Le corps professoral

Alexandre Roy


Télédétection appliquée aux sciences de l'environnement

Cours enseignés


Post-Doctorat en géographie, Université de Montréal

Post-Doctorat en télédétection, Université de Sherbrooke / Environnement Canada

Microprogramme de 3e cycle en pédagogie de l'enseignement supérieur, Université de Sherbrooke

Doctorat en télédétection, Université de Sherbrooke

Maîtrise en environnement, Université de Sherbrooke

Baccalauréat en géographie physique, Université de Montréal

Intérêts de recherche

- Télédétection des milieux nordiques

- Changement climatique

- Interactions sol, neige, végétation

- Flux de carbone

- Mesures terrains et validation in situ 

Quelques communications et publications



Alijani, Z., Meloche, J., McLaren, A., Lindsay, J., Roy, A., Berg, A. (2022) a comparison of three surface roughness characterization techniques: photogrammetry, pin profiler and smartphone-based LiDAR, International Journal of Digital Earth, 10.1080/17538947.2022.2160842

Assani, A.A., Zeroual, A., Kinnard, C., Roy, A (2022) Spatial-temporal variability of seasonal daily minimum flows in southern Québec: synthesis on the impacts of climate, agriculture and wetlands, Hydrology Research, 10.2166/nh.2022.070.

Bussières, S.*, Kinnard, C., Clermont, M., Campeau, S., Dubé-Richard, D.*, Bordeleau, P.-A., Roy, A. (2022) Monitoring water turbidity in a temperate floodplain using UAV : Potential and challenges, Canadian Journal of Remote Sensing, doi.org/10.1080/07038992.2022.2096580.

Bayle, A., Roy, A., Dediue, J.-P., Boudreau, S., Choler, P., Lévesque, E. (2022) Two distinct waves of greening in northeastern Canada: summer warming does not tell the whole story, Environmental Research Letters, 17, 064051.

El-Amine, M.*, Roy, A., Koebsch, F., Baltzer, J., Barr, A., Black, A., Ikawa, H., Iwata, H., Kobayashi, H., Ueyama, M., Sonnentag, O. (2022) What explains the year-to-year variation in the start and end of the photosynthetic growing season of boreal black spruce forests?, Agricultural and Forest Meteorology, 324, 109113.




Zhao, T., Cosh, M. H., Roy, A., Mu, X., Qiu, Y., Shi, J. (2021) Remote sensing experiments for earth system science, International Journal of Digital Earth, 14, 1237-1242.

Royer, A., Roy, A., Jutras, S., Langlois, A. (2021) Performance assessment of radiation-based field sensors for the water equivalent of snow cover (SWE). The Cryosphere, 15, 5079-5098.

Assani, A. A., Zeroual, A., Roy, A., Kinnard, C. (2021) Impacts of agricultural areas on spatio-temporal variability of daily minimum extreme flows during the transitional seasons (spring and fall) in southern Québec, Water, 13, 3487.

Muzalevskiy, K., Ruzicka, Z., Roy, A., Loranty, M., Vsiliev, A. (2021) The classification of frozen/thawed surface state of Arctic soil based on SMAP and GCOM-W1 brightness temperature observations at 1.4 GHz and 6.9 GHz, International Journal of Remote Sensing, 12, 1073-1081.

Letcher, T., Vuyovich, C., Roy, A., Langlois, A. (2021) Improving the understanding and uncertainty of snow radiative transfer modeling using snowpack information of varying complexity, Journal of Selected Topics on Applied Earth Observations in Remote Sensing, 14, 8225-8235.

Royer, A., Domine, F., Roy, A., Langlois, A, Marchand, N., Davesne, G. (2021) New northern snowpack classification linked to vegetation cover on a latitudinal mega-transect across Northeastern Canada, Ecoscience, https://doi.org/10.1080/11956860.2021.1898775.

Pierrat, Z., Nehemy, M.F., Roy, A., Magney, T., Parazoo, N., Laroque, C., Pappas, C., Sonnentag, O., Grossman, K., Bowling, D.R., Seibt, U., Ramirez, A., Johnson, B., Helgason, W., Barr, A., Stutz, J. (2021) Tower-based remote sensing reveals mechanisms behind a two-phased spring transition in a mixed species boreal forest, Journal of Geophysical Research: Biogeosciences, 10.1029/2020JG006191.

