About
Professor Adrian Luckman is a member of the Geography Department at Swansea University.
D.Phil., Electronic Engineering, University of York, 1991; BSc. (Hons) Electronic Engineering, University of York, 1987
Professor Adrian Luckman
Chair
Geography
Telephone number
+44 (0) 1792 295524
Office - 231
Second Floor
Wallace Building
Singleton Campus
Second Floor
Wallace Building
Singleton Campus
Available For Postgraduate Supervision
Areas Of Expertise
- Satellite Earth Observation
- Geographic Information Systems (GIS)
- Glaciology
- Iceberg calving
- Glacier dynamics
- Glacier surges
- Ice shelf stability
Career Highlights
Teaching Interests
Research
Geographic Information Systems (GIS)
Earth Observation
Glaciology
The Cryosphere
Ice in nature is beautiful, abundant, intriguing, ever changing, and fragile. It flows, fractures and behaves in a way which reflects both its crystalline structure, and its great volume. I satisfy my fascination for glaciers and ice sheets by monitoring them from space, using satellite imaging systems to study how they behave and how they are responding to climate change.
I specialize in the use of synthetic aperture radar (SAR) which uses microwave energy to acquire images regardless of cloud cover and polar night – a capability that is particularly valuable in the Arctic and Antarctic. My expertise is in using regularly acquired images to derive surface flow rates and dynamic change.
My work has encompassed the Himalayas, Greenland, Svalbard and Antarctica, and I have been lucky enough to do fieldwork in all these regions.
My recent work has concentrated on the stability of ice shelves – the floating extensions of glaciers that fringe most of Antarctica, and iceberg calving – the process by which ice is lost to the ocean. Calving events range from small chunks falling from glaciers to huge episodes, such as the formation in 2017 of Iceberg A-68, one quarter the size of Wales.
For some examples of my work, please see my Wordpress page:
Publications
Research Highlights
-
Bassis, J., Crawford, A., Kachuck, S., Benn, D., Walker, C., Millstein, J., Duddu, R., Åström, J., Fricker, H., & Luckman, A. (2024). Stability of Ice Shelves and Ice Cliffs in a Changing Climate. Annual Review of Earth and Planetary Sciences, 52(1)
-
Lempidakis, M., Wilson, R., Luckman, A., & Metcalfe, R. (2018). What can knowledge of the energy landscape tell us about animal movement trajectories and space use? A case study with humans. Journal of Theoretical Biology, 457, 101-111.
-
Shakesby, R., Hiemstra, J., Kulessa, B., & Luckman, A. (2018). Re-assessment of the age and depositional origin of the Paviland Moraine, Gower, south Wales, UK. Boreas, 47(2), 577-592.
-
Fehlmann, G., O’Riain, M., Kerr-Smith, C., Hailes, S., Luckman, A., Shepard, E., & King, A. (2017). Extreme behavioural shifts by baboons exploiting risky, resource-rich, human-modified environments. Scientific Reports, 7(1)
-
Bevan, S., Luckman, A., Hubbard, B., Kulessa, B., Ashmore, D., Munneke, P., O'Leary, M., Booth, A., Sevestre, H., & McGrath, D. (2017). Centuries of intense surface melt on Larsen C Ice Shelf. The Cryosphere, 11(6), 2743-2753.
-
Brisbourne, A., Kulessa, B., Hudson, T., Harrison, L., Luckman, A., Pearce, E., Hubbard, B., Ashmore, D., Bevan, S., Holland, P., Nichols, K., White, J., Smith, A., & Booth, A. (2019). An updated seabed bathymetry beneath Larsen C Ice Shelf, west Antarctic. Earth System Science Data Discussions
-
Kulessa, B., Booth, A., O'Leary, M., McGrath, D., King, E., Luckman, A., Holland, P., Jansen, D., Bevan, S., Thompson, S., & Hubbard, B. (2019). Seawater softening of suture zones inhibits fracture propagation in Antarctic ice shelves. Nature Communications, 10(1)
-
Brisbourne, A., Kulessa, B., Hudson, T., Harrison, L., Holland, P., Luckman, A., Bevan, S., Ashmore, D., Hubbard, B., Pearce, E., White, J., Booth, A., Nicholls, K., & Smith, A. (2020). An updated seabed bathymetry beneath Larsen C Ice Shelf, Antarctic Peninsula. Earth System Science Data, 12(2), 887-896.
-
Bevan, S., Luckman, A., Hendon, H., & Wang, G. (2020). The 2020 Larsen C Ice Shelf surface melt is a 40-year record high. The Cryosphere, 14(10), 3551-3564.
-
Bevan, S., Luckman, A., Benn, D., Adusumilli, S., & Crawford, A. (2021). Brief communication: Thwaites Glacier cavity evolution. The Cryosphere, 15(7), 3317-3328.
All Research
Journal Articles
-
Crawford, A., Åström, J., Benn, D., Luckman, A., Gladstone, R., Zwinger, T., Robertsén, F., & Bevan, S. (2024). Calving Dynamics and the Potential Impact of Mélange Buttressing at the Western Calving Front of Thwaites Glacier, West Antarctica. Journal of Geophysical Research: Earth Surface, 129(10)
-
Bassis, J., Crawford, A., Kachuck, S., Benn, D., Walker, C., Millstein, J., Duddu, R., Åström, J., Fricker, H., & Luckman, A. (2024). Stability of Ice Shelves and Ice Cliffs in a Changing Climate. Annual Review of Earth and Planetary Sciences, 52(1)
-
Watkins, R., Bassis, J., Thouless, M., & Luckman, A. (2024). High Basal Melt Rates and High Strain Rates Lead to More Fractured Ice. Journal of Geophysical Research: Earth Surface, 129(4)
-
Marsh, O., Luckman, A., & Hodgson, D. (2024). Brief communication: Rapid acceleration of the Brunt Ice Shelf after calving of iceberg A-81. The Cryosphere, 18(2), 705-710.
-
Benn, D., Todd, J., Luckman, A., Bevan, S., Chudley, T., Åström, J., Zwinger, T., Cook, S., & Christoffersen, P. (2023). Controls on calving at a large Greenland tidewater glacier: stress regime, self-organised criticality and the crevasse-depth calving law. Journal of Glaciology, 0, 1-16.
