not enough pockets to keep for example batteries warm in inside pockets. Moreover, the material did not appear as durable as previously issued fleece jackets.
Fleece Shirt: The new Earth, Sea, and Sky fleece shirt did not withstand the challenges of the field deployment. In the short time we wore the shirts, the material around shoulders thinned significantly. As with the fleece jackets, the cut is too narrow to allow a layering of clothing, such as ice breaker underwear below the fleece shirt.
Windproof Jacket: The new windproof jacket was much worn by all team members. The material is durable, comfortable, lightweight and provides good freedom of movement. However, the cut is too narrow to permit layering, eg. the fleece jacket would not fit underneath the windproof jacket. Furthermore, the jacket doesn't provide a hood, a crucial feature to keep warm in windy conditions.
Carhart Salopetts: We welcome the decision to allow Carhart trousers as ECW trousers. We feel Carharts are warmer than down-ECW trousers and remain dry longer in blowing snow conditions than their blue equivalents. While they are somewhat heavier, they are also more durable.
Polar Heaven Tent: the new polar heaven greatly improved working and living conditions in the field through significantly higher insulation, stability, and functional doors. The new floor however, is extremely slippery with snow and poses a significant risk, in particular during set-up of the tent. We used old carpet from Scott Base which not only provided a safe surface, but also provided further insulation and improved ground stability over time. The new oven heaters for the polar heaven are a good addition, however they are too large and bulky to transport (240lb). Instead, we used the VUW heater, which is smaller and lighter (60lb). In addition, the VUW heater can be connected directly to a 60L fuel drum, while the SB heater requires an additional fuel container, which increases weight and bulk. The new H-shaped chimney improved the heater performance significantly during stormy conditions and/or heavy snow fall and we would like to suggest fitting SB heaters with the similar chimney top. After some very cold nights, water in the diesel fuel froze in the hose and stopped the fuel flow to the oven. Placing the hose frequently (every few days) in a hot water bath prevents the ice built-up and improves efficiency.
Sleeping bags: We used a combined system of a synthetic outer and a down inner. The combination provided excellent thermal conditions. However, the synthetic outer layer required frequent drying or else significant ice built-up occurred and subsequent melt.
The variety and quality of food in the new bags is good and sufficient. Freeze-dry food back up for 14day additional supply is a good alternative for taking full new bags. It saves room and weight. Maybe this could replace all freeze-dry in general food bags, since freeze-dry is expensive, not much liked, and causes digestive problems for some people. Some of the items in the food boxes had gone off. E.g. most of the milk-power and nuts were not useable.
N.A.
We used a 1kV, 2kV, and a 4kV generator. All generators were well serviced and functioned without problems.
We are grateful for the Nansen sledge cockpit built by the SB carpenters which provided wind protection for the ground penetrating radar operator and equipment and improved significantly work conditions and efficiency, in particular during marginal weather conditions.
We also would like to thank the SB engineer shop to built the glycol melt head designed by Alex Pyne which allowed to us to retrieve the arrested ice core drill from Gawn Ice Piedmont.
Throughout the season, Scott Base staff was exceptionally supportive, helpful, and innovative in solving problems or accommodating special requirements of our programme.
The HF radio system was in poor condition, with loose wires, a broken antennae cable and an unsuitable battery charger. In discussion with the SB telecom, we rewired the radio, renewed the antennae cable and modified the charger. The batteries of the VHF and Iridium phones did not hold their charge in ambient temperature. In the field, the Iridium phone was reliably functional only when powered directly off the generator.
HF reception and transmission was in general good but weather dependent. VHF radio and iridium phone reception was consistently good.
SB staff were friendly and helpful during radio communication. However, insufficient training might have been the cause for inefficiencies, miscommunication, and technical problems.
The iridium phone is a valid and practical back-up to HF radio communication. We would like to suggest activating text messaging option it is less energy demanding and cheaper than phone conversations. We used for the second year a private iridium phone to receive weather updates via text messaging. This option could also be useful to receive updates of aircraft/helo flight schedules from SB and other short messages outside the normal sched times, since the phone does not have to be switched on to store incoming messages until the phone is switched on. This could make communication initiated from SB easier and less dependent on sched times.