Mavrovic, A.*, Lara, R.P., Berg, A., Demontoux, F., Royer, A., Roy, A. (2021) Soil dielectric characterization at L-band microwave frequencies during freeze/thaw transitions, Hydrology and Earth System Sciences, 25, 1117-1131.

Holtzman, N**, Anderegg, L.D.L, Kraatz, S., Mavrovic, A.*, Sonnentag, O., Pappas, C., Cosh, C.H., Langlois, A., Lakhankar, T., Tesser, D., Steiner, N., Colliander, A., Roy, A., Konings, A. (2021) L-band vegetation optical depth as an indicator of plant water potential in a temperate deciduous forest stand, Biogeosciences, 18, 739-753.




Colliander, A., Cosh, M.H., Kelly, V.R., Kraatz, S., Bourgeau-Chavez, L., Siquiera, P., Roy, A., Konings, A.G., Holtzman, N., Misra, S., Entekhabi, D., O’Neill, P., Yueh, H.Y. (2020) SMAP detects soil moisture under temperate forest canopies, Geophysical Research Letters, 47, e89697.

Roy, A., Toose, P., Mavrovic, A.*, Pappas, C., Royer, A., Derksen, C., Berg, A., Rowlandson, T., El-Amine, M*, Helgason, W., Barr, A., Langlois, A., Sonnentag, O. (2020) L-band response to freeze/thaw in a boreal forest stand from ground and tower-based radiometer observations, Remote Sensing of Environment, 237, 111542.

Pappas, C., Maillet, J., Rakowski, S., Baltzer, J., Barr, A., Black, A, Fatichi, S., Laroque, C., Matheny, A, Roy, A., Sonnentag, O., Zha, T. (2020) Aboveground tree growth is a minor and decoupled fraction of boreal forest carbon input, Agricultural and Forest Meteorology, 290, 108030.

Langlois, A., Royer, A., Montpetit, B., Roy, A., Durocher, M. (2020) Snow grain size and shape distributions in northern Canada, Frontiers in Earth Science, 7, 347.

Rutter, N., Sandells, M.J., Derksen, C., King, J., Toose, P., Wake, L., Watts, T., Essery, R., Roy, A., Royer, A., Marsch, P., Larsen, C., Sturm, M. (2020) Effect of snow microstructure variability on Ku-band radar snow water equivalent retrievals, The Cryosphere, 13, 3045-3059.

Vargel, C.**, Royer, A., St-Jean Rondeau, O.**, Picard, G., Roy, A., Sasseville, V., Langlois, A. (2020) Arctic and subarctic snow microstructure analysis for microwave brightness temperature simulations, Remote Sensing of Environment, 242, 111754.




Mavrovic, A.*, Madore, J.-B., Langlois, A., Royer, A., Roy, A. (2019) Snow liquid water content measurement using an open-ended coaxial probe (OECP), Cold Regions Science and Technology, 171, 102958.

Prince, M.*, Roy, A., Royer, A., Langlois, A. (2019) Timing and spatial variability of fall freezing in boreal forest and its effect on SMAP L-band radiometer measurements, Remote Sensing of Environment, 231, 111230.



Marchand, N.**, Royer, A., Krinner, G., Roy, A., Langlois, A. (2018) Snow-covered ground-temperature retrieval in Canadian arctic permafrost areas using a land surface scheme informed with satellite remote sensing data, Remote Sensing, 10, 1703.

Larue, F.**, Royer, A., De Sève, D., Roy, A., and Cosme, E. (2018) Assimilation of passive microwave AMSR-2 satellite observations in a snowpack evolution model over North-Eastern Canada, Hydrology and Hearth System Sciences, 22, 5711-5734.