-
Holland, P., Bevan, S., & Luckman, A. (2023). Strong Ocean Melting Feedback During the Recent Retreat of Thwaites Glacier. Geophysical Research Letters, 50(8)
-
Thompson, S., Kulessa, B., Luckman, A., Halpin, J., Greenbaum, J., Pelle, T., Habbal, F., Guo, J., Jong, L., Roberts, J., Sun, B., & Blankenship, D. (2023). Glaciological history and structural evolution of the Shackleton Ice Shelf system, East Antarctica, over the past 60 years. The Cryosphere, 17(1), 157-174.
-
Benn, D., Hewitt, I., & Luckman, A. (2022). Enthalpy balance theory unifies diverse glacier surge behaviour. Annals of Glaciology, 63(87-89), 88-94.
-
Goliber, S., Black, T., Catania, G., Lea, J., Olsen, H., Cheng, D., Bevan, S., Bjørk, A., Bunce, C., Brough, S., Carr, J., Cowton, T., Gardner, A., Fahrner, D., Hill, E., Joughin, I., Korsgaard, N., Luckman, A., Moon, T...., & Zhang, E. (2022). TermPicks: a century of Greenland glacier terminus data for use in scientific and machine learning applications. The Cryosphere, 16(8), 3215-3233.
-
Benn, D., Luckman, A., Åström, J., Crawford, A., Cornford, S., Bevan, S., Zwinger, T., Gladstone, R., Alley, K., Pettit, E., & Bassis, J. (2022). Rapid fragmentation of Thwaites Eastern Ice Shelf. The Cryosphere, 16(6), 2545-2564.
-
Oerlemans, J., Kohler, J., & Luckman, A. (2022). Modelling the mass budget and future evolution of Tunabreen, central Spitsbergen. The Cryosphere, 16(5), 2115-2126.
-
Alley, K., Wild, C., Luckman, A., Scambos, T., Truffer, M., Pettit, E., Muto, A., Wallin, B., Klinger, M., Sutterley, T., Child, S., Hulen, C., Lenaerts, J., Maclennan, M., Keenan, E., & Dunmire, D. (2021). Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf. The Cryosphere, 15(11), 5187-5203.
-
Bevan, S., Luckman, A., Benn, D., Adusumilli, S., & Crawford, A. (2021). Brief communication: Thwaites Glacier cavity evolution. The Cryosphere, 15(7), 3317-3328.
-
Bevan, S., Luckman, A., Hendon, H., & Wang, G. (2020). The 2020 Larsen C Ice Shelf surface melt is a 40-year record high. The Cryosphere, 14(10), 3551-3564.
-
Brisbourne, A., Kulessa, B., Hudson, T., Harrison, L., Holland, P., Luckman, A., Bevan, S., Ashmore, D., Hubbard, B., Pearce, E., White, J., Booth, A., Nicholls, K., & Smith, A. (2020). An updated seabed bathymetry beneath Larsen C Ice Shelf, Antarctic Peninsula. Earth System Science Data, 12(2), 887-896.
-
Bevan, S., Luckman, A., Benn, D., Cowton, T., & Todd, J. (2019). Impact of warming shelf waters on ice mélange and terminus retreat at a large SE Greenland glacier. The Cryosphere, 13(9), 2303-2315.
-
Howe, J., Husum, K., Inall, M., Coogan, J., Luckman, A., Arosio, R., Abernethy, C., & Verchili, D. (2019). Autonomous underwater vehicle (AUV) observations of recent tidewater glacier retreat, western Svalbard. Marine Geology, 417, 106009
-
How, P., Schild, K., Benn, D., Noormets, R., Kirchner, N., Luckman, A., Vallot, D., Hulton, N., & Borstad, C. (2019). Calving controlled by melt-under-cutting: detailed calving styles revealed through time-lapse observations. Annals of Glaciology, 1-12.
-
Kulessa, B., Booth, A., O'Leary, M., McGrath, D., King, E., Luckman, A., Holland, P., Jansen, D., Bevan, S., Thompson, S., & Hubbard, B. (2019). Seawater softening of suture zones inhibits fracture propagation in Antarctic ice shelves. Nature Communications, 10(1)
-
Brisbourne, A., Kulessa, B., Hudson, T., Harrison, L., Luckman, A., Pearce, E., Hubbard, B., Ashmore, D., Bevan, S., Holland, P., Nichols, K., White, J., Smith, A., & Booth, A. (2019). An updated seabed bathymetry beneath Larsen C Ice Shelf, west Antarctic. Earth System Science Data Discussions
-
Benn, D., Jones, R., Luckman, A., Fürst, J., Hewitt, I., & Sommer, C. (2019). Mass and enthalpy budget evolution during the surge of a polythermal glacier: a test of theory. Journal of Glaciology, 65(253), 717-731.
-
Sergeant, A., Mangeney, A., Yastrebov, V., Walter, F., Montagner, J., Castelnau, O., Stutzmann, E., Bonnet, P., Ralaiarisoa, V., Bevan, S., & Luckman, A. (2019). Monitoring Greenland ice sheet buoyancy-driven calving discharge using glacial earthquakes. Annals of Glaciology, 60(79), 75-95.
-
Nuth, C., Gilbert, A., Köhler, A., McNabb, R., Schellenberger, T., Sevestre, H., Weidle, C., Girod, L., Luckman, A., & Kääb, A. (2019). Dynamic vulnerability revealed in the collapse of an Arctic tidewater glacier. Scientific Reports, 9(1)
-
Young, T., Christoffersen, P., Doyle, S., Nicholls, K., Stewart, C., Hubbard, B., Hubbard, A., Lok, L., Brennan, P., Benn, D., Luckman, A., Bougamont, M., & Luckman, A. (2019). Physical Conditions of Fast Glacier Flow: 3. Seasonally-Evolving Ice Deformation on Store Glacier, West Greenland. Journal of Geophysical Research: Earth Surface, 124(1), 245-267.
-
Bevan, S., Luckman, A., Munneke, P., Hubbard, B., Kulessa, B., & Ashmore, D. (2018). Decline in Surface Melt Duration on Larsen C Ice Shelf Revealed by The Advanced Scatterometer (ASCAT). Earth and Space Science, 5(10), 578-591.
-
Lovell, H., Benn, D., Lukas, S., Ottesen, D., Luckman, A., Hardiman, M., Barr, I., Boston, C., & Sevestre, H. (2018). Multiple Late Holocene surges of a High-Arctic tidewater glacier system in Svalbard. Quaternary Science Reviews, 201, 162-185.