Additional equipment taken to Scott Base
US Science facilities used
Other comments
Assistance the science technicians gave with computer / IT issues
Issues concerning public computer facilities in the Hatherton Laboratory
Other comments
Please insert or append a photograph of the installation(s) (AWS, marker, stake etc) in this report.
Our original PEE did not considered the use of ethanol and glycol to retrieve an arrested ice core drilling system. An application to amend our PEE permit to allow the use of ethanol and glycol was kindly granted by MFAT.
Note that all event leaders who hold permits for entry to an ASPA need to complete a Visit Report for each ASPA entered. Please download this form from our 'Returning to New Zealand' web page or contact Miranda Huston, the Environmental Advisor.
Unprecedented changes are occurring in the Earth's climate. 2005 and 1998 were the warmest two years in the instrumental global surface air temperature record since 1850. The global average surface temperature has increased, especially since about 1950 with 100-year trend (1906–2005) of 0.74°C ± 0.18°C (IPCC, 2007). Although the scientific evidence of global warming is now widely regarded as incontrovertible, predicting regional impacts is proving more problematic. Especially, conclusions of the Southern Hemisphere record are limited by the sparseness of available proxy data at present (Mann & Jones, 2003).
While meteorological records from instrumental and remote sensing data display the large intercontinental climate variability, the series are insufficient to infer trends or to understand the forcing, which renders prediction difficult (Jones et al., 1999; Mann & Jones, 2003). The long ice core records from the Antarctic interior and Greenland revolutionised our understanding of global climate and showed for the first time the occurrence of RCE (Rapid Climate Change Events) (for review e.g. Mayweski and White (2002)). To understand the drivers and consequences of climate change on timescales important to humans, a new focus of ice core work is now moving towards the acquisition of 'local' ice cores that overlap with and extend the instrumental records of the last 40 years back over the last several thousand years.
This has been a key motivation behind the US-led International Transantarctic Scientific Expedition (ITASE) of which New Zealand is a member. The NZ ITASE objective is to recover a series of ice cores from glaciers along a 14 degree latitudinal transect of the climatically sensitive Victoria Land coastline to establish the drivers and feedback mechanism of the Ross Sea climate variability (Bertler et al., 2004a; Bertler et al., 2004b; Bertler & 54 others, 2005; Bertler et al., 2005a; Bertler et al., 2005b; Patterson et al., 2005). Furthermore, the ice core records will provide a baseline for climate change in the region that will contribute to the NZ-led multinational Latitudinal Gradient Project as well as providing a reference record for the NZ-led ANDRILL objective to obtain a high-resolution sedimentary archive of Ross Ice Shelf stability.
The 2008/08 field season comprised objectives at Skinner Saddle (SKS), Gawn Ice Piedmont (GIP). Evans Piedmont Glacier (EPG), and Victoria Lower Glacier (VLG).
Ground penetrating radar (GPR) measurements provide an image of the internal layering of a glacier and the topography of the ice-rock interface beneath. We applied low and high frequency radar pulses (8 MHz, 35 MHz, 200MHz, and 500MHz) to map the bedrock interface and internal flow structures in the glacier. Those features are identified through reflectors that result from changes in physical and chemical properties, such as dust layers or aerosol and density variations and are thought to represent isochrones (Morse et al., 1998; Vaughan et al., 1999). The choice of antenna frequency involves a trade-off between penetration depth and mapping resolution. The control units were mounted on a Nansen Sledge, pulling transmitter and transceiver antennae. The sledge also carried high precision GPS antenna, which is tied to the temporary GPS base station deployed at the SKS and GIP camps.
Traverses totaling 150km at Skinner Saddle and 35km at Gawn Ice Piedmont have been surveyed with GPR. Excellent isochrone reflections are visible from both the bedrock/glacier interface and in the top part of the profile, which will also be used to investigate geographical and chronological accumulation changes. Further post-processing will enhance the reflectors and will correct for surface topography.
