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Victoria University Antarctic Research Expedition Science and Logistics Reports 2008-09: VUWAE 53


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Antarctica New Zealand 2008/09

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1. Scientific Programme

This section should short and concise. The information you provide will be used for post-season publications such as Antarctica New Zealand's annual report, media releases and other information documents, so that we can give informed coverage of your science. As a result, the audience is likely to be largely non-scientists so we ask that you present your submission in an easy to read 'laymans' style.

a. Context of research in terms of the contribution to scientific knowledge and to the Science Strategy and the relevance of the research

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.

b. Research objectives

Automatic weather station set-up, maintenance, and data retrieval

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.

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Fig.1: Automatic weather station at Skinner Saddle after excavation (left image) and before

Fig.1: Automatic weather station at Skinner Saddle after excavation (left image) and before

Submergence Velocity Measurements at Victoria Lower and Evans Piedmont Glacier

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.

Fig.2: Submergence Velocity Measurements at VLG

Fig.2: Submergence Velocity Measurements at VLG

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Drilling of five shallow firn cores from Windless Bight / McMurdo Ice Shelf

To determine dust flux through the McMurdo Ice Shelf and onto the seabed beneath, a series of shallow firn cores were recovered from the Windless Bight area. This region was chosen as a previously collected 20m firn core showed distinct dust layers that are dateable to the large storm events in the area, such as the winter storm of 2004. The shallow 3m cores are expected to contain the 2004 storm and will allow quantification of the amount of dust deposited during the storm in the region.

Fig.3: Firn core drilling along Black Island Road

Fig.3: Firn core drilling along Black Island Road

c. Preliminary results and discussions

Both weather stations at Evans Piedmont Glacier (EPG) and Skinner Saddle (SKS) were operational and collected data over the last season. Below the data are shown.

Our weather data show that over the past year snow accumulation at the two sites varied. EPG received a total of 50cm snow, predominantly during the summer period. SKS received a total of 1.60m snow accumulation, precipitating throughout the year. Our data suggest that both sites have above average snow accumulation making them high resolution climate recorders.

Fig. 4: AWS data recovered this year from Evans Piedmont Glacier

Fig. 4: AWS data recovered this year from Evans Piedmont Glacier

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Maximum summer temperature at EPG and SKS reached +12°C and +5°C, respectively. Minimum winter temperature at EPG and SKS reached −42°C and −45°C, respectively. At both sites battery voltage never dropped below 12V, despite the solar panel being buried at SKS for the crucial spring period.

Fig.5: AWS data recovered this year from Skinner Saddle. The spiky, high snow accumulation data peaks indicate times when the snow sensor was ice covered. For reconstructing true snow accumulation, minimum base line is used.

Fig.5: AWS data recovered this year from Skinner Saddle. The spiky, high snow accumulation data peaks indicate times when the snow sensor was ice covered. For reconstructing true snow accumulation, minimum base line is used.

2. Publications

As part of the measurement of research outputs that we are now undertaking, it is important that all your publications for the past year are included as these will be used for searching the Web of Science for citation data. Note that reprints of any publications resulting from work supported by Antarctica New Zealand are to be forwarded to the Science Advisor at Antarctica New Zealand. These are kept in a reprint collection for reference, recorded in our bibliography (available on the web), and titles are submitted to the Cold Regions Bibliography Project (www.coldregions.org/).

a. Publications since your last Antarctic season

P. A. Mayewski, M. P. Meredith, C. P. Summerhayes, J. Turner, A. Worby, P. J. Barrett, G. Casassa, N. A. N. Bertler, T. Bracegirdle, A. C. Naveira Garabato, D. Bromwich, H. Campbell, G. H. Hamilton, W. B. Lyons, K. A. Maasch, S. Aoki, C. Xiao, and Tas van Ommen: State of the Antarctic and Southern Ocean climate System (SASOCS): Reviews of Geophysics, doi:10.1029/2007RG000231, in press

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b. Planned publications

N.A.N. Bertler, Naish, T.R., and Mayewski, P.A.: "A 150-year reconstruction of the Southern Annular Mode"

Rhodes, R., Bertler, N.A.N., Baker, J., Sneed S.B., and Oerter, H.: "Effects of large icebergs on sea-ice and primary productivity in the Ross Sea Region

Bull, J.R., Bertler, N.A.N., Baker, J.A.: Ice core signal preservation of atmospheric circulation changes in Victoria Land, Antarctica, over the last 50 years

c. Cited References

Bertler, N.A.N., & 54 others. 2005. Antarctic Snow Chemistry. Annals of Glaciology, 41, 167-179.