-
Lempidakis, M., Wilson, R., Luckman, A., & Metcalfe, R. (2018). What can knowledge of the energy landscape tell us about animal movement trajectories and space use? A case study with humans. Journal of Theoretical Biology, 457, 101-111.
-
Schild, K., Renshaw, C., Benn, D., Luckman, A., Hawley, R., How, P., Trusel, L., Cottier, F., Pramanik, A., Hulton, N., & Luckman, A. (2018). Glacier Calving Rates Due to Subglacial Discharge, Fjord Circulation, and Free Convection. Journal of Geophysical Research: Earth Surface, 123(9), 2189-2204.
-
Munneke, P., Luckman, A., Bevan, S., Smeets, C., Gilbert, E., Broeke, M., Wang, W., Zender, C., Hubbard, B., Ashmore, D., Orr, A., King, J., & Kulessa, B. (2018). Intense Winter Surface Melt on an Antarctic Ice Shelf. Geophysical Research Letters, 45(15), 7615-7623.
-
Boncori, J., Andersen, M., Dall, J., Kusk, A., Kamstra, M., Andersen, S., Bechor, N., Bevan, S., Bignami, C., Gourmelen, N., Joughin, I., Jung, H., Luckman, A., Mouginot, J., Neelmeijer, J., Rignot, E., Scharrer, K., Nagler, T., Scheuchl, B., & Strozzi, T. (2018). Intercomparison and Validation of SAR-Based Ice Velocity Measurement Techniques within the Greenland Ice Sheet CCI Project. Remote Sensing, 10(6), 929
-
Sevestre, H., Benn, D., Luckman, A., Nuth, C., Kohler, J., Lindbäck, K., & Pettersson, R. (2018). Tidewater Glacier Surges Initiated at the Terminus. Journal of Geophysical Research: Earth Surface, 123(5), 1035-1051.
-
Shakesby, R., Hiemstra, J., Kulessa, B., & Luckman, A. (2018). Re-assessment of the age and depositional origin of the Paviland Moraine, Gower, south Wales, UK. Boreas, 47(2), 577-592.
-
Todd, J., Christoffersen, P., Zwinger, T., Råback, P., Chauché, N., Benn, D., Luckman, A., Ryan, J., Toberg, N., Slater, D., & Hubbard, A. (2018). A Full-Stokes 3-D Calving Model Applied to a Large Greenlandic Glacier. Journal of Geophysical Research: Earth Surface
-
Vallot, D., Åström, J., Zwinger, T., Pettersson, R., Everett, A., Benn, D., Luckman, A., Pelt, W., Nick, F., & Kohler, J. (2018). Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard. The Cryosphere, 12(2), 609-625.
-
VALLOT, D., PETTERSSON, R., Luckman, A., BENN, D., ZWINGER, T., VAN PELT, W., KOHLER, J., SCHÄFER, M., CLAREMAR, B., & HULTON, N. (2017). Basal dynamics of Kronebreen, a fast-flowing tidewater glacier in Svalbard: non-local spatio-temporal response to water input. Journal of Glaciology, 63(242), 1012-1024.
-
King, J., Kirchgaessner, A., Bevan, S., Elvidge, A., Kuipers Munneke, P., Luckman, A., Orr, A., Renfrew, I., van den Broeke, M., Luckman, A., & Bevan, S. (2017). The Impact of Föhn Winds on Surface Energy Balance During the 2010-2011 Melt Season Over Larsen C Ice Shelf, Antarctica. Journal of Geophysical Research: Atmospheres, 122(22), 12,062-12,076.
-
Benn, D., Thompson, S., Gulley, J., Mertes, J., Luckman, A., & Nicholson, L. (2017). Structure and evolution of the drainage system of a Himalayan debris-covered glacier, and its relationship with patterns of mass loss. The Cryosphere, 11(5), 2247-2264.
-
Bevan, S., Luckman, A., Hubbard, B., Kulessa, B., Ashmore, D., Munneke, P., O'Leary, M., Booth, A., Sevestre, H., & McGrath, D. (2017). Centuries of intense surface melt on Larsen C Ice Shelf. The Cryosphere, 11(6), 2743-2753.
-
Benn, D., Cowton, T., Todd, J., & Luckman, A. (2017). Glacier Calving in Greenland. Current Climate Change Reports, 3(4), 282-290.
-
How, P., Benn, D., Hulton, N., Hubbard, B., Luckman, A., Sevestre, H., van Pelt, W., Lindbäck, K., Kohler, J., & Boot, W. (2017). Rapidly changing subglacial hydrological pathways at a tidewater glacier revealed through simultaneous observations of water pressure, supraglacial lakes, meltwater plumes and surface velocities. The Cryosphere, 11(6), 2691-2710.
-
How, P., Benn, D., Hulton, N., Hubbard, B., Luckman, A., Sevestre, H., Pelt, W., Lindbäck, K., Kohler, J., & Boot, W. (2017). Rapidly changing subglacial hydrological pathways at a tidewater glacier revealed through simultaneous observations of water pressure, supraglacial lakes, meltwater plumes and surface velocities. The Cryosphere, 11(6), 2691-2710.
-
Fehlmann, G., O’Riain, M., Kerr-Smith, C., Hailes, S., Luckman, A., Shepard, E., & King, A. (2017). Extreme behavioural shifts by baboons exploiting risky, resource-rich, human-modified environments. Scientific Reports, 7(1)
-
Munneke, P., McGrath, D., Medley, B., Luckman, A., Bevan, S., Kulessa, B., Jansen, D., Booth, A., Smeets, P., Hubbard, B., Ashmore, D., Broeke, M., Sevestre, H., Steffen, K., Shepherd, A., & Gourmelen, N. (2017). Observationally constrained surface mass balance of Larsen C ice shelf, Antarctica. The Cryosphere, 11(6), 2411-2426.
-
Benn, D., Thompson, S., Gulley, J., Mertes, J., Luckman, A., & Nicholson, L. (2017). Structure and evolution of the drainage system of a Himalayan debris-covered glacier, and its relationship with patterns of mass loss. The Cryosphere, 11(5), 2247-2264.