Prince, M.*, Roy, A., Brucker, L., Royer, A., Kim, Y., and Zhao, T. (2018) Northern hemisphere surface freeze/thaw product from Aquarius L-band radiometers, Earth System Science Data, 10, 2055-2067

Roy, A., Leduc-Leballeur, M., Picard, G., Royer, A., Toose, P., Derksen, C., Lemmetyinen, J., Berg, A., Rowlandson, T., and Schwank, M. (2018) Modelling the L-band snow-covered surface emission in a winter Canadian prairie environment, Remote Sensing, 10, 1451. doi:10.3390/rs10091451

Larue, F.**, Royer, A., De Sève, D., Roy, A., Picard, G., and Vionnet, V. (2018) Simulation and assimilation of passive microwave data using a snowpack model coupled to a calibrated radiative transfer model over Northeastern Canada, Water Resources Research, 54, 10.1029/2017WR022132.

Mavrovic, A.*, Roy, A., Royer, A., Filali, B., Boone, F., Pappas, C., and Sonnentag, O. (2018) Vegetation dielectric characterization in L-band using open-ended coaxial probe, Geoscientific Instruments, Methods and Data Systems, 7, 195-208.

King, J., Derksen, C., Toose, P., Langlois, L., Larsen, C., Lemmetyinen, J., Marsh, P., Montpetit, B., Roy, A., Rutter, N., and Sturm, M. (2018) The influence of snow microstructure on dual-frequency radar measurements in a tundra environment, Remote Sensing of Environment, 215, 242-254.

Wang, P.**, Zhao, T., Shi, J., Hu, T., Roy, A., Qiu, Y., and Lu, H. (2018) Parameterization of freeze/thaw discrimination function algorithm using dense in-situ observation network data, International Journal of Digital Earth, doi.org/10.1080/17538947.2018.1452300.

Rowlandson, T., Berg, A. A., Roy, A., Kim, E., Lara, R. P., Powers, J., Lewis, K., Houser, P., McDonald, K., Toose, P., Wu, A., De Marco, E., Derksen, C., Entin, J., Colliander, A., Xu, X., and Mavrovic, A.* (2018) Capturing agricultural soil freeze/thaw state through remote sensing and ground observations: a soil freeze/thaw validation campaign, Remote Sensing of Environment, 211, 59-70.

Pappas, C., Matheny, A. M., Baltzer, J. L., Barr, A., Andrew, B., Bohrer, G., Detto, M., Maillet, J., Roy, A., Sonnentag, O., and Stephens, J. (2018) Boreal tree hydrodynamics: asynchronous, diverging, yet complementary, Tree Physiology, doi:10.1093/treephys/tpy043.

Saberi, N.**, Kelly, R., Toose, P., Roy, A., and Derksen, C. (2018) Modeling the observed microwave emission from shallow multi-layer tundra snow using DMRT-ML, Remote Sensing, 1327; doi10.3390/rs9121327.s

Lyu, H., McColl, K. A., Li, X., Derksen, C., Berg, A., Black, A. T., Euskirchen, E., Loranty, M., Pulliainen, J., Rautiainen, K., Rowlandson, T., Roy, A., Royer, A., Langlois, A., Stephens, J., Lu, and H., Entekhabi, D. (2018) Validation of the SMAP freeze/thaw product using categorical triple collocation, Remote Sensing of Environment, 205, 329-337.

Williamson, M.**, Rowlandson, T. L., Berg, A. A., Roy, A., Toose, P., Derksen, C., and Tetlock, E. (2018) L-band radiometry freeze/thaw validation using air temperature and ground measurements, Remote Sensing Letters, 9 (4), 403-410.

Montpetit, B., Royer, A., Roy, A., and Langois, A. (2018) In-situ passive microwave emission model parameterization of sub-arctic frozen organic soils, Remote Sensing of Environment, 205, 112-118.




Dolant, C.**, Langlois, A., Brucker, L., Royer, A., Roy, A., and Montpetit, B. (2017) Meteorological inventory of Rain-On-Snow events and detection assessment in the Canadian Arctic Archipelago using microwave radiometry, Physical Geography, DOI: 10.1080/02723646.2017.1400339.

Roy, A., Toose, P., Derksen, C., Rowlandson, T., Berg, A., Lemmetyinen, J., Royer, A., Tetlock, E., Helgason, W, and Sonnentag, O. (2017b) Spatial variability of freeze/thaw L-Band emission over a prairie environment, Remote Sensing, 9, 894, doi:10.3390/rs9090894.

