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Faculty Image Joel Harper
Office: ISB 405D
Phone: (406) 243-5867
Email: joel@mso.umt.edu
Website: Click Here

 

Current Position:

Associate Professor, Geosciences

Description:

My research is focused on the interactions and feedbacks between the cryosphere and the climate system. This work is motivated by societal need to understand the climate system, project sea level rise, and manage water resources. I employ methods of computer modeling, data analysis, and field instrumentation. My field research is conducted on the Greenland Ice Sheet, small glaciers in Alaska and Montana, and seasonal snow in Montana. My research is funded by the U.S. National Science Foundation, NASA, and the Swedish Nuclear Waste Management Company.

Field Of Study:

Glaciology

Snow Hydrology

Climate Change

Courses:

GEOS 108: Climate Change, Past and Future

GEOS 488: Snow Ice and Climate

GEOS 595: Fundamentals of Academic Research

GEOS 548: Advanced Topics in the Cryosphere

Selected Publications:

Other Publications:

(updated ~1 yr-1)

Meierbachtol, T., J. Harper, and N. Humphrey (2013), Basal drainage system response to increasing surface melt on the Greenland ice sheet, Science, 341(6147), 777–779, doi:10.1126/science.1235905.

Silverman, N. L., M. P. Maneta, S.-H. Chen, and J. T. Harper (2013), Dynamically downscaled winter precipitation over complex terrain of the Central Rockies of Western Montana, USA, Water Resources Research, 49(1), 458–470, doi:10.1029/2012WR012874.

Rennermalm, A., Moustafa, S., Mioduszewski, J., Chu, V., Forster, R., Hagedorn, B., Harper, J., Mote, T., Robinson, D., Shuman, C., Smith, L.., Tedesco, M. (2013), Understanding Greenland ice sheet hydrology using an integrated multi-scale approach, Environmental Research Letters, 8(1), 015017, doi:10.1088/1748-9326/8/1/015017.

Bradford, J. H., J. Nichols, J. T. Harper, and T. Meierbachtol (2013), Compressional and EM wave velocity anisotropy in a temperate glacier due to basal crevasses, and implications for water content estimation, Annals of Glaciology, 54(64), 168–178, doi:10.3189/2013AoG64A206.

Brown, J., J. Bradford, J. Harper, W. T. Pfeffer, N. Humphrey, and E. Mosley-Thompson (2012), Georadar-derived estimates of firn density in the percolation zone, western Greenland ice sheet, Journal of Geophysical Research, 117(F1), F01011, doi:10.1029/2011JF002089.

Harper, J. T., N. Humphrey, W. T. Pfeffer, J. Brown, and X. Fettweis (2012), Greenland ice-sheet contribution to sea-level rise buffered by meltwater storage in firn., Nature, 491(7423), 240–3, doi:10.1038/nature11566.

Humphrey, N. F., J. T. Harper, and W. T. Pfeffer (2012), Thermal tracking of meltwater retention in Greenland’s accumulation area, Journal of Geophysical Research, 117(F1), F01010, doi:10.1029/2011JF002083.

Mikesell, T. D., K. van Wijk, M. M. Haney, J. H. Bradford, H. P. Marshall, and J. T. Harper (2012), Monitoring glacier surface seismicity in time and space using Rayleigh waves, Journal of Geophysical Research, 117(F2), F02020, doi:10.1029/2011JF002259.

Brown, J., J. Harper, W. T. Pfeffer, N. Humphrey, and J. Bradford (2011), High-resolution study of layering within the percolation and soaked facies of the Greenland ice sheet, Annals of Glaciology, 52(59), 35–42.

Brinkerhoff, D. J., T. W. Meierbachtol, J. V Johnson, and J. T. Harper (2011), Sensitivity of the frozen/melted basal boundary to perturbations of basal traction and geothermal heat flux: Isunnguata Sermia, western Greenland, Annals of Glaciology, 52(59), 43–50.

Harper, J., N. Humphrey, W. T. Pfeffer, and J. Brown (2011), Firn Stratigraphy and Temperature to 10 m Depth in the Percolation Zone of Western Greenland, 2007–2009, INSTAAR Occasional Paper, ISSN 0069-(60).

