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Victoria University Antarctic Research Expedition Science and Logistics Reports 2006-07: VUWAE 51
*AIMS
*AIMS
Seven key locations were identified for the NZ ITASE (International Transantarctic Scientific Expedition) programme. The analyses on the ice core from the first site, Victoria Lower Glacier in the McMurdo Dry Valleys, have been completed. During the 2003/04 field season we carried out a detailed reconnaissance of sites 2 and 3: Evans Piedmont Glacier (EPG) and Mt Erebus Saddle (MES) and determined the most suitable locations of the ice core recovery. During the 2004/05 field season we recovered to intermediate length ice cores (180m and 200m, respectively) from these locations and conduct further in-situ measurements, such as borehole temperature and light penetration characteristics, snow density and stratigraphy and its geographical variability. Furthermore, we installed a weather station and mass balance devices at EPG and cased the borehole at MES for future measurements. During the 2005/06 field season we re-visited VLG and EPG to conduct GPS measurements of the submerge velocity devices and to sample shallow snow pits. Furthermore, we retrieved the meteorological data and carried out maintenance work on the automatic weather station at EPG. Lastly we deployed 6m snow stakes at the high accumulation site at Mt Erebus Saddle. During the 2006/07 season we conducted a field survey at Whitehall Glacier and recovered a 100m deep ice core and recovered another 180m deep ice core from Mt Erebus. In addition we revisited VLG and EPG for mass balance measurements and automatic weather station maintenance as in the previous year.
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ITASE-Objective
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.
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Latitudinal Gradient Project Objective
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].
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ANDRILL Objective
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.
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Longer-Term Mass Balance Objective
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.
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The Antarctic – New Zealand Connection Objective
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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 IGNS, University of Maine, Victoria University 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 21th Century [Mullan et al. 2001].
