I am a civil engineer who studies how Antarctic sea ice affects and is affected by its environment. I also use remote sensing and geospatial tools to investigate both the icy world of Antarctica and and the civil engineering infrastructure of our urban communities. I first travelled to Aotearoa New Zealand in 1996 where I spent a few months interning at the International Antarctic Centre in Christchurch while studying towards a Masters degree at Clarkson University in Potsdam, New York. I also visited polar research centres in Japan and Germany during my postgraduate study, as well as interning for eight months at the NASA Goddard Space Flight Centre in Greenbelt, MD, USA. After completing my PhD in 2001, I returned to New Zealand and took up a post-doctoral fellowship in the Department of Physics at the University of Otago, where I participated in a Marsden funded research project that investigated the growth of Antarctic landfast sea ice. I made three separate trips to Antarctica during this time, including participating in a scientific cruise from Lyttelton Harbour to McMurdo Sound, Antarctic, and "wintering-over" at New Zealand's Scott Base from February – October 2003.
I next worked for 3+ years as an environmental engineer for the Duffill Watts Group, an engineering consultancy company based in Dunedin. While there I specialised in the design of water, wastewater and stormwater infrastructure, including taking on the role as the company's primary hydraulic modeller. Some of the larger projects that I was involved in include "Project Pure" in Wanaka (upgrade of Wanaka's wastewater system), the upgrade of Dunedin's Tahuna Wastewater Treatment Plant, and the strategic review of the Nelson Regional Sewerage Business Unit wastewater network.
I returned to the University of Otago in July 2008 as a faculty member in the School of Surveying. My primary roles in the School are delivering the civil engineering portion of the curriculum, establishing and maintaining links with the civil engineering industry and maintaining an active research profile in Antarctic sea ice and urban engineering infrastructure. I am fortunate to be involved in ongoing field studies in Antarctica, which has seen me routinely travel to Antarctica since 2010 with my colleagues from the Department of Physics, the University of Canterbury and NIWA. I have also have the great pleasure of working with a number of postgraduate students from both the School of Surveying and the Department of Physics.
Langhorne, P. J., Haas, C., Price, D., Rack, W., Leonard, G. H., Brett, G. M., & Urbini, S. (2023). Fast ice thickness distribution in the Western Ross Sea in late spring. Journal of Geophysical Research: Oceans. Advance online publication. doi: 10.1029/2022JC019459
Journal - Research Article
Richter, M. E., Smith, I. J., Everts, J. R., Russell, P., Langhorne, P. J., & Leonard, G. H. (2023). The effect of pseudofrazil particle entrainment on salinity measurements. Earth & Space Science, 10, e2022EA002564. doi: 10.1029/2022EA002564
Journal - Research Article
Fraser, A. D., Wongpan, P., Langhorne, P. J., Klekociuk, A. R., Kusahara, K., Lannuzel, D., … Leonard, G. H., Mahoney, A. R., … Wienecke, B. (2023). Antarctic landfast sea ice: A review of its physics, biogeochemistry and ecology. Reviews of Geophysics, 61, e2022RG000770. doi: 10.1029/2022RG000770
Journal - Research Article
Richter, M. E., Leonard, G. H., Smith, I. J., Langhorne, P. J., Mahoney, A. R., & Parry, M. (2022). Accuracy and precision when deriving sea-ice thickness from thermistor strings: A comparison of methods. Journal of Glaciology. Advance online publication. doi: 10.1017/jog.2022.108