Bertler, N.A.N., Barrett, P.J., Mayewski, P.A., Fogt, R.L., Kreutz, K.J., & Shulmeister, J. 2004a. El Niño suppresses Antarctic warming. Geophysical Research Letters, 31(L15207, doi:10.1029/2004GL020749).

Bertler, N.A.N., Barrett, P.J., Mayewski, P.A., Sneed, S.B., Naish, T.R., & Morgenstern, U. 2005a. Solar forcing recorded by aerosol concentrations in coastal Antarctic glacier ice, McMurdo Dry Valleys. Annals of Glaciology, 41, 52-56.

Bertler, N.A.N., Mayewski, P.A., Barrett, P.J., Sneed, S.B., Handley, M.J., & Kreutz, K.J. 2004b. Monsoonal circulation of the McMurdo Dry Valleys-Signal from the snow chemistry. Annals of Glaciology, 39, 139-145.

Bertler, N.A.N., Naish, T.R., Mayewski, P.A., & Barrett, P.J. 2005b. Opposing oceanic and atmospheric ENSO influences on the Ross Sea Region, Antarctica. Advances in Geoscience, 6, 83-86, SRef-ID:1680-7359/adgeo/2006-1686-1683.

Bertler, N.A.N., Naish, T.R., Mayewski, P.A., & Barrett, P.J. 2006a. Opposing oceanic and atmospheric ENSO influences on the Ross Sea Region, Antarctica. Advances in Geoscience, 6, 83-86, SRef-ID:1680-7359/adgeo/2006-1686-1683.

Bertler, N.A.N., Naish, T.R., Oerter, H., Kipfstuhl, S., Barrett, P.J., Mayewski, P.A., & Kreutz, K.J. 2006b. The effects of joint ENSO-Antarctic Oscillation forcing on the McMurdo Dry Valleys, Antarctica. Antarctic Science, 18(4), 507-514.

Broecker, W.S. 2000. Abrupt climate change: causal constraints provided by the paleoclimate record. Earth-Science Reviews, 51,137-154.

Broecker, W.S. 2003. Does the trigger for abrupt climate change reside in the ocean or in the atmosphere? Science, 300, 1519-1522.

Bromwich, D.H. 1988. Snowfall in the high southern latitude. Reviews of Geophysics, 26(1), 149-168.

Bromwich, D.H., Cullather, R.I., & Van Woert, M.L. 1998. Antarctic precipitation and its contribution to the global sea-level budget. Annals of Glaciology, 27(220-227).

Chinn, T.J.H. 1987. Accelerated ablation at a glacier ice-cliff margin, Dry Valleys, Antarctica. Arctic and Alpine Research, 19(1), 71-80.

Chinn, T.J.H. 1998. Recent fluctuations of the Dry Valley glaciers, McMurdo Sound, Antarctica. Annals of Glaciology, 27, 119-124.

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Ferretti, D.F., Miller, J.B., White, J.W.C., Etheridge, D.M., Lassey, K.R., Lowe, D.C., MacFarling Meure, CM., Dreier, M.F., Trudinger, CM., van Ommen, T.D., & Langenfels, R.L. 2005. Unexpected changes to the global methane budget over the past 2000 years. Science, 309(5741), 1717-1720.

Hall, B.L., & Denton, G.H. 2000. Extent and chronology of the Ross Sea ice sheet and the Wilson Piedmont Glacier along the Scott Coast at and since the Last Glacial Maximum. Geografiska Annaler, 82A(2-3), 337-363.

Hamilton, G.S., & Whillans, I.M. 2000. Point measurements of mass balance of Greenland Ice Sheet using precision vertical Global Positioning System (GPS) surveys. Journal of Geophysical Research, 105(B7), 16,295-216,301.

Hamilton, G.S., Whillans, I.M., & Morgan, P.J. 1998. First point measurements of ice-sheet thickness change in Antarctica. Annals of Glaciology, 27,125-129.

