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Alexandre R. Roy

 

Membre régulier

Département des sciences de l’environnement, UQTR

Pavillon Léon-Provancher
3351, boul. des Forges
Trois-Rivières
Québec, Canada
G9A 5H7

819.376.5011 poste 3680
Alexandre.Roy@uqtr.ca

 

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Thèmes de recherche

  • Assimilation de données
  • Changement climatique des régions nordiques
  • Mesure terrains et validation in situ
  • Modélisation hydrologique et biogéophysique (flux de carbone)
  • Télédétection micro-onde des milieux froids
 
 

Étudiants / Chercheurs postdoctoraux au CEN

de Courville, David (Maîtrise). Télédétection de la variation végétale et du verdissement du bassin versant de la rivière Koroc dans le parc national de Kuururjuaq, Nunavik.

Gélinas, Alex (Doctorat). Caractérisation de la permittivité des sols à l’aide d’une sonde coaxiale opérant de 1 à 18 GHz (bandes L à Ku) .

Gorrab ep El Khedhri, Azza (Post-Doctorat). Suivi des traits hydrauliques des arbres à partir des produits de la profondeur optique de la végétation (VOD) issus des observations micro-ondes passives: cas de la forêt boréale.

Hamel Jomphe, Estéban (Doctorat). Évaluation de la végétation dans l'habitat du caribou de Peary par télédétection.

Mavrovic, Alex (Doctorat). Suivi des flux de carbone des régions arctiques par télédétection satellitaire micro-onde multifréquence.

Ortet, Juliette (Doctorat). Mesure et suivi des températures de surface et pergélisol des milieux arctiques par télédétection micro-onde.

Roy, Camille (Maîtrise). Suivi des stratégies hydrauliques d’arbre en forêt boréale à partir de mesures et de modélisation.

Salmabadi, Hesam (Doctorat). Développement de nouveaux produits gel/dégel multicapteurs micro-onde pour l’amélioration du suivi de la saison de croissance en Amérique du Nord.

Sghinolfi, Amedeo (Post-Doctorat). Évaluation de l'impact des changements climatiques sur le patrimoine culturel du Nunavik.

Taghipour Javi, Shahabeddin (Doctorat - Codirection). Influence de l'équivalent en eau de la neige et des conditions de gel du sol sur l'hydrologie printanière dans le domaine agricole dérivée des données radar à synthèse d'ouverture combinées, des observations sur le terrain et de la modélisation hydrologique.

 
 

Thèses et mémoires récents

Crevier, Charlotte , 2022 (Maîtrise - Codirection). Détection des cycles de gel/dégel de la couche active du sol en toundra Arctique à partir d'imageries radar à synthèse d'ouverture (RSO) multicapteur en bande C .

 
 

Communications scientifiques

Bayle, A., Roy, A.R., Dedieu, 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(6), 064051. DOI: 10.1088/1748-9326/ac74d6.

El-Amine, M., Roy, A.R., Koebsch, F., Baltzer, J.L., Barr, A., Black, A., Ikawa, H., Iwata, H., Kobayashi, H., Ueyama, M., Sonnentag, O., 2022. What explains the year-to-year variation in growing season timing of boreal black spruce forests? Agricultural and Forest Meteorology, 324, 109113. DOI: 10.1016/j.agrformet.2022.109113.

Assani, A., Zeroual, A., Roy, A.R., 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 Quebec. Water, 13(24), 3487. DOI: 10.3390/w13243487.

Holtzman, N.M., Anderegg, L.D.L., Kraatz, S., Mavrovic, A., Sonnentag, O., Pappas, C., Cosh, M.H., Langlois, A., Lakhankar, T., Tesser, D., Steiner, N., Colliander, A., Roy, A.R., Konings, A.G., 2021. L-band vegetation optical depth as an indicator of plant water potential in a temperate deciduous forest stand. Biogeosciences, 18(2): 739–753. DOI: 10.5194/bg-18-739-2021.

Letcher, T., Vuyovich, C., Langlois, A., Roy, A.R., 2021. Understanding uncertainty of snow radiative transfer modeling within a mixed deciduous and evergreen forest. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 14: 8225-8235. DOI: 10.1109/JSTARS.2021.3099944.

Mavrovic, A., Pardo Lara, R., Berg, A., Demontoux, F., Royer, A., Roy, A.R., 2021. Soil dielectric characterization during freeze–thaw transitions using L-band coaxial and soil moisture probes. Hydrology and Earth System Sciences, 25: 1117-1131. DOI: 10.5194/hess-25-1117-2021.