-
Benn, D., Thompson, S., Gulley, J., Mertes, J., Luckman, A., & Nicholson, L. (2017). Structure and evolution of the drainage system of a Himalayan debris-covered glacier, and its relationship with patterns of mass loss. The Cryosphere, 11(5), 2247-2264.
-
BENN, D., ÅSTRÖM, J., ZWINGER, T., TODD, J., NICK, F., COOK, S., HULTON, N., & Luckman, A. (2017). Melt-under-cutting and buoyancy-driven calving from tidewater glaciers: new insights from discrete element and continuum model simulations. Journal of Glaciology, 63(240), 691-702.
-
Ashmore, D., Hubbard, B., Luckman, A., Kulessa, B., Bevan, S., Booth, A., Kuipers Munneke, P., O'Leary, M., Sevestre, H., & Holland, P. (2017). Ice and firn heterogeneity within Larsen C Ice Shelf from borehole optical televiewing. Journal of Geophysical Research: Earth Surface
-
Everett, A., Murray, T., Selmes, N., Rutt, I., Luckman, A., James, J., Clason, C., O'Leary, M., Karunarathna, H., Moloney, V., & Reeve, D. (2016). Annual down-glacier drainage of lakes and water-filled crevasses at Helheim Glacier, southeast Greenland. Journal of Geophysical Research: Earth Surface, 121(10), 1819-1833.
-
Hubbard, B., Luckman, A., Bevan, S., Ashmore, D., Kulessa, B., Munneke, P., Philippe, M., Jansen, D., Booth, A., Sevestre, H., Tison, J., O’Leary, M., & Rutt, I. (2016). Massive subsurface ice formed by refreezing of ice-shelf melt ponds. Nature Communications, 7(1), 11897
-
Cook, A., Holland, P., Meredith, M., Murray, T., Luckman, A., & Vaughan, D. (2016). Ocean forcing of glacier retreat in the western Antarctic Peninsula. Science, 353(6296), 283-286.
-
THOMPSON, S., BENN, D., MERTES, J., & Luckman, A. (2016). Stagnation and mass loss on a Himalayan debris-covered glacier: processes, patterns and rates. Journal of Glaciology, 62(233), 467-485.
-
Paul, F., Bolch, T., Kääb, A., Nagler, T., Nuth, C., Scharrer, K., Shepherd, A., Strozzi, T., Ticconi, F., Bhambri, R., Berthier, E., Bevan, S., Gourmelen, N., Heid, T., Jeong, S., Kunz, M., Lauknes, T., Luckman, A., Merryman Boncori, J...., & Van Niel, T. (2015). The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products. Remote Sensing of Environment, 162, 408-426.
-
Quincey, D., Glasser, N., Cook, S., & Luckman, A. (2015). Heterogeneity in Karakoram glacier surges. Journal of Geophysical Research: Earth Surface, 120(7), 1288-1300.
-
Flink, A., Noormets, R., Kirchner, N., Benn, D., Luckman, A., & Lovell, H. (2015). The evolution of a submarine landform record following recent and multiple surges of Tunabreen glacier, Svalbard. Quaternary Science Reviews, 108, 37-50.
-
Jansen, D., Luckman, A., Cook, A., Bevan, S., Kulessa, B., Hubbard, B., Holland, P., Luckman, A., Kulessa, B., & Bevan, S. (2015). Brief Communication: Newly developing rift in Larsen C Ice Shelf presents significant risk to stability. The Cryosphere, 9(3), 1223-1227.
-
Paul, F., Bolch, T., Kääb, A., Nagler, T., Nuth, C., Scharrer, K., Shepherd, A., Strozzi, T., Ticconi, F., Bhambri, R., Berthier, E., Bevan, S., Gourmelen, N., Heid, T., Jeong, S., Kunz, M., Lauknes, T., Luckman, A., Merryman Boncori, J...., & Van Niel, T. (2015). The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products. Remote Sensing of Environment, 162, 408-426.
-
Luckman, A., Benn, D., Cottier, F., Bevan, S., Nilsen, F., & Inall, M. (2015). Calving rates at tidewater glaciers vary strongly with ocean temperature. Nature Communications, 6(1), 8566
-
Murray, T., Scharrer, K., Selmes, N., Booth, A., James, T., Bevan, S., Bradley, J., Cook, S., Llana, L., Drocourt, Y., Dyke, L., Goldsack, A., Hughes, A., Luckman, A., McGovern, J., Luckman, A., Murray, T., & Bevan, S. (2015). Extensive Retreat of Greenland Tidewater Glaciers, 2000–2010. Arctic, Antarctic, and Alpine Research, 47(3), 427-447.
-
Wilson, G., Holton, M., Walker, J., Jones, M., Grundy, E., Davies, I., Clarke, D., Luckman, A., Russill, N., Wilson, V., Plummer, R., & Wilson, R. (2015). A new perspective on how humans assess their surroundings; derivation of head orientation and its role in ‘framing’ the environment. PeerJ, 3(e908), e908-29.
-
Bevan, S., Luckman, A., Khan, S., & Murray, T. (2015). Seasonal dynamic thinning at Helheim Glacier. Earth and Planetary Science Letters, 415, 47-53.
-
Cook, A., Vaughan, D., Luckman, A., Murray, T., Luckman, A., & Murray, T. (2014). A new Antarctic Peninsula glacier basin inventory and observed area changes since the 1940s. Antarctic Science, 26(06), 614-624.
-
Luckman, A., Elvidge, A., Jansen, D., Kulessa, B., Kuipers Munneke, P., King, J., & Barrand, N. (2014). Surface melt and ponding on Larsen C Ice Shelf and the impact of föhn winds. Antarctic Science, 26(6), 625-635.
-
Holt, T., Glasser, N., Fricker, H., Padman, L., Luckman, A., King, O., Quincey, D., Siegfried, M., & Luckman, A. (2014). The structural and dynamic responses of Stange Ice Shelf to recent environmental change. Antarctic Science, 26(6), 646-660.
-
Khan, S., Kjeldsen, K., Kjær, K., Bevan, S., Luckman, A., Aschwanden, A., Bjørk, A., Korsgaard, N., Box, J., van den Broeke, M., van Dam, T., Fitzner, A., Luckman, A., & Bevan, S. (2014). Glacier dynamics at Helheim and Kangerdlugssuaq glaciers, southeast Greenland, since the Little Ice Age. The Cryosphere, 8(4), 1497-1507.