Indermühle, A., Stocker, T.F., Joos, F., Fischer, H., Smith, H.J., Wahlen, M., Deck, B., Mastroianni, D., Tschumi, J., Blunier, T., Meyer, R., & Stauffer, B. 1999. Holocene carbon-cycle dynamics based on CO2 trapped in ice at Taylor Dome, Antarctica. Nature, 398,121-126.

IPCC 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Summary for Policymakers. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press. 21 pp.

Jones, P.D., New, M., Parker, D.E., Martin, S., & Rigor, I.G. 1999. Surface air temperatures and its changes over the past 150 years. Reviews of Geophysics, 37(2), 172-199.

King, J.C., & Turner, J. 1997. Antarctic Meteorology and Climatology. Cambridge: University Press Cambridge. 409 pp.

Legrand, M., & Mayewski, P.A. 1997. Glaciochemistry of polar ice cores: a review. Reviews of Geophysics, 35(3), 219-243.

Mann, M.E., & Jones, P.D. 2003. Global surface temperatures over the past two millennia. Geophysical Research Letters, 30(15).

Mayewski, P.A., Frezzotti, M., Bertler, N.A.N., van Ommen, T., Hamilton, G.S., Jacka, T.H., Welch, B., & Frey, M. 2005. The International Trans-Antarctic Scientifc Expedition (ITASE) - An Overview. Annals of Glaciology.

Mayewski, P.A., & White, F. 2002. The ice chronicles. Hanover, NH: University Press of New England. 233 pp.

Morse, D.L., Waddington, E.D., & Steig, E.J. 1998. Ice age storm trajectories inferred from radar stratigraphy at Taylor Dome, Antarctica. Geophysical Research Letters, 25(17), 3383-3386.

Mullan, B.A., Wratt, D.S., & Renwick, J.A. 2001. Transient model scenarios of climate change for New Zealand. Weather and Climate, 21, 3-34.

Patterson, N.G., Bertler, N.A.N., Naish, T.R., Morgenstern, U., & Rogers, K. 2005. ENSO variability in the deuterium excess record of a coastal Antarctic ice core from the McMurdo Dry Valleys, Victoria Land. Annals of Glaciology, 41, 140-146.

Ruddimann, W.F. 2003. The anthropogenic greenhouse era began thousands of years ago. Climatic Change, 61, 261-293.

Schrag, D.P. 2000. Of ice and elephants. Nature, 404, 23-24.

Sigman, D.M., & Boyle, E.A. 2000. Glacial / interglacial variations in atmospheric carbon dioxide. Nature, 407, 859-869.

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Steig, E.J., Hart, C.P., White, J.W.C., Cunningham, W.L., Davis, M.D., & Saltzman, E.S. 1998. Changes in climate, ocean and ice-sheet conditions in the Ross embayment, Antarctica, at 6ka. Annals of Glaciology, 27, 305-310.

Steig, E.J., Morse, D.L., Waddington, E.D., Stuiver, M., Grootes, P.M., Mayewski, P.A., Twickler, M.S., & Whitlow, S.I. 2000. Wisconsian and Holocene climate history from an ice core at Taylor Dome, Western Ross Embayment, Antarctica. Geografiska Annaler, 82A(2-3), 213-235.

Stocker, T.F. 1998. The seesaw effect. Science, 282, 61-62.

Stocker, T.F. 2002. North-South Connection. Science, 297,1814-1815f.

Vaughan, D.G., Corr, H.F.J., Doake, C.S.M., & Waddington, E.D. 1999. Distortion of isochronous layers in ice revealed by ground-penetrating radar. Nature, 398, 323-326.

White, J.W.C. 1993. Don't touch that dial. Nature, 364,186.

3. Acknowledgments

Include persons or organisations who have assisted or funded your science programme.

I would like to thank Antarctica New Zealand staff based in Christchurch and at Scott Base for their dedicated and innovative support with our project. I would like to thank Nathan Cross, Lyall Cross, and Paul Rogers for the assistance with my field work. I'm indebted for the support by Helicopter NZ staff, in particular Rob McPhail. I 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. I'm indebted to Dr. Tim Haskell, Industrial Research Limited for lending us their 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).