Ghislain Picard

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Monitoring and understanding plant phenology is important in the context of studies of terrestrial productivity and global change. Vegetation phenology such as dates of onsets of greening up and leaf senescence have been determined by remote sensing using mainly the Normalized Difference Vegetation Index (NDVI). In boreal regions, the results suffer from(More)
—Snow grain size is the snowpack parameter that most affects the microwave snow emission. The specific surface area (SSA) of snow is a metric that allows rapid and reproducible field measurements and that well represents the grain size. However, this metric cannot be used directly in microwave snow emission models (MSEMs). The aim of this paper is to(More)
12 Despite the fact that the specific surface area (SSA) of snow is a crucial variable to 13 determine the chemical and climatic impact of the snow cover, few data are available on 14 snow SSA because current measurement methods are not simple to use in the field or do not 15 have a sufficient accuracy. We propose here a novel determination method based on(More)
—Two electromagnetic models were used to simulate snow emission at L-band from in situ measurements of snow properties collected at Dome C in Antarctica. Two different approaches were used: one based on the radiative transfer theory, and the other on the wave approach. The Soil Moisture Ocean Salinity (SMOS) satellite observations performed at 1.4 GHz (21(More)
Vegetation phenology is affected by climate change and in turn feeds back on climate by affecting the annual carbon uptake by vegetation. To quantify the impact of phenology on terrestrial carbon fluxes, we calibrate a bud-burst model and embed it in the Sheffield Dynamic Global Vegetation Model (SDGVM) in order to perform carbon budget calculations.(More)
—Microwave radiometry has been extensively used in order to estimate snow water equivalent in northern regions. However, for boreal and taiga environments, the presence of forest causes important uncertainties in the estimates. Variations in snow cover and vegetation in northeastern Canada (north of the Québec province) were characterized in a transect from(More)
—Passive microwave remote sensing is extensively used in polar regions to study the cryosphere. To better understand the measured signal above continental ice-covered areas, our objective is to estimate the microwave emission of bubbly-ice surfaces using a physically based multilayer electromagnetic model, i.e., the dense media radiative transfer—multilayer(More)