As part of the site reconnaissance we drilled a 17m and 13m deep firn core at SKS and GIP, respectively. The drilling system was kindly provided by the Alfred Wegener Institute. The initial data set from these cores allow us to calculate annual accumulation and establish transfer functions with meteorological data to establish the quality and sensitivity of the ice.
In 2004/05 we deployed an automatic weather station on EPG. The data permit the calculation of transfer functions between ice core proxies and meteorological parameters, such as temperature, precipitation, meso-scale atmospheric circulation pattern, katabatic winds, and seasonality of snow accumulation. In addition a new snow accumulation sensor and high precision snow temperature probes allow us to monitor snow accumulation rates, the potential influence of snow loss through sublimation, wind erosion or melt, and the quality of preservation of the meteorological signal in the snow. Furthermore, the data allow us to estimate the uncertainty of re-analysis data (NCEP/NCAR and ERA-40 data) in the region. In addition we set-up a new automatic weather station at Skinner Saddle for the interpretation for our planned ice cores from Skinner Saddle and Gawn Ice Piedmont.
The response time of a glacier to changes in accumulation or ablation is dependent on the size and thickness of the ice mass. In general, the response time of cold-based glaciers is positively correlated with the size of its ice mass, leading to long response times in Antarctica. For glaciers in the McMurdo Dry Valleys, with lengths on average of 5-10km and flow rates of 1 to 3 m/a, the response times are thought to range from 1,500a to 15,000a (Chinn, 1987; Chinn, 1998). Consequently, annual variations in surface elevation may only reflect changes in loss rates. As a result surface measurements of mass balance are difficult to interpret in terms of long-term mass balance (Hamilton & Whillans, 2000). This is especially the case in places like the McMurdo Dry Valleys where mass loss is thought to be predominately due to sublimation at ice cliffs and glacier surface caused by wind and solar radiation (Chinn, 1987; Chinn, 1998). For Victoria Lower Glacier (VLG), two mass balance measurements are available in the literature for 1983 and 1991 based on ice cliff characteristics and the motion of the glacier snout (Chinn, 1998). The measurements indicate that VLG was advancing 1.24m/a into Victoria Valley during this time period. However, the small number of observations (2) and the cliff's sensitivity to sublimation (contemporary surface ablation) result in a high uncertainty of longer term mass balance. To determine the longer-term mass balance of the glaciers, unaffected by annual surface variations, three 'coffee-can' or 'submergence velocity' devices (Hamilton et al., 1998; Hamilton & Whillans, 2000) were deployed at Victoria Lower Glacier in 1999/2000 and two at Evans Piedmont Glacier in 2004/05. These are annually re-measured to monitor mass balance changes.
For mapping glacier flow structures and the glacier-bedrock interface a 'GSSI SIR 3000 and GSSI SIR 10 A were used with a maximum time window of 8,000 and 10,000 ns, respectively. A 35MHz antennae-pair (Bistatic Radarteam SE-40), a 200MHz antennae-pair, and a single 500MHz antenna are pulled by a Nansen Sledge, which carries the control units. A Trimble 5700 differential, kinematic GPS, provides absolute positioning of the GPR data and allows survey of the glacier surface topography. GPR and GPS measurements are taken in kinematic mode.
During the 1999/2000 season three submergence velocity devices (Hamilton & Whillans, 2000) for mass balance measurements in the McMurdo Dry Valleys were installed. During the 2004/2005 season two submergence velocity devices have also been installed at EPG. This method is used to determine mass balance by comparing vertical velocity of a marker in firn or ice with long-term, average snow accumulation rates. The movement of the marker is the result of three motions: firn compaction, gravitational glacial flow, and changes in mass balance. High precision GPS measurements are used to determine absolute position of the tracking point during subsequent years. Trimble 5700 base station and rover unit were used to measure the absolute position of the tracking point of the mass balance devices.