Pierrat, Z., Nehemy, M.F., Roy, A.R., Magney, T., Parazoo, N.C., Laroque, C., Pappas, C., Sonnentag, O., Grossmann, 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, 126(5), e2020JG006191. DOI: 10.1029/2020JG006191.

Royer, A., Domine, F., Roy, A.R., Langlois, A., Marchand, N., Davesne, G., 2021. New northern snowpack classification linked to vegetation cover on a latitudinal mega-transect across northeastern Canada. Écoscience, 28(3-4): 225-242. DOI: 10.1080/11956860.2021.1898775.

Royer, A., Roy, A.R., Jutras, S., Langlois, A., 2021. Review article: Performance assessment of radiation-based field sensors for monitoring the water equivalent of snow cover (SWE). The Cryosphere, 15: 5079-5098. DOI: 10.5194/tc-15-5079-2021.

Zhao, T., Cosh, M.H., Roy, A.R., Mu, X., Qiu, Y., Shi, J., 2021. Remote sensing experiments for earth system science. International Journal of Digital Earth, 14(10): 1237-1242. DOI: 10.1080/17538947.2021.1977473.

Colliander, A., Cosh, M.H., Kelly, V.R., Kraaz, S., Bourgeau-Chavez, L., Siquiera, P., Roy, A.R., Konings, A.G., Holtzman, N., Misra, S., Entekhabi, D., O'Neill, P., Yueh, S., 2020. SMAP detects soil moisture under temperate forest canopies. Geophysical Research Letters, 47(19), e2020GL089697. DOI: 10.1029/2020GL089697.

Langlois, A., Royer, A., Montpetit, B., Roy, A.R., Durocher, M., 2020. Presenting snow grain size and shape distributions in northern Canada using a new photographic device allowing 2D and 3D representation of snow grains. Frontiers in Earth Science, 7, 347. DOI: 10.3389/feart.2019.00347.

Mavrovic, A., Madore, J.-B., Langlois, A., Royer, A., Roy, A.R., 2020. Snow liquid water content measurement using an open-ended coaxial probe (OECP). Cold Regions Science and Technology, 171, 102958. DOI: 10.1016/j.coldregions.2019.102958.

Pappas, C., Maillet, J., Rabowski, S., Baltzer, J.L., Barr, A.G., Black, T.A., Fatichi, S., Laroque, C.P., Matheny, A.M., Roy, A.R., 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. DOI: 10.1016/j.agrformet.2020.108030.

Roy, A.R., Toose, P., Mavrovic, A., Pappas, C., Royer, A., Derksen, C., Berg, A., Rowlandson, T., El-Amine, M., Barr, A., Black, 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, 273, 111542. DOI: 10.1016/j.rse.2019.111542.

Vargel, C., Royer, A., Saint-Jean Rondeau, O., Picard, G., Roy, A.R., Sasseville, V., Langlois, A., 2020. Arctic and subarctic snow microstructure analysis for microwave brightness temperature simulations. Remote Sensing of Environment, 242, 11754. DOI: 10.1016/j.rse.2020.111754.

Prince, M., Roy, A.R., Royer, A., Langlois, A., 2019. Timing and spatial variability of fall soil freezing in boreal forest and its effect on SMAP L-band radiometer measurements. Remote Sensing of Environment, 231, 111230. DOI: 10.1016/j.rse.2019.111230.

Rutter, N., Sandells, M.S., Derksen, C., King, J., Toose, P., Wake, L., Watts, T., Essery, R., Roy, A.R., Royer, A., Marsh, P., Larsen, C., Sturm, M., 2019. Effect of snow microstructure variability on Ku-band radar snow water equivalent retrievals. The Cryosphere, 13(11): 3045–3059. DOI: 10.5194/tc-13-3045-2019.

Wang, P., Zhao, T., Shi, J., Hu, T., Roy, A.R., Qiu, Y., Lu, H., 2019. Parameterization of the freeze/thaw discriminant function algorithm using dense in-situ observation network data. International Journal of Digital Earth, 12(8: The Arctic and High Altitude Mountain Cold Regions: Sustainable Earth Observations and Climate Change): 980-994. DOI: 10.1080/17538947.2018.1452300.

Dolant, C., Langlois, A., Brucker, L., Royer, A., Roy, A.R., Montpetit, B., 2018. Meteorological inventory of rain-on-snow events in the Canadian Arctic Archipelago and satellite detection assessment using passive microwave data. Physical Geography, 39(5): 428-444. DOI: 10.1080/02723646.2017.1400339.

King, J., Derkson, C., Toose, P., Langlois, A., Larsen, C., Lemmetyinen, J., Marsh, P., Montpetit, B., Roy, A.R., Rutter, N., Sturm, M., 2018. The influence of snow microstructure on dual-frequency radar measurements in a tundra environment. Remote Sensing of Environment, 215: 242-254. DOI: 10.1016/j.rse.2018.05.028.