Larue, F.**, Royer, A., De Sève, D., Langlois, A., Roy, A., and Brucker, L. (2017) Validation analysis of the GlobSnow-2 database over an eco-climatic latitudinal gradient in Eastern Canada, Remote Sensing of Environment, 194, 264-277.

Royer, A., Roy, A., Montpetit, B., Saint-Jean-Rondeau, O.**, Picard, G., and Brucker, L. (2017) Comparison of commonly used microwave radiative transfer models for snow remote sensing, Remote Sensing of Environment, 190, 247-259.

Derksen, C., Xu, X., Dunbar, R. S., Colliander, A., Kim, Y., Kimball, J., Black, A., Euskirchen, E., Langlois, A., Loranty, M., Marsh, P., Rautiainen, K., Roy, A., and Royer, A. (2017) Retrieving landscape freeze/thaw state from Soil Moisture Active Passive (SMAP) radar and radiometer measurements, Remote Sensing of Environment, 194, 48-62.

Roy, A., Toose, P., Williamson, M.**, Rowlandson, T., Derksen, C., Royer, A., Berg, A., Lemmetyinen, J., and Arnold, L. (2017a) Response of L-Band brightness temperatures to freeze/thaw and snow dynamics in a prairie environment from ground-based radiometer measurements, Remote Sensing of Environment, 191, 67-80.

Busseau, B.-C.**, Royer, A., Roy, A., Langlois, A., and Domine, F. (2017) Analysis of snow-vegetation interactions in the low Arctic – Subarctic transition zone (north-eastern Canada), Physical Geography., doi.org/10.1080/02723646.2017.1283477, 1-17.

Toose, P., Roy, A., Solheim, F., Derksen, C., Watts, T., Royer, A., and Walker, A. (2017) Radio frequency interference mitigating hyperspectral L-band radiometer, Geoscientific Intruments, Methods and Data Systems, 6, 39-51.

Langlois, A., Johnson, C.-A., Montpetit, B., Royer, A., Richards-Blukacz, A., Neave, E., Dolant, C.**, Roy, A., Arhonditsis, G., Kim, D.-K., Kaluskar, S., and Brucker, L. (2017) Detection of rain-on-snow (ROS) events and ice layer formation using passive microwave radiometry: A context for Peary caribou habitat in the Canadian Arctic, Remote Sensing of Environment, 189, 84-95.


2016 et après

Dolant, C.**, Langlois, A., Montpetit, B., Brucker, L., Roy, A., and Royer, A. (2016) Development of a rain-on-snow detection algorithm using passive microwave radiometry, Hydrological Processes, 30, 3184-3196.

 Lemmetyinen, J., Schwank, M., Rautiainen, K., Parkkinen, T., Mätzler, C., Wiesmann, A., Wegmüller, U., Derksen, C., Toose, P., Roy, A., and Pulliainen, J. (2016) Snow density and ground permittivity retrieved from L-Band radiometry: application to experimental data, Remote Sensing of Environment, 180, 377-391.

Djamai, N.**, Magagi, R., Goïta, K., Olivier, M., Kerr, Y., and Roy, A. (2016) A combination of DISPATCH downscaling algorithm with CLASS land surface scheme for soil moisture estimation at fine scale during cloudy days, Remote Sensing of Environment,184, 1-14.

McColl, K.**, Roy, A., Derksen, C., Konings, A.G., Alemohammed, S.H., and Entekhabi, D. (2016) Triple collocation for binary and categorical variables: application to validating landscape freeze/thaw retrievals, Remote Sensing of Environment, 176, 31-42.

Roy, A., Royer, A, St-Jean-Rondeau, O**, Montpetit, B, Picard, G, Mavrovic, A,* Marchand, N.**, and Langlois, A. (2016) Microwave snow emission modeling uncertainties in boreal and subarctic environments, The Cryopshere, 10, 623-638.

Roy, A., Royer, A., Derksen, C., Brucker, L., Langlois, A., Mialon, A., and Kerr, Y. (2015) Evaluation of spaceborne L-band radiometer measurements for terrestrial freeze/thaw retrievals in Canada, Journal of Selected Topics on Applied Earth Observations in Remote Sensing, 8, 4442-4459.