Brown, J., J. Harper, and N. Humphrey (2010), Cirque Glacier Sensitivity to 21st Century Climate Change: Sperry Glacier, Montana, Global and Planetary Change, 74(2), 91–98, doi:10.1016/j.gloplacha.2010.09.001.

Gillan, B. J., J. T. Harper, and J. N. Moore (2010), Timing of present and future snowmelt from high elevations in northwest Montana, Water Resources Research, 46, W01507, doi:10.1029/2009WR007861.

Harper, J. T., J. H. Bradford, N. F. Humphrey, and T. W. Meierbachtol (2010), Vertical extension of the subglacial drainage system into basal crevasses, Nature, 467, 579–582, doi:10.1038/nature09398.

Bradford, J. H., J. T. Harper, and J. Brown (2009a), Complex dielectric permittivity measurements from ground-penetrating radar data to estimate snow liquid water content in the pendular regime, Water Resources Research, 45, 1–12, doi: 10.1029/2008WR007341.

Bradford, J. H., J. Nichols, M. T. D., and J. T. Harper (2009b), Continuous profiles of electromagnetic wave velocity and water content in glaciers, Annals of Glaciology, 50(51), 1–9.

Brown, J., J. Harper, and J. Bradford (2009), A radar transparent layer in a temperate valley glacier: Bench Glacier, Alaska, Earth Surface Processes and Landforms, 34, 1497–1506, doi: 10.1002/esp.1835.

Fudge, T. J., J. T. Harper, N. F. Humphrey, and W. T. Pfeffer (2009), Rapid glacier sliding, reverse ice motion, and subglacial water pressure during an autumn rainstorm, Annals of Glaciology, 50(51), 1–9.

Fudge, T. J., N. F. Humphrey, J. T. Harper, and W. T. Pfeffer (2008), Diurnal fluctuations in borehole water levels: configuration of the drainage system beneath Bench Glacier, Alaska, Journal of Glaciology, 54(185), 297–306, doi 10.3189/002214308784886072.

Meierbachtol, T., J. T. Harper, N. F. Humphrey, J. Shaha, and J. Bradford (2008), Air compression as a mechanism for the under damped slug test response in fractured glacier ice, Journal of Geophysical Research, 113(F04009), 1–14, doi: 10.1029/2007JF000908.

Pfeffer, W. T., J. T. Harper, and S. O’Neel (2008), Kinematic constraints on glacier contributions to 21st-century sea-level rise, Science, 321 (5894), 1340–1343, doi: 0.1126/science.1159099.

Bleha, J. A., and J. T. Harper (2007), Snowmelt water generation in a large mountain basin of northwest montana from a MODIS driven model, in Symposium on Environmental Sensing, vol. 1, edited by M. Gribb, pp. 83–86. , Inland Northwest Research Alliance, Boise, ID.

Harper, J. T., N. F. Humphrey, W. T. Pfeffer, and B. Lazar (2007), Two modes of accelerated glacier sliding related to water, Geophysical Research Letters, 34(12), L12503, doi: 10.1029/2007GL030233.

Moore, J. N., J. T. Harper, and M. C. Greenwood (2007), Significance of trends toward earlier snowmelt runoff, Columbia and Missouri Basin headwaters, western United States, Geophysical Research Letters, 34, L16402, doi:10.1029/2007GL031022.

Bradford, J. H., and J. T. Harper (2006), Measuring complex dielectric permittivity from GPR to estimate liquid water content in snow, Society of Exploration Geophysicists Technical Program, 25, 1352–1356, doi:10.1190/1.2369770, doi:10.1190/1.2369770.

Bradford, J. H., and J. T. Harper (2005), Wavefield migration as a tool for estimating spatially continuous radar velocity and water content in glaciers, Geophysical Research Letters, 32, L08502, doi:10.1029/2004GL021770.