Larue, F., Royer, A., DeSève, D., Roy, A.R., Cosme, E., 2018. Assimilation of passive microwave AMSR-2 satellite observations in a snowpack evolution model over northeastern Canada. Hydrology and Earth System Sciences, 22(11): 5711-5734. DOI: 10.5194/hess-22-5711-2018.

Larue, F., Royer, A., DeSève, D., Roy, A.R., Picard, G., Vionnet, V., Cosme, E., 2018. Simulation and assimilation of passive microwave data using a snowpack model coupled to a calibrated radiative transfer model over North‐Eastern Canada. Water Resources Research, 54(7): 4823-4848. DOI: 10.1029/2017WR022132.

Lyu, H., McColl, K.A., Li, X., Derksen, C., Berg, A., Black, T.A., Euskirchen, E., Loranty, M.M., Pulliainen, J., Rautiainen, K., Rowlandson, T., Roy, A.R., Royer, A., Langlois, A., Stephens, J., Lu, H., Entekhabi, D., 2018. Validation of the SMAP freeze/thaw product using categorical triple collocation. Remote Sensing of Environment, 205: 329-337. DOI: 10.1016/j.rse.2017.12.007.

Marchand, N., Royer, A., Krinner, G., Roy, A.R., Langlois, A., Vargel, C., 2018. Snow-covered soil temperature retrieval in Canadian Arctic permafrost areas, using a land surface scheme informed with satellite remote sensing data. Remote Sensing, 10(11), 1703. DOI: 10.3390/rs10111703.

Mavrovic, A., Roy, A.R., Royer, A., Filali, B., Boone, F., Pappas, C., Sonnentag, O., 2018. Dielectric characterization of vegetation at L band using an open-ended coaxial probe. Geoscientific Instrumentation, Methods and Data Systems, 7(3): 195-208. DOI: 10.5194/gi-7-195-2018.

Montpetit, B., Royer, A., Roy, A.R., Langlois, A., 2018. In-situ passive microwave emission model parameterization of sub-arctic frozen organic soils. Remote Sensing of Environment, 205: 112-118. DOI: 10.1016/j.rse.2017.10.033.

Pappas, C., Matheny, A.M., Baltzer, J.L., Barr, A.G., Black, T.A., Gil, B., Detto, M., Maillet, J., Roy, A.R., Sonnentag, O., Stephens, J., 2018. Boreal tree hydrodynamics: asynchronous, diverging, yet complementary. Tree Physiology, 38(7): 953-964. DOI: 10.1093/treephys/tpy043.

Prince, M., Roy, A.R., Brucker, L., Royer, A., Kim, Y., Zhao, T., 2018. Northern Hemisphere surface freeze–thaw product from Aquarius L-band radiometers. Earth System Science Data, 10(4): 2055-2067. DOI: 10.5194/essd-10-2055-2018.

Rowlandson, T.L., Berg, A.A., Roy, A.R., Kim, E., Pardo Lara, R., Powers, J., Lewis, K., Houser, P., McDonald, K., Toose, P., Wu, A., De Marco, E., Derkson, C., Entin, J., Colliander, A., Xu, X., 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. DOI: 10.1016/j.rse.2018.04.003.

Roy, A.R., Leduc-Leballeur, M., Picard, G., Royer, A., Toose, P., Dersken, C., Lemmetyinen, J., Berg, A., Rowlandson, T., 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.

Williamson, M., Rowlandson, T.L., Berg, A.A., Roy, A.R., Toose, P., Derksen, C., Arnold, L., Tetlock, E., 2018. L-band radiometry freeze/ thaw validation using air temperature and ground measurements. Remote Sensing Letters, 9(4): 403-410. DOI: 10.1080/2150704X.2017.1422872.

Busseau, B.-C., Royer, A., Roy, A.R., Langlois, A., Domine, F., 2017. Analysis of snow-vegetation interactions in the low Arctic-Subarctic transition zone (northeastern Canada). Physical Geography, 38(2): 159-175. DOI: 10.1080/02723646.2017.1283477.

Derksen, C., Xu, X., Dunbar, R.S., Colliander, A., Kim, Y., Kimball, J.S., Black, T.A., Euskirchen, E., Langlois, A., Loranty, M.M., Marsh, P., Rautiainen, K., Roy, A.R., Royer, A., Stephens, J., 2017. Retrieving landscape freeze/thaw state from Soil Moisture Active Passive (SMAP) radar and radiometer measurements. Remote Sensing of Environment, 194: 48-62. DOI: 10.1016/j.rse.2017.03.007.