Journal - Research Article
Leonard, G. H., Turner, K. E., Richter, M. E., Whittaker, M. S., & Smith, I. J. (2021). The anomalous winter 2019 sea-ice conditions in McMurdo Sound, Antarctica [Brief communication]. Cryosphere, 15(10), 4999-5006. doi: 10.5194/tc-15-4999-2021
Journal - Research Article
Haas, C., Langhorne, P. J., Rack, W., Leonard, G. H., Brett, G. M., Price, D., … Gough, A. J. (2021). Airborne mapping of the sub-ice platelet layer under fast ice in McMurdo Sound, Antarctica. Cryosphere, 15, 247-264. doi: 10.5194/tc-15-247-2021
Journal - Research Article
Rack, W., Price, D., Haas, C., Langhorne, P. J., & Leonard, G. H. (2021). Sea ice thickness in the Western Ross Sea. Geophysical Research Letters, 48, e2020GL090866. doi: 10.1029/2020GL090866
Journal - Research Article
Brett, G. M., Irvin, A., Rack, W., Haas, C., Langhorne, P. J., & Leonard, G. H. (2020). Variability in the distribution of fast ice and the sub-ice platelet layer near McMurdo ice shelf. Journal of Geophysical Research: Oceans, 125(3), e2019JC015678. doi: 10.1029/2019JC015678
Journal - Research Article
Frazer, E. K., Langhorne, P. J., Leonard, G. H., Robinson, N. J., & Schumayer, D. (2020). Observations of the size distribution of frazil ice in an Ice Shelf Water plume. Geophysical Research Letters, 47(e2020GL090498). doi: 10.1029/2020GL090498
Journal - Research Article
Kungl, A. F., Schumayer, D., Frazer, E. K., Langhorne, P. J., & Leonard, G. H. (2020). An oblate spheroidal model for multi-frequency acoustic back-scattering of frazil ice. Cold Regions Science & Technology, 177, 103122. doi: 10.1016/j.coldregions.2020.103122
Journal - Research Article
Moore, A., Daniel, B., Leonard, G., Regenbrecht, H., Rodda, J., Baker, L., Ryan, R., & Mills, S. (2020). Comparative usability of an augmented reality sandtable and 3D GIS for education. International Journal of Geographical Information Science, 34(2), 229-250. doi: 10.1080/13658816.2019.1656810
Journal - Research Article
Wongpan, P., Meiners, K. M., Langhorne, P. J., Heil, P., Smith, I. J., Leonard, G. H., … Haskell, T. G. (2018). Estimation of Antarctic land-fast sea ice algal biomass and snow thickness From under-ice radiance spectra in two contrasting areas. Journal of Geophysical Research: Oceans, 123(3), 1907-1923. doi: 10.1002/2017JC013711
Journal - Research Article
Nelson, M. J. S., Queste, B. Y., Smith, I. J., Leonard, G. H., Webber, B. G. M., & Hughes, K. G. (2017). Measurements of Ice Shelf Water beneath the front of the Ross Ice Shelf using gliders. Annals of Glaciology, 58(74), 41-50. doi: 10.1017/aog.2017.34
Journal - Research Article
Langhorne, P. J., Hughes, K. G., Gough, A. J., Smith, I. J., Williams, M. J. M., Robinson, N. J., … Leonard, G. H., … Haskell, T. G. (2015). Observed platelet ice distributions in Antarctic sea ice: An index for ocean-ice shelf heat flux. Geophysical Research Letters, 42(13), 5442-5451. doi: 10.1002/2015GL064508
Journal - Research Article
Mager, S. M., Leonard, G. H., Pauling, A. G., & Smith, I. J. (2015). A framework for estimating anchor ice extent at potential formation sites in McMurdo Sound, Antarctica. Annals of Glaciology, 56(69), 394-404. doi: 10.3189/2015AoG69A711
Journal - Research Article
Price, D., Beckers, J., Ricker, R., Kurtz, N., Rack, W., Haas, C., … Leonard, G., & Langhorne, P. J. (2015). Evaluation of CryoSat-2 derived sea-ice freeboard over fast ice in McMurdo Sound, Antarctica. Journal of Glaciology, 61(226), 285-300. doi: 10.3189/2015JoG14J157
Journal - Research Article