-
Cook, S., Rutt, I., Murray, T., Luckman, A., Zwinger, T., Selmes, N., Goldsack, A., James, T., Luckman, A., Murray, T., Rutt, I., & Selmes, N. (2014). Modelling environmental influences on calving at Helheim Glacier in eastern Greenland. The Cryosphere, 8(3), 827-841.
-
Kulessa, B., Jansen, D., Luckman, A., King, E., & Sammonds, P. (2014). Marine ice regulates the future stability of a large Antarctic ice shelf. Nature Communications, 5(1)
-
Cook, S., Rutt, I., Murray, T., Luckman, A., Zwinger, T., Selmes, N., Goldsack, A., & James, T. (2014). Modelling environmental influences on calving at Helheim Glacier in eastern Greenland. The Cryosphere, 8(3), 827-841.
-
Quincey, D. & Luckman, A. (2014). Brief Communication: On the magnitude and frequency of Khurdopin glacier surge events. The Cryosphere, 8(2), 571-574.
-
Jansen, D., Luckman, A., Kulessa, B., Holland, P., & King, E. (2013). Marine ice formation in a suture zone on the Larsen C Ice Shelf and its influence on ice shelf dynamics. Journal of Geophysical Research: Earth Surface, 118(3), 1628-1640.
-
Schofield, G., Dimadi, A., Fossette, S., Katselidis, K., Koutsoubas, D., Lilley, M., Luckman, A., Pantis, J., Karagouni, A., Hays, G., & Keller, R. (2013). Satellite tracking large numbers of individuals to infer population level dispersal and core areas for the protection of an endangered species. Diversity and Distributions, 19(7), 834-844.
-
Mansell, D., Luckman, A., & Murray, T. (2012). Dynamics of tidewater surge-type glaciers in northwest Svalbard. Journal of Glaciology, 58(207), 110
-
Bevan, S., Murray, T., Luckman, A., Hanna, E., & Huybrechts, P. (2012). Stable dynamics in a Greenland tidewater glacier over 26 years despite reported thinning. Annals of Glaciology, 53(60), 241-248.
-
Shepherd, A., Ivins, E., G, A., Barletta, V., Bentley, M., Bettadpur, S., Briggs, K., Bromwich, D., Forsberg, R., Galin, N., Horwath, M., Jacobs, S., Joughin, I., King, M., Lenaerts, J., Li, J., Ligtenberg, S., Luckman, A., Luthcke, S...., & Luckman, A. (2012). A Reconciled Estimate of Ice-Sheet Mass Balance. Science, 338(6111), 1183-1189.
-
Benn, D., Bolch, T., Hands, K., Gulley, J., Luckman, A., Nicholson, L., Quincey, D., Thompson, S., Toumi, R., Wiseman, S., & Luckman, A. (2012). Response of debris-covered glaciers in the Mount Everest region to recent warming, and implications for outburst flood hazards. Earth-Science Reviews, 114(1-2), 156-174.
-
Thompson, S., Benn, D., Dennis, K., & Luckman, A. (2012). A rapidly growing moraine-dammed glacial lake on Ngozumpa Glacier, Nepal. Geomorphology, 145-146, 1
-
Bevan, S., Luckman, A., Murray, T., Luckman, A., & Bevan, S. (2012). Glacier dynamics over the last quarter of a century at Helheim, Kangerdlugssuaq and 14 other major Greenland outlet glaciers. The Cryosphere, 6(5), 923-937.
-
Thompson, S., Kulessa, B., & Luckman, A. (2012). Integrated electrical resistivity tomography (ERT) and self-potential (SP) techniques for assessing hydrological processes within glacial lake moraine dams. Journal of Glaciology, 58(211), 849-858.
-
NICK, F., LUCKMAN, A., VIELI, A., VEEN, C., D. VAN, A., WAL, R., PATTYN, F., HUBBARD, A., FLORICIOIU, D., & Luckman, A. (2012). The response of Petermann Glacier, Greenland, to large calving events, and its future stability in the context of atmospheric and oceanic warming. Journal of Glaciology, 58(208), 229-239.
-
Luckman, A., Jansen, D., Kulessa, B., King, E., Sammonds, P., Benn, D., & Luckman, A. (2012). Basal crevasses in Larsen C Ice Shelf and implications for their global abundance. The Cryosphere, 6(1), 113-123.
-
Cook, A., Murray, T., Luckman, A., Vaughan, D., Barrand, N., & Luckman, A. (2012). A new 100-m Digital Elevation Model of the Antarctic Peninsula derived from ASTER Global DEM: methods and accuracy assessment. Earth System Science Data, 4(1), 129-142.
-
Quincey, D., Braun, M., Glasser, N., Bishop, M., Hewitt, K., Luckman, A., & Luckman, A. (2011). Karakoram glacier surge dynamics. Geophysical Research Letters, 38(18), n/a
-
Christoffersen, P., Mugford, R., Heywood, K., Joughin, I., Dowdeswell, J., Syvitski, J., Luckman, A., Benham, T., & Luckman, A. (2011). Warming of waters in an East Greenland fjord prior to glacier retreat: mechanisms and connection to large-scale atmospheric conditions. The Cryosphere, 5(3), 701
-
Murray, T., Scharrer, K., James, T., Dye, S., Hanna, E., Booth, A., Selmes, N., Luckman, A., Hughes, A., Cook, S., Huybrechts, P., Luckman, A., Murray, T., James, T., & Selmes, N. (2010). Ocean regulation hypothesis for glacier dynamics in southeast Greenland and implications for ice sheet mass changes. Journal of Geophysical Research, 115(F3)
-
Luckman, A., Padman, L., & Jansen, D. (2010). Persistent iceberg groundings in the western Weddell Sea, Antarctica. Remote Sensing of Environment, 114(2), 385
-
Jansen, D., Kulessa, B., Sammonds, P., Luckman, A., King, E., Glasser, N., Luckman, A., & Kulessa, B. (2010). Present stability of the Larsen C ice shelf, Antarctic Peninsula. Journal of Glaciology, 56(198), 593
-
Sykes, H., Murray, T., & Luckman, A. (2009). The location of the grounding zone of Evans Ice Stream, Antarctica, investigated using SAR interferometry and modelling. Annals of Glaciology, 50(52), 35
-
Quincey, D., Luckman, A., & Luckman, A. (2009). Progress in satellite remote sensing of ice sheets. Progress in Physical Geography, 33(4), 547
-
Hanna, E., Cappelen, J., Fettweis, X., Huybrechts, P., Luckman, A., Ribergaard, M., & Luckman, A. (2009). Hydrologic response of the Greenland ice sheet: the role of oceanographic warming. Hydrological Processes, 23(1), 7-30.
