Profile

Alex Mavrovic
Ph.D. student
Department of Environmental Sciences
UQTR
Alex.Mavrovic@UQTR.ca

Supervised by:

Alexandre Roy (Regular member)

Oliver Sonnentag (Regular member)

Research project description

Carbon fluxes monitoring of arctic regions using multi-frequency microwave remote sensing

Introduction: Significant uncertainties remain over the impact of snow and vegetation on the evolution of the permafrost thermal regime and it has been shown that those processes are not properly been taken into account in models. It is therefore important to quantify and understand how these carbon pool will evolve with climate change. The difficulty of access, the remoteness and the vastness of the northern environments make their studies challenging. In these isolated regions, microwave remote sensing is a suitable way to monitor these changes since it offers data at high temporal resolution throughout the territory. Microwave remote sensing is a particularly suitable tool for monitoring the state of vegetation and soil because different microwave frequencies have varying levels of penetration depth, which allows retrieving information on the status of these different components. The main objective of my project is to improve carbon flux monitoring in the arctic regions during the winter season using microwave remote sensing. The methodology will first be validated at ground level before using satellite data. Study sites: The simulation work will first be developed on in situ data at Trail Valley Creek (Northwest Territories) and Cambridge Bay (Nunavut) in collaboration with Environment and Climate Change Canada (ECCC) and Université de Sherbrooke. A series of microwave ground radiometers (1.4; 11; 19; 37; 89 GHz) will be deployed at Trail Valley Creek and Cambridge Bay. These instruments will be stationary to obtain time series, but can be mobile to study spatial variability of radiometric measurements. Material and methods: Time series of carbon fluxes will be obtained from Eddy covariance measurements (CO2 fluxes), while mobile carbon flux measurements will be obtained from laboratory analysis of samples collected in the field. Once the methodology has been validated for the ground measurements, the results of the CLASS/CTEM ecosystem model (developed and used by ECCC) will be constrained by satellite microwave data from the Soil Moisture Active Passive (SMAP), SMOS and AMRS2 missions to quantify the importance of the soil thermal regime on carbon fluxes across the Arctic during winter. The various satellite-based radiometers operate at the same frequencies as the ground-based radiometers that will be used for terrestrial measurements. Expected results: By constraining the CLASS / CTEM ecosystem model with radiometric temperature brightness (TB) data, this project aims to improve simulated soil temperatures and thermal regime evolution in tundra soils.

Research Site Coordinates

Scientific Communications

Mavrovic, A., Sonnentag, O., Lemmetyinen, J., Baltzer, J.L., Kinnard, C., Roy, A.R., 2023. <h1>Reviews and syntheses: Recent advances in microwave remote sensing in support of terrestrial carbon cycle science in Arctic–boreal regions</h1>. <strong>Biogeosciences</strong>, 20(14): 2941-2970. DOI: <a href="http://dx.doi.org/10.5194/bg-20-2941-2023" target="_blank">10.5194/bg-20-2941-2023</a>.

Mavrovic, A., Sonnentag, O., Lemmetyinen, J., Voigt, C., Rutter, N., Mann, P., Sylvain, J.-D., Roy, A.R., 2023. Environmental controls of winter soil carbon dioxide fluxes in boreal and tundra environments. <strong>Biogeosciences</strong>, 20(24): 5087-5108. DOI: <a href="http://dx.doi.org/10.5194/bg-20-5087-2023" target="_blank">10.5194/bg-20-5087-2023</a>.

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. <strong>Biogeosciences</strong>, 18(2): 739–753. DOI: <a href="http://dx.doi.org/10.5194/bg-18-739-2021" target="_blank">10.5194/bg-18-739-2021</a>.

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. <strong>Hydrology and Earth System Sciences</strong>, 25: 1117-1131. DOI: <a href="http://dx.doi.org/10.5194/hess-25-1117-2021" target="_blank">10.5194/hess-25-1117-2021</a>.

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). <strong>Cold Regions Science and Technology</strong>, 171, 102958. DOI: <a href="http://dx.doi.org/10.1016/j.coldregions.2019.102958" target="_blank">10.1016/j.coldregions.2019.102958</a>.

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. <strong>Remote Sensing of Environment</strong>, 273, 111542. DOI: <a href="http://dx.doi.org/10.1016/j.rse.2019.111542" target="_blank">10.1016/j.rse.2019.111542</a>.

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. <strong>Geoscientific Instrumentation, Methods and Data Systems</strong>, 7(3): 195-208. DOI: <a href="http://dx.doi.org/10.5194/gi-7-195-2018" target="_blank">10.5194/gi-7-195-2018</a>.

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. <strong>Remote Sensing of Environment</strong>, 211: 59-70. DOI: <a href="http://dx.doi.org/10.1016/j.rse.2018.04.003" target="_blank">10.1016/j.rse.2018.04.003</a>.

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. <strong>The Cryosphere</strong>, 10(2): 623-638. DOI: <a href="http://dx.doi.org/10.5194/tc-10-623-2016" target="_blank">10.5194/tc-10-623-2016</a>.

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