Courtemanche, B.**, Montpetit, B.**, Royer, A., and Roy, A. (2015) Creation of a lambertian microwave surface for retrieving the downwelling contributionin ground-based radiometric measurements, IEEE Geoscience and Remote Sensing Letters. 12(3), 462-466.

Dupont, F., Picard, G., Royer, A., Fily, M., Roy, A., and Champollion N. (2014) Modeling the microwave emission of bubbly ice; Applications to blue ice and superimposed ice in the Antarctic and Arctic, IEEE Transactions on Geoscience and Remote Sensing, 52(10), 6639-6651.

Roy, A., Royer, A., and Hall, R. (2014) Relationship between forest microwave transmissivity and structural parameters for Canadian boreal forest, IEEE Geoscience and Remote Sensing Letters, 11(10), 1802-1806.

Langlois, A., Bergeron, J., Brown, R., Royer, A., Harvey, R., Roy, A., Wang, L., and Thériault, N. (2014) Evaluation of CLASS 2.7 and 3.5 simulations of snow cover from the Canadian Regional Climate Model (CRCM4) over Québec, Journal of Hydrometeorology, 15, 1325-1343.

Bergeron, J., Royer, A., Turcotte, R., and Roy, A. (2014) Snow cover estimation using blended MODIS and AMSR-E data for improved watershed-scale spring streamflow forecasts in Québec. Hydrological Processes, 28(16), 4626–4639.

Roy, A., Picard, G., Royer, A., Montpetit, B., Dupont, F., Langlois, A., Derksen, C., and Champollion, N. (2013a) Brightness temperature simulations of the Canadian seasonal snowpack driven by measurements of snow specific surface area, IEEE Transactions on Geoscience and Remote Sensing, 51(9), 4692-470.

Montpetit, B., Royer, A., Roy, A., Langlois, A., and Derksen, C. (2013) Snow microwave emission modeling of ice lenses within the snowpack using the Microwave Emission Model for Layered Snowpacks (MEMLS), IEEE Transactions on Geoscience and Remote Sensing, 51(9), 4705-4717.

Picard, G., Brucker, L., Roy, A., Dupont, F., Fily, M., and Royer, A. (2013) Simulation of the microwave emission of multi-layered snowpacks using the dense media radiative transfer theory: the DMRT-ML model, Geoscientific Model Development, 6, 1061–1078.

Roy, A., Royer, A., Montpetit, B., Bartlett, P.A., and Langlois, A. (2013b) Snow specific surface area simulation using the one-layer snow model in the Canadian Land Surface scheme (CLASS). The Cryosphere, 5, 961-975.

Roy, A., Royer, A., Wigneron, J.-P., Langlois, A., Bergeron, J., and Cliché, P. (2012) A simple parameterization for a boreal forest radiative transfer model at microwave frequencies, Remote Sensing of Environment, 124, 371–383.

Montpetit, B., Royer, A., Langlois, A., Cliché, P., Roy, A., Champollion, N., Picard, G., Domine, F., and Obbard, R. (2012) New shortwave infrared albedo measurements for snow specific surface area retrieval, Journal of Glaciology, 58(211), 941-952.

Langlois, A., Royer, A., Dupont, F., Roy, A., Goïta, K., and Picard, G. (2011) Improved corrections of forest effects on passive microwave satellite remote sensing of snow over boreal and subarctic regions, IEEE Transactions on Geoscience and Remote Sensing, 49(10), 3824-3837.

Roy, A., Royer, A., and Turcotte, R. (2010) Analyse de l’identification de la fonte de neige printanière avec QuickSCAT dans le Sud du Québec, Canada, Canadian  Journal of Remote Sensing, 36(2), 89–98.

Roy, A., Royer, A., and Turcotte, R. (2010) Improvement of springtime streamflow in a boreal environment by incorporating snow-covered area derived from remote sensing data, Journal of Hydrology, 390, 35-44.

Turcotte, R., Fortier-Filion, T.-C., Fortin, V., Roy, A., and Royer, A. (2010) Simulations hydrologiques des derniers jours de la crue du printemps : le problème de la neige manquante, Hydrological Science Journal, 55(6), 872-882.


Prix et distinctions