The rate of thickness change H, can then be calculated using (Hamilton et al., 1998):
H=−1)m=−2yr−1)−3)−1)−1 with azimuth)
The following parameters will be measured on the obtained firn cores and snow samples:
Oxygen isotope ratios are measured using a CO Major ion concentrations are measured for cations (Na, K, Mg, Ca, NH3) using a Dionex™ Ion Chromatograph with Dionex CS12 column and 20 mM methanesulfonic acid eluent. Anion concentrations (Cl, NO Samples are analysed for trace elements and cations (Al, Ca, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, and Zn) using a Perkin-Elmer Optima 3000 XL axial inductively coupled plasma optical emission spectroscopy with a CETAC ultrasonic nebuliser (ICP-OES-USN at UMaine) and a Finnigan Thermo inductively coupled plasma mass spectrometer (ICP-MS at VUW) for all other trace elements and selected isotopic ratios. 500cm
Oxygen and Hydrogen Isotope Ratio2 dual-inlet system coupled to a Micromass Isoprime mass spectrometer at GNS Science. The sample is measured in the presence of a standard CO2 gas. Sample duplicates and standard measurements showed a precision of ±0.08‰. Samples are analysed for stable hydrogen isotope radios δD via Cr reduction with a continuous Helium flow Eurovector elemental analyser coupled to a Micromass Isoprime mass spectrometer. Sample duplicates and standard measurements showed a precision of ±0.6‰.Major Cations, Anions, and Methylsulfonate3, SO4) are measured with a Dionex AS11 column, 6.0 mM NaOH eluent. For both measurements a 0.25 mL sample loop is used. Methylsulfonate (MS) content is measured using a Dionex AS11 column with 0.1 mM NaOH eluent and a 1.60 mL sample loopTrace Elements and CationsDust concentration and mineralogy3 volume of snow/ice is filtered through Whatman quantative 2.5μm ashless filter paper. The filter is burnt in a Vulcan A-550 furnace at 500°C for 24 hours. The residue is weight with a AG204 Mettler Toledo analytical balance, and reweighed after 24hours to check for moisture absorbance during cooling. Mineralogy is determined by mounting the dust samples in glycerol gelatine for examination under an optical particles found in the dust are analysed in a JEOL 733 Electron Microprobe at VUW.
Traverses totaling 150km at Skinner Saddle and 35km at Gawn Ice Piedmont have been surveyed with GPR. The measurements allowed us to identify an excellent drilling location at Skinner Saddle with smooth bedrock topography and a glacier thickness exceeding 600m at the proposed drilling location. Excellent isochrone reflections are visible throughout the profile to below 150m, which will also be used to investigate geographical and chronological accumulation changes. The region at Gawn Ice Piedmont is glaciologically more active (see Figure 9) and marginal weather conditions limited our ability to a more comprehensive survey, as achieved at Skinner Saddle. However, we identified a suitable drilling site with a undisturbed depth of at least 300m, which is deeper than the target depth of 200m for this site. Further post-processing will enhance the reflectors and will correct for surface topography.
These images are used to create 3D model of bedrock topography (Fig.10) and/or individual isochrones to establish ice flow direction and shear stresses as well as geographical and temporal snow accumulation changes. This allows a comprehensive assessment of the suitability of the proposed drill site.
The automatic weather station at SKS is operational since 01 Nov 2007. The recorded data for pressure, solar irradiation, air temperature, snow temperature, dew point, and snow accumulation for the time period of our deployment at SKS are shown in Fig.11.
Our weather station at EPG has been operational since October 2004. The current data set is shown in Fig. 12. The lack of data during winter 2005 is due to a technical failure.
A shallow snow pit was investigated at VLG while we waited for our GPS mass balance measurements to be completed. The large seasonal temperature changes characteristic for this area produces some of the largest hoar (or cup) crystals on the planet.