-
Gulley, J., Benn, D., Müller, D., Luckman, A., & Luckman, A. (2009). A cut-and-closure origin for englacial conduits in uncrevassed regions of polythermal glaciers. Journal of Glaciology, 55(189), 66
-
Glasser, N., Kulessa, B., Luckman, A., Jansen, D., King, E., Sammonds, P., Scambos, T., Jezek, K., Luckman, A., & Kulessa, B. (2009). Surface structure and stability of the Larsen C ice shelf, Antarctic Peninsula. Journal of Glaciology, 55(191), 400
-
Benn, D., Gulley, J., Luckman, A., Adamek, A., & Glowacki, P. (2009). Englacial drainage systems formed by hydrologically driven crevasse propagation. Journal of Glaciology, 55(191), 513-523.
-
Quincey, D., Luckman, A., Benn, D., & Luckman, A. (2009). Quantification of Everest region glacier velocities between 1992 and 2002, using satellite radar interferometry and feature tracking. Journal of Glaciology, 55(192), 596-606.
-
Quincey, D., Copland, L., Mayer, C., Bishop, M., Luckman, A., Belò, M., & Luckman, A. (2009). Ice velocity and climate variations for Baltoro Glacier, Pakistan. Journal of Glaciology, 55(194), 1061
-
Rowland, C., Balzter, H., Dawson, T., Luckman, A., Patenaude, G., Skinner, L., & Luckman, A. (2008). Airborne SAR monitoring of tree growth in a coniferous plantation. International Journal of Remote Sensing, 29(13), 3873
-
Wright, A., Wadham, J., Siegert, M., Luckman, A., Kohler, J., Nuttall, A., & Luckman, A. (2007). Modeling the refreezing of meltwater as superimposed ice on a high Arctic glacier: A comparison of approaches. Journal of Geophysical Research, 112(F4)
-
Luckman, A., Quincey, D., & Bevan, S. (2007). The potential of satellite radar interferometry and feature tracking for monitoring flow rates of Himalayan glaciers. Remote Sensing of Environment, 111(2-3), 172-181.
-
Kohler, J., James, T., Murray, T., Nuth, C., Brandt, O., Barrand, N., Aas, H., Luckman, A., Luckman, A., & James, T. (2007). Acceleration in thinning rate on western Svalbard glaciers. Geophysical Research Letters, 34(18)
-
Lange, R., Luckman, A., & Murray, T. (2007). Improvement of Satellite Radar Feature Tracking for Ice Velocity Derivation by Spatial Frequency Filtering. IEEE Transactions on Geoscience and Remote Sensing, 45(7), 2309-2318.
-
QUINCEY, D., LUCKMAN, A., HESSEL, R., DAVIES, R., SANKHAYAN, P., BALLA, M., & Luckman, A. (2007). Fine-resolution remote-sensing and modelling of Himalayan catchment sustainability. Remote Sensing of Environment, 107(3), 430-439.
-
Quincey, D., Richardson, S., Luckman, A., Lucas, R., Reynolds, J., Hambrey, M., Glasser, N., & Luckman, A. (2007). Early recognition of glacial lake hazards in the Himalaya using remote sensing datasets. Global and Planetary Change, 56(1-2), 137-152.
-
Bevan, S., Luckman, A., Murray, T., Sykes, H., & Kohler, J. (2007). Positive mass balance during the late 20th century on Austfonna, Svalbard, revealed using satellite radar interferometry. Annals of Glaciology, 46(1), 117-122.
-
Pope, A., Murray, T., & Luckman, A. (2007). DEM quality assessment for quantification of glacier surface change. Annals of Glaciology, 46(1), 189-194.
-
Balzter, H., Luckman, A., Skinner, L., Rowland, C., Dawson, T., & Luckman, A. (2007). Observations of forest stand top height and mean height from interferometric SAR and LiDAR over a conifer plantation at Thetford Forest, UK. International Journal of Remote Sensing, 28(6), 1173-1197.
-
Luckman, A., Murray, T., Lange, R., & Hanna, E. (2006). Rapid and synchronous ice-dynamic changes in East Greenland. Geophysical Research Letters, 33(3)
-
Pritchard, H., Luckman, A., & Murray, T. (2005). Glacier surge dynamics of Sortebræ, east Greenland, from synthetic aperture radar feature tracking. Journal of Geophysical Research, 110(F3)
-
Luckman, A. (2005). Seasonal variation in velocity before retreat of Jakobshavn Isbræ, Greenland. Geophysical Research Letters, 32(8)
-
Wright, A., Wadham, J., Siegert, M., Luckman, A., & Kohler, J. (2005). Modelling the impact of superimposed ice on the mass balance of an Arctic glacier under scenarios of future climate change. Annals of Glaciology, 42(1), 277-283.
-
Suh, C., Sparks, R., Fitton, J., Ayonghe, S., Annen, C., Nana, R., Luckman, A., & Luckman, A. (2005). The 1999 and 2000 eruptions of Mount Cameroon: eruption behaviour and petrochemistry of lava. Bulletin of Volcanology, 67(4), 388-390.
-
Tansey, K., Luckman, A., Skinner, L., Balzter, H., Strozzi, T., Wagner, W., & Luckman, A. (2004). Classification of forest volume resources using ERS tandem coherence and JERS backscatter data. International Journal of Remote Sensing, 25(4), 751-768.
-
Murray, T. & Luckman, A. (2003). Is there a single surge mechanism? Contrasts in dynamics between glacier surges in Svalbard and other regions. Journal of Geophysical Research, 108(B5)
-
Grey, W., Luckman, A., Holland, D., & Luckman, A. (2003). Mapping urban change in the UK using satellite radar interferometry. Remote Sensing of Environment, 87(1), 16-22.
-
Luckman, A., Grey, W., & Luckman, A. (2003). Urban building height variance from multibaseline ERS coherence. IEEE Transactions on Geoscience and Remote Sensing, 41(9), 2022-2025.