Langlois, A., Johnson, C.-A., Montpetit, B., Royer, A., Blukacz-Richards, E.A., Neave, E., Dolant, C., Roy, A.R., Arhonditsis, G., Kim, D.-K., Kaluskar, S., 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. DOI: 10.1016/j.rse.2016.11.006.

Larue, F., Royer, A., DeSève, D., Langlois, A., Roy, A.R., Brucker, L., 2017. Validation of GlobSnow-2 snow water equivalent over Eastern Canada. Remote Sensing of Environment, 194: 264-277. DOI: 10.1016/j.rse.2017.03.027.

Roy, A.R., Toose, P., Derksen, C., Rowlandson, T., Berg, A.A., Lemmetyinen, J., Royer, A., Tetlock, E., Helgason, W., Sonnentag, O., 2017. Spatial variability of L-band brightness temperature during freeze/thaw events over a prairie environment. Remote Sensing, 9(9): 894. DOI: 10.3390/rs9090894.

Roy, A.R., Toose, P., Williamson, M., Rowlandson, T., Derksen, C., Royer, A., Berg, A.A., Lemmetyinen, J., Arnold, L., 2017. 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. DOI: 10.1016/j.rse.2017.01.017.

Royer, A., Roy, A.R., Montpetit, B., Saint-Jean Rondeau, O., Picard, G., Brucker, L., Langlois, A., 2017. Comparison of commonly-used microwave radiative transfer models for snow remote sensing. Remote Sensing of Environment, 190: 247-259. DOI: 10.1016/j.rse.2016.12.020.

Saberi, N., Kelly, R., Toose, P., Roy, A.R., Dersken, C., 2017. Modeling the observed microwave emission from shallow multi-layer tundra snow using DMRT-ML. Remote Sensing, 9(12), 1327. DOI: 10.3390/rs9121327.

Toose, P., Roy, A.R., Solheim, F., Derksen, C., Watts, T., Royer, A., Walker, A., 2017. Radio-frequency interference mitigating hyperspectral L-band radiometer. Geoscientific Instrumentation, Methods and Data Systems, 6(1): 39-51. DOI: 10.5194/gi-6-39-2017.

Dolant, C., Langlois, A., Montpetit, B., Brucker, L., Roy, A.R., Royer, A., 2016. Development of a rain-on-snow detection algorithm using passive microwave radiometry. Hydrological Processes, 30(18): 3184-3196. DOI: 10.1002/hyp.10828.

Roy, A.R., Royer, A., St-Jean-Rondeau, O., Montpetit, B., Picard, G., Mavrovic, A., Marchand, N., Langlois, A., 2016. Microwave snow emission modeling uncertainties in boreal and subarctic environments. The Cryosphere, 10(2): 623-638. DOI: 10.5194/tc-10-623-2016.

Courtemanche, B., Montpetit, B., Royer, A., Roy, A.R., 2015. Creation of a lambertian microwave surface for retrieving the downwelling contribution in ground-based radiometric measurements. IEEE Transactions on Geoscience and Remote Sensing, 12(3): 462-466. DOI: 10.1109/LGRS.2014.2346138.

Roy, A.R., Royer, A., Derksen, C., Brucker, L., Langlois, A., Mialon, A., Kerr, Y.H., 2015. Evaluation of spaceborne L-band radiometer measurements for terrestrial freeze/thaw retrievals in Canada. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 8(9): 4442-4459. DOI: 10.1109/JSTARS.2015.2476358.

Bergeron, J., Royer, A., Turcotte, R., Roy, A.R., 2014. Snow cover estimation using blended MODIS and AMSR-E data for improved watershed-scale spring streamflow simulation in Quebec, Canada. Hydrological Processes, 28: 4626-4639. DOI: 10.1002/hyp.10123.

Dupont, F., Picard, G., Royer, A., Fily, M., Roy, A.R., Langlois, A., 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. DOI: 10.1109/TGRS.2014.2299829.

Langlois, A., Bergeron, J., Brown, R., Royer, A., Harvey, R., Roy, A.R., Wang, L., Thériault, N., 2014. Evaluation of CLASS 2.7 and 3.5 simulations of snow properties from the Canadian Regional Climate Model (CRCM4) over Québec, Canada. Journal of Hydrology, 15(4): 1325-1343. DOI: 10.1175/JHM-D-13-055.1.

Roy, A.R., Royer, A., Hall, R.J., 2014. Relationship between forest microwave transmissivity and structural parameters for the canadian boreal forest. IEEE Transactions on Geoscience and Remote Sensing, 11(10): 1802-1806. DOI: 10.1109/LGRS.2014.2309941.

 
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