Our preceding research – Holocene Climate History from Coastal Ice – has identified the value of the specific characteristics of ice core records from coastal, low altitude sites (Bertler et al., 2004a; Bertler et al., 2004b; Bertler & 54 others, 2005; Bertler et al., 2005a; Bertler et al., 2005b; Mayewski et al., 2005; Patterson et al., 2005; Bertler et al., 2006a; Bertler et al., 2006b) and showed how tropical phenomena, such as ENSO have a significant influence on the Ross Sea Region. In contrast to Antarctica's interior, which is influenced by temperature inversion and climatic cooling of the stratosphere, the coastal sites are dominated by cyclonic activity, and hence by the climate of the lower troposphere (King & Turner, 1997). As a result, coastal sites are especially climate sensitive and show potential to archive local, rapid climate change events that are subdued or lost in the 'global' inland ice core records, such as Vostok. The reconnaissance work successfully identified two suitable drilling locations to provide such data.
We are grateful for the loan of the Alfred Wegener Institute (Germany) shallow firn drill. Futhermore, Prof. P. Kyle (USA) is providing 8 shallow firn cores from Mt Erebus, complementing our intermediate depth ice core from Mt Erebus Saddle. This will allow us to investigate in collaboration with Prof. P. Kyle volcanic history of Mt Erebus over the last hundred years or so.
We would like to thank Antarctica New Zealand staff based in Christchurch and Scott Base for their dedicated and innovative support with our project, in particular E. Barnes, I. Miller, D. Peterson, Neil Gilbert, and P. Woodgate, and at Scott Base S.Trotter, K. Rigarlsford, J. Burton, D. Mahon, D. Miller, G. McElroy. We would like to thank ScanTec, especially Matt Watson for excellent ground penetrating radar surveys. We would like to thank Kenn Borek Twin Otter crews for their professional, practical, and friendly approach and attitude. We are indebt to Helicopter NZ staff, in particular Rob McPhearson, for his . We would like to thank the National Isotope Centre, GNS Science, Ms Valerie Claymore, the Geochemical Laboratory, Victoria University, Prof. Joel Baker, and the Climate Change Institute, University of Maine, Prof. Paul Mayewski for ice core analyses. We are indebt to the Alfred Wegener Institute for lending us the shallow firn drilling system. This project is funded by Victoria University of Wellington, GNS Science, and Foundation for Research, Science, and Technology (Grant No. VICX0704 and CO5X0202).
To date, aerosol deposited trace element records have been poorly utilised in ice core research. They can however provide important tracers or proxies of atmospheric (e.g. regional circulation, moisture transport and precipitation) and oceanic (sea-ice extent and variability) processes. In conjunction with more traditional ice core analyses (isotopic and major ion variations), new knowledge of their past variability will allow an improved understanding of the Ross Sea climate system. This has the potential to provide information that can be related to the larger Antarctic atmospheric circulation systems; the El Nino Southern Oscillation (ENSO) 1, Southern Annular Mode (SAM) 2 and to a lesser degree the Antarctic Circumpolar Wave 1, whose relative importance remain controversial.
For this purpose, two coastal sampling sites have been chosen with variable climatic and sea ice cover influences. Whitehall Glacier, Northern Victoria Land coast was sampled in 2006/07 and provides an area of frequent and intense cyclonic activity due to its proximity to the Southern Ocean and Antarctic low pressure belt 1,3. This will be used in comparison of the predominantly katabatic controlled climate of Evans Piedmont Glacier that has been sampled in the most recent 2007/08 season 4.
This work contributes to the Antarctica NZ Scientific Strategy in the following sections:
This project seeks to understand the relationship between atmospheric circulation and aerosol deposition in the recent instrumental record with the potential to extrapolate it back further into the ice core record. Southern Ocean Research and Antarctic Ecosystems Research all require a greater understanding of the climatic context conducted due to ecosystem dependency on climatic conditions.