-
Wagner, W., Luckman, A., Vietmeier, J., Tansey, K., Balzter, H., Schmullius, C., Davidson, M., Gaveau, D., Gluck, M., Le Toan, T., Quegan, S., Shvidenko, A., Wiesmann, A., Yu, J., & Luckman, A. (2003). Large-scale mapping of boreal forest in SIBERIA using ERS tandem coherence and JERS backscatter data. Remote Sensing of Environment, 85(2), 125-144.
-
Balzter, H., Skinner, L., Luckman, A., Brooke, R., & Luckman, A. (2003). Estimation of tree growth in a conifer plantation over 19 years from multi-satellite L-band SAR. Remote Sensing of Environment, 84(2), 184-191.
-
Murray, T., Luckman, A., Strozzi, T., & Nuttall, A. (2003). The initiation of glacier surging at Fridtjovbreen, Svalbard. Annals of Glaciology, 36(1), 110-116.
-
Luckman, A., Murray, T., Jiskoot, H., Pritchard, H., & Strozzi, T. (2003). ERS SAR feature-tracking measurement of outlet glacier velocities on a regional scale in East Greenland. Annals of Glaciology, 36(1), 129-134.
-
Pritchard, H., Murray, T., Strozzi, T., Barr, S., & Luckman, A. (2003). Surge-related topographic change of the glacier Sortebrae, East Greenland, derived from synthetic aperture radar interferometry. Journal of Glaciology, 49(166), 381-390.
-
Jiskoot, H., Murray, T., & Luckman, A. (2003). Surge potential and drainage-basin characteristics in East Greenland. Annals of Glaciology, 36, 142-148.
-
Luckman, A., Murray, T., & Strozzi, T. (2002). Surface flow evolution throughout a glacier surge measured by satellite radar interferometry. Geophysical Research Letters, 29(23), 10-1-10-4.
-
Strozzi, T., Luckman, A., Murray, T., Wegmüller, U., Werner, C., & Luckman, A. (2002). Glacier motion estimation using SAR offset-tracking procedures. IEEE Transactions on Geoscience and Remote Sensing, 40(11), 2384-2391.
-
McCarroll, D., Pettigrew, E., Luckman, A., Guibal, F., Edouard, J., & Luckman, A. (2002). Blue Reflectance Provides a Surrogate for Latewood Density of High-Latitude Pine Tree Rings. Arctic, Antarctic, and Alpine Research, 34(4), 450
-
Balzter, H., Talmon, E., Wagner, W., Gaveau, D., Plummer, S., Yu, J., Quegan, S., Davidson, M., Toan, T., Gluck, M., Shvidenko, A., Nilsson, S., Tansey, K., Luckman, A., & Schmullius, C. (2002). Accuracy assessment of a large-scale forest cover map of central Siberia from synthetic aperture radar. Canadian Journal of Remote Sensing, 28(6), 719-737.
-
Murray, T., Strozzi, T., Luckman, A., Pritchard, H., & Jiskoot, H. (2002). Ice dynamics during a surge of Sortebræ, East Greenland. Annals of Glaciology, 34, 323-329.
-
Horritt, M., Mason, D., Luckman, A., & Luckman, A. (2001). Flood boundary delineation from synthetic aperture radar imagery using a statistical active contour model. International Journal of Remote Sensing, 22SU Repository: https://cronfa.swan.ac.uk/Record/cronfa34763
-
Luckman, A., Baker, J., Wegmüller, U., & Luckman, A. (2000). Repeat-Pass Interferometric Coherence Measurements of Disturbed Tropical Forest from JERS and ERS Satellites. Remote Sensing of Environment, 73(3), 350-360.
-
Baker, J., Luckman, A., & Luckman, A. (1999). Microwave observations of boreal forests in the NOPEX area of Sweden and a comparison with observations of a temperate plantation in the United Kingdom. Agricultural and Forest Meteorology, 98-99, 389-416.
-
Luckman, A., Baker, J., Honzák, M., Lucas, R., & Luckman, A. (1998). Tropical Forest Biomass Density Estimation Using JERS-1 SAR: Seasonal Variation, Confidence Limits, and Application to Image Mosaics. Remote Sensing of Environment, 63(2), 126-139.
-
Luckman, A. & Luckman, A. (1998). The effects of topography on mechanisms of radar backscatter from coniferous forest and upland pasture. IEEE Transactions on Geoscience and Remote Sensing, 36(5), 1830-1834.
-
Luckman, A. & Luckman, A. (1998). Correction of SAR imagery for variation in pixel scattering area caused by topography. IEEE Transactions on Geoscience and Remote Sensing, 36(1), 344-350.
-
Luckman, A., Frery, A., Yanasse, C., Groom, G., & Luckman, A. (1997). Texture in airborne SAR imagery of tropical forest and its relationship to forest regeneration stage. International Journal of Remote Sensing, 18(6), 1333-1349.
-
Luckman, A., Baker, J., Kuplich, T., Corina da Costa, F., Alejandro, C., & Luckman, A. (1997). A study of the relationship between radar backscatter and regenerating tropical forest biomass for spaceborne SAR instruments. Remote Sensing of Environment, 60(1), 1-13.
-
Da Costa Freitas Yanasse, C., Sant'Anna, S., Frery, A., Rennó, C., Soares, J., Luckman, A., & Luckman, A. (1997). Exploratory study of the relationship between tropical forest regeneration stages and SIR-C L and C data. Remote Sensing of Environment, 59(2), 180-190.
-
Luckman, A., Allinson, N., Ellis, A., Flude, B., & Luckman, A. (1995). Familiar face recognition: A comparative study of a connectionist model and human performance. Neurocomputing, 7(1), 3-27.
-
Luckman, A., Allinson, N., & Luckman, A. (1990). Modelling peripheral pre-attention and foveal fixation for search directed machine vision systems. Proceedings of SPIE - The International Society for Optical Engineering, 1197
-
Luckman, A., Allinson, N., & Luckman, A. (1989). A real-time image acquisition and processing system for a risc-based microcomputer. Proceedings of SPIE - The International Society for Optical Engineering, 1027
Conference Contributions
-
Tansey, K., Balzter, H., Hoscilo, A., Luckman, A., Page, S., & Luckman, A. (2009). Relationships between tropical, temperate and boreal forest variables and palsar data. In European Space Agency, (Special Publication) ESA SPSU Repository: https://cronfa.swan.ac.uk/Record/cronfa32252
-
Luckman, A., Baker, J., & Wegmuller, U. (1998). Repeat-pass interferometric coherence measurements of tropical forest from JERS and ERS satellites. In IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174)IEEE.