Smith, I. J., Gough, A. J., Langhorne, P. J., Mahoney, A. R., Leonard, G. H., Van Hale, R., Jendersie, S., & Haskell, T. G. (2015). First-year land-fast Antarctic sea ice as an archive of ice shelf meltwater fluxes. Cold Regions Science & Technology, 113, 63-70. doi: 10.1016/j.coldregions.2015.01.007
Journal - Research Article
Hughes, K. G., Langhorne, P. J., Leonard, G. H., & Stevens, C. L. (2014). Extension of an Ice Shelf Water plume model beneath sea ice with application in McMurdo Sound, Antarctica. Journal of Geophysical Research: Oceans, 119(12), 8662-8687. doi: 10.1002/2013JC009411
Journal - Research Article
Leonard, G. H., Mager, S. M., Pauling, A. G., Hughes, K. G., & Smith, I. J. (2014). Towards a process model for predicting potential anchor ice formation sites in coastal Antarctic waters. Journal of Spatial Science, 59(2), 297-312. doi: 10.1080/14498596.2014.913271
Journal - Research Article
Price, D., Rack, W., Langhorne, P. J., Haas, C., Leonard, G., & Barnsdale, K. (2014). The sub-ice platelet layer and its influence on freeboard to thickness conversion of Antarctic sea ice. Cryosphere, 8, 1031-1039. doi: 10.5194/tc-8-1031-2014
Journal - Research Article
Stevens, C. L., McPhee, M. G., Forrest, A. L., Leonard, G. H., Stanton, T., & Haskell, T. G. (2014). The influence of an Antarctic glacier tongue on near-field ocean circulation and mixing. Journal of Geophysical Research: Oceans, 119(4), 2344-2362. doi: 10.1002/2013JC009070
Journal - Research Article
Wright, J. W., Moore, A. B., & Leonard, G. H. (2014). Flow direction algorithms in a Hierarchical Hexagonal Surface Model. Journal of Spatial Science, 59(2), 333-346. doi: 10.1080/14498596.2014.918863
Journal - Research Article
Mager, S. M., Smith, I. J., Kempema, E., Thomson, B. J., & Leonard, G. H. (2013). Anchor ice in polar oceans. Progress in Physical Geography, 37(4), 468-483. doi: 10.1177/0309133313479815
Journal - Research Article
Leonard, G. H., Langhorne, P. J., Williams, M. J. M., Vennell, R., Purdie, C. R., Dempsey, D. E., … Frew, R. D. (2011). Evolution of supercooling under coastal Antarctic sea ice during winter. Antarctic Science, 23(4), 399-409. doi: 10.1017/s0954102011000265
Journal - Research Article
Wright, J. W., & Leonard, G. H. (2011). Evaluation of automated flow direction algorithms for defining urban stormwater catchment boundaries. New Zealand Surveyor, 301, 28-38.
Journal - Research Article
Leonard, G. H., Wright, J. W., & Haskell, T. G. (2011). Measurement of coastal sea ice vertical and horizontal displacements using a differential GPS and Total Station measurement array. Proceedings of the New Zealand Snow and Ice Research Group (SIRG) Annual Workshop. (pp. 23). Retrieved from http://www.sirg.org.nz/abstracts/SIRG2011FoxGlacier_Programme.pdf
Conference Contribution - Published proceedings: Abstract
Smith, I. J., Langhorne, P. J., Leonard, G. H., Gough, A. J., Frew, R. D., Trodahl, H. J., Mahoney, A. R., & Haskell, T. G. (2011). Sea ice thicknesses: Results from the 2010 Antarctic winter. Proceedings of the New Zealand Snow and Ice Research Group (SIRG) Annual Workshop. (pp. 21). Retrieved from http://www.sirg.org.nz/abstracts/SIRG2011FoxGlacier_Programme.pdf
Conference Contribution - Published proceedings: Abstract
Leonard, G. H., Purdie, C. R., Langhorne, P. J., Williams, M. J. M., & Haskell, T. G. (2010). Ice crystals in the water column: The view from an Acoustic Doppler Current Profiler (ADCP). Proceedings of the 20th IAHR International Symposium on Ice. [CD-ROM] Helsinki, Finland: International Association of Hydro-Environment Engineering and Research. [Full Paper]