1C-1 What does the detailed (annual –decadal) regional climate record from ice-cores along Victoria Land Coast over the last 10,000 years tell us about patterns of climate behaviour in the region and linkages with the Southern Hemisphere climate patterns?52C -1 – What drives natural seasonal and inter-annual variability in coastal ecosystems in the Ross Sea?5
Clean snow sampling at Evans Piedmont Glacier
A primary objective of 2007/08 field season was to sample a high resolution snow record of the last decade, with emphasis on ultra-cleanliness, as concentration levels of trace elements in polar snow and ice are in the parts per trillion (ppt) to parts per quadrillion (ppq) range 6.
Automatic Weather Station data retrieval, Evans Piedmont Glacier
An automatic weather station (AWS) was installed by K049 in 2004/05 near the previous drill site and current sampling site. This data is important in establishing transfer functions between temporal variations in snow chemistry and meteorological parameters in order to quantitatively establish the use of trace elements as a climatic proxy.
A 4m deep snow profile was sampled at 1cm resolution using ultra clean snow sampling methodology in order to maximise the array of potential measurable trace elements. These will include Al, As, Ba, Be, Cr, Co, Fe, Li, Mn, P, Rb, Sr, Ti, U, V, Zn. Isotopic (δ18O and δD) and major ion composition will also be measured.
All sampling vials, 60ml Nalgene HDPE (high density polythene), were pre-cleaned following the procedure of Osterberg et al6. Preparation includes soaking in 5% trace metal-grade HNO3 for 1 week, triple rinse in DI (deionised, 18 MΩ) water and again soaked in DI H2O. Sampling equipment was triple rinsed, soaked for 4 weeks and triple rinsed again in DI water.
The sampling surface was pre-cleaned using a clean metal spade and the removal of at least 20cm horizontally immediately prior to sampling with a ceramic (ZrO) knife. 1cm thick samples were cut horizontally across the snow into a HDPE tray and transferred into vials. Tyvek clean suits, facemasks and dust free polyethylene gloves were worn to prevent sample contamination from personnel.
Density and temperature profiling was conducted at 5cm resolution once sampling was complete and the surface was freshly cut back. Cylinders of known volume were hammered into the fresh surface, filled, extracted and weighed to determine precise density measurements.
Physical description notes of crystal structure and the location of hoar horizons are used to provide a preliminary chronology. This was taken both during and after sampling, with the upper section constructed into a thin wall to determine these more clearly (Fig 3.) Stable isotope and chemical species characterised by seasonal changes (e.g. sea salt species Na, Sr) will be used to confirm this chronology.
Wind speed and direction, air temperature, snow accumulation and temperature, barometric pressure, humidity, and solar radiation are recorded (Fig.2).
The presence of summer hoar horizons and changes in density suggests that the 4m pit represents 13 years of accumulation.
The weather station has recorded data from the 15th Nov 2004 through to collection on the 3/12/2007. A problem with storage limits prevented continual data throughout 2005, but this was addressed by K049 during 2005/06 season. The record from Nov 2004 to Dec 2007 for air temperature, snow depth (i.e. accumulation changes), solar radiation, pressure and snow temperature is shown below (Fig. 4).
This data will contribute to the NZ ITASE current research – Holocene Climate History from Coastal Ice - by providing new knowledge on the seasonal pattern of aerosol deposited trace elements in snow. The investigation will include determining the patterns of seasonal aerosol concentrations and their sources and sinks through correlation with both site specific meteorological data and regional re-analysis data. This will assist in the interpretation of deeper ice core trace element records and our understanding of the Ross Sea tropospheric circulation system in the past.
We would like to thank all who have been involved in this project - the very enthusiastic and helpful Antarctica New Zealand Staff at both Christchurch and Scott Base; New Zealand Post for their support of the Antarctica New Zealand Postgraduate Award; Helicopter NZ staff, in particular Rob McPhearson; and those who were unlucky enough to be in the field when pit digging was underway, Jody Burton and Billy Wallace. This would also not be possible without the colaboration of staff at the Climate Change Center, University of Maine and National Isotope Center, GNS, Wellington, in particular Valerie Claymore. This project is supported by Victoria University of Wellington, Geological and Nuclear Sciences, and FRST (VUWX0704 and C05X0202 grants).