-
Luckman, A. & Baker, J. (1997). A simple model for the estimation of biomass density of regenerating tropical forest using JERS-1 SAR and its application to Amazon region image mosaics. In IGARSS'97. 1997 IEEE International Geoscience and Remote Sensing Symposium Proceedings. Remote Sensing - A Scientific Vision for Sustainable DevelopmentIEEE.
-
Luckman, A. & Baker, J. (1995). The contribution of trunk-ground interactions to the SAR backscatter from a coniferous forest. In 1995 International Geoscience and Remote Sensing Symposium, IGARSS '95. Quantitative Remote Sensing for Science and ApplicationsIEEE.
-
Luckman, A., Groom, G., & Baker, J. (1994). Forest age discrimination from texture measures of SAR imagery. In Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing SymposiumIEEE.
Other Research Outputs
-
Bevan, S., Cornford, S., Luckman, A., Hogg, A., Otosaka, I., & Surawy-Stepney, T. (2022). Exploring the sensitivity of modelled sea-level rise projections from the Amundsen Sea Embayment of the Antarctic Ice Sheet to model parameters
Supervision
-
Development of a viscoelastic model of ice shelf dynamics (awarded 2023)
PhDOther supervisor: Prof Bernd Kulessa -
The implications of costly airflows for space-use and movement decisions in birds (awarded 2022)
PhDOther supervisor: Prof Rory WilsonOther supervisor: Prof Emily Shepard
Taught Modules
-
GEC276 Systemau Gwybodaeth Ddaearyddol
A Geographic Information System (GIS) is a computer-based technology for solving problems of a geographical nature ¿ i.e. involving spatial relationships between people, places and objects. It can be applied to a wide range of disciplines within geography and has developed to provide a means to quickly and professionally produce maps from geospatial data. This module provides a basic grounding in GIS from the nature of spatial information, through the use of GIS in social and physical geography contexts, to the application of computers to solving complex geographical problems. Most importantly, it allows hands-on experience in using Quantum GIS (QGIS), the leading open-source GIS software package, and therefore provides a valuable skill for research and the for workplace.
-
GEG276 Introduction to Geographic Information Systems
A Geographic Information System (GIS) is a computer-based technology for solving problems of a geographical nature ¿ i.e. involving spatial relationships between people, places and objects. It can be applied to a wide range of disciplines within geography and has developed to provide a means to quickly and professionally produce maps from geospatial data. This module provides a basic grounding in GIS from the nature of spatial information, through the use of GIS in social and physical geography contexts, to the application of computers to solving complex geographical problems. Most importantly, it allows hands-on experience in using Quantum GIS (QGIS), the leading open-source GIS software package, and therefore provides a valuable skill for research and the for workplace.
-
GEG278 Dissertation Preparation Skills
This module builds upon student knowledge of social research methods and environmental methods (delivered in GEG277) through to the formulation of a dissertation proposal. The module focuses on key dissertation planning and preparation skills.
-
GEG331 Dissertation Report: Geography
The dissertation is an original, substantive and independent research project in an aspect of Geography. The dissertation research project is based on 20 - 25 days of primary research (e.g fieldwork, lab work, archive work) and several months of analysis and write-up. The end result must be less than 10,000 words of text. The dissertation offers you the chance to follow your personal interests and to demonstrate your capabilities as a Geographer. During the course of your dissertation, you will be supported by a peer-led discussion group and a staff supervisor. Lectures and guidance are delivered via this module and peer and staff led Dissertation Support Groups are delivered via GEG332. Participating in Dissertation Support Groups is vital, and is assessed and, in these groups, students will provide constructive criticism to fellow students undertaking related research projects, learning from their research problems and subsequent solutions. This support and supervision is delivered through GEG332, which is a co- requisite.
-
GEG332 Dissertation Support: Geography
This module provides structured, student-led peer-group support and academic staff group supervision for students undertaking the 30-credit 'Dissertation Report: Geography' module. This support and supervision is assessed through the submission of the Dissertation Outline and the Dissertation Support Group Reflection and Attendance Log. Working within a supervised Student Peer Group, students have the opportunity to provide constructive criticism to fellow students undertaking related research projects, learning from their research problems and subsequent solutions. Group sessions are the main support provision as student¿s work through their Dissertation. This module complements the 'Dissertation Report: Geography' module, which is a co-requisite.
-
GEG344 The Cryosphere in a Changing Climate
This module will provide you with the scientific basis to understand the physical behaviour of glacier ice in our changing climate. We will look at spatial scales ranging from individual ice crystals to continental-scale glaciation. The module core topics will include glacier mass balance, transformation of snow to ice, glacier hydrology, glacier dynamics, ice crystal structure and deformation, glacier sliding, deformation of glacial sediments, glacier flow instabilities and glacier surging. We will introduce example topics of current research interest. The module is assessed through examination, as well as group presentation on a seminar and a short individual report.
-
GEGM22 Geographical Information Systems
Delivery of teaching will be live. Assessment will be self-directed activities and an online test. This module is available to all postgraduate students within the Faculty of science and engineering, Medicine and Human and Health Sciences. Student should be familiar with basic computing and will benefit from numeracy skills.
Career History
-
Professor, Department of Geography, College of Science
2013 - Present
-
Reader, College of Science, Swansea University
2007 - 2013
-
Senior Lecturer, College of Science, Swansea University
2003 - 2007
-
Lecturer (50% RCUK-funded), College of Science
1997 - 2003
-
Higher Scientific Officer, British National Space Centre
1992 - 1997
-
Visiting Lecturer, Institute of Computer Science, University of Nairobi, Kenya
1991 - 1991
-
Research Assistant, Department of Electronics, University of York
1990 - 1991
Research Groups
Glaciology Group
A research group dedicated to furthering knowledge in the quantification of the past and future contribution from glaciers and ice sheets to sea-level rise; the processes driving the present rapid and dramatic changes observed in glaciers, and the instabilities inherent in glacial systems; and the record of palaeo-ice mass instabilities and the processes that drove these changes.