Harper, J. T., N. F. Humphrey, W. T. Pfeffer, T. Fudge, and S. O’Neel (2005), Evolution of subglacial water pressure along a glacier’s length, Annals of Glaciology, 40, 31–36.

Fudge, T. J., J. T. Harper, N. F. Humphrey, W. T. Pfeffer, and Anonymous (2005), Timing and pattern of termination of diurnal water pressure fluctuations: Bench Glacier, Alaska, Annals of Glaciology, 40, 102–106.

Harper, J. T., and J. H. Bradford (2003), Snow stratigraphy over a uniform depositional surface: spatial variability and measurement tools, Cold Regions Science and Technology, 37(3), 289–298.

Harper, J. T., N. F. Humphrey, and Anonymous (2003), High altitude Himalayan climate inferred from glacial ice flux, Geophysical Research Letters, 30(14), 1764–1769, doi:10.1029/2003GL017329.

Harper, J. T., and J. H. Bradford (2002), Spatial variability of snow stratification in the absence of terrain factors, in International Snow Science Workshop, edited by R. Stevens, pp. 1–8, International Snow Science Workshop Canada Inc., Penticton, B.C. Canada.

Harper, J. T., N. F. Humphrey, M. C. Greenwood, and Anonymous (2002), Basal conditions and glacier motion during the winter/spring transition, Worthington Glacier, Alaska, U.S.A, Journal of Glaciology, 48(160), 42–50, doi: 10.3189/172756502781831629.

Marshall, H. P., J. T. Harper, W. T. Pfeffer, and N. F. Humphrey (2002), Depth-varying constitutive properties observed in an isothermal glacier, Geophysical Research Letters, 29(61), 1–4.

Harper, J. T., N. F. Humphrey, W. T. Pfeffer, S. V Huzurbazar, D. B. Bahr, B. C. Welch, and Anonymous (2001), Spatial variability in the flow of a valley glacier: deformation of a large array of boreholes, Journal of Geophysical Research, 106(B5), 8547–8562, doi: 10.1029/2000JB900440.

Pfeffer, W. T., N. F. Humphrey, B. Amadei, J. T. Harper, and W. J. (2000), In-situ stress tensor measured in an Alaskan glacier, Annals of Glaciology, 31, 229–235.

Harper, J. T., N. F. Humphrey, and W. T. Pfeffer (1998a), Crevasse patterns and the strain rate tensor: a high resolution comparison, Journal of Glaciology, 44(146), 68–76.

Harper, J. T., N. F. Humphrey, and W. T. Pfeffer (1998b), Three-dimensional deformation measured in an Alaskan Glacier, Science, 281(5381), 1340–1342.

Jones, L. S., and J. T. Harper (1998), Channel avulsions and related processes, and large-scale sedimentation patterns since 1875, Rio Grande, San Luis Valley, Colorado, Geological Society of America Bulletin, 110(3), 411–421.

Welch, B. C., W. T. Pfeffer, J. T. Harper, and N. F. Humphrey (1998), Mapping subglacial surfaces below temperate valley glaciers using 3-dimensional radio-echo sounding techniques, Journal of Glaciology, 44(146), 164–170.

Harper, J. T., N. F. Humphrey, W. T. Pfeffer, and B. C. Welch (1996), Short wavelength variations in the horizontal velocity field of a valley glacier, in Glaciers, Ice Sheets and Volcanoes, vol. Special Re, edited by S. C. Colbeck, pp. 41–48, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, N.H.

Welch, B. C., W. T. Pfeffer, J. T. Harper, and N. F. Humphrey (1996), A maximum glacier-bed surface obtained by radio-echo sounding, in Glaciers, Ice Sheets and Volcanoes, vol. Special Re, edited by S. C. Colbeck, pp. 105–110, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, N.H.

Harper, J. T., and N. F. Humphrey (1995), Borehole video analysis of a temperate glacier’s englacial and subglacial structure; implications for glacier flow models, Geology, 23(10), 901–904.

Harper, J. T. (1993), Glacier terminus fluctuations on Mount Baker, Washington, U.S.A., 1940-1990, and climatic variations, Arctic and Alpine Research, 25(4), 332–340.