Conference Contribution - Published proceedings: Full paper
Haskell, T., Mahoney, A., Gough, A., Leonard, G., Purdie, C., Williams, M., … Robinson, N., & Langhorne, P. (2010). Two winters on sea ice. Proceedings of the Annual Antarctic Conference: A Taste of the Ice. (pp. 42). Christchurch, New Zealand: Antarctica New Zealand. [Abstract]
Conference Contribution - Published proceedings: Abstract
Langhorne, P. J., Haskell, T. G., Gough, A. J., Leonard, G. H., Mahoney, A., Purdie, C. R., … Robinson, N. J. (2010). Antarctic landfast sea ice: The role of ice shelf-ocean interaction. Proceedings of the New Zealand Snow and Ice Research Group (SIRG) Annual Workshop. (pp. 23). Retrieved from http://www.sirg.org.nz/
Conference Contribution - Published proceedings: Abstract
Leonard, G., Stevens, C., Williams, M., Mahoney, A., Robinson, N., Langhorne, P., & Haskell, T. (2010). ADCP detection of ice crystals in the water column. Proceedings of the Annual Antarctic Conference: A Taste of the Ice. (pp. 67). Christchurch, New Zealand: Antarctica New Zealand. [Abstract]
Conference Contribution - Published proceedings: Abstract
Smith, I. J., Langhorne, P. J., Leonard, G. H., Gough, A. J., Frew, R. D., Mahoney, A. R., & Haskell, T. G. (2010). Sea ice thickness: Measurement techniques used in the field. Proceedings of the New Zealand Snow and Ice Research Group (SIRG) Annual Workshop. (pp. 36). Retrieved from http://www.sirg.org.nz/
Conference Contribution - Published proceedings: Abstract
Purdie, C., Langhorne, P. J., Leonard, G. H., & Haskell, T. G. (2007). Desalination of first-year landfast sea ice in McMurdo Sound, Antarctica. Proceedings of the Polar Dynamics Conference. Retrieved from http://web.gfi.uib.no/conference2007/abstracts/S2posters.html#CPurdie
Conference Contribution - Published proceedings: Abstract
Albrecht, N., Vennell, R., Williams, M., Stevens, C., Langhorne, P., Leonard, G., & Haskell, T. (2006). Observation of sub-inertial internal tides in McMurdo Sound, Antarctica. Geophysical Research Letters, 33, L24606. doi: 10.1029/2006GL027377
Journal - Research Article
Leonard, G. H., Purdie, C. R., Langhorne, P. J., Haskell, T. G., Williams, M. J. M., & Frew, R. D. (2006). Observations of platelet ice growth and oceanographic conditions during the winter of 2003 in McMurdo Sound, Antarctica. Journal of Geophysical Research, 111, C04012. doi: 10.1029/2005JC002952
Journal - Research Article
Purdie, C. R., Langhorne, P. J., Leonard, G. H., & Haskell, T. G. (2006). Growth of first-year landfast Antarctic sea ice determined from winter temperature measurements. Annals of Glaciology, 44, 170-176.
Journal - Research Article
Langhorne, P. J., Purdie, C. R., Smith, I. J., Leonard, G., Kempema, E. W., Petrich, C., Gribble, M. A., Bond, P. E., & Haskell, T. G. (2006). Antarctic landfast sea ice: The role of platelet ice. Proceedings of the 18th International Association of Hydraulic Engineering and Research International Symposium on Ice. (pp. 285-292). IAHR. Retrieved from http://web2.clarkson.edu/projects/iahrice/IAHR%202006/program.html
Conference Contribution - Published proceedings: Full paper
Gamble, R., Wilson, G. S., Langhorne, P. J., Enlow, R., & Leonard, G. (2006). Independent flow regimes in the Southern McMurdo and Ross Ice Shelves: New evidence from velocity analysis of Landsat images and numerical modelling. Proceedings of the XVIII Scientific Committee on Antarctic Research Open Science Conference. Retrieved from http://www.uam.es/otros/cn-scar/zz/scar_sessions_type.html
Conference Contribution - Published proceedings: Abstract