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)
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)
The use of listeriaphages as a means of disinfecting contaminated stainless-steel and polypropylene surfaces was investigated. Surfaces artificially contaminated with L. monocytogenes 10401 and 8427 were sanitized with suspensions of listeriaphages (H387, H387-A, and 2671), all belonging to the Siphoviridae family. Phage suspensions at concentrations of up(More)
This paper describes a modeling approach to interpret the C-band synthetic aperture radar (SAR) data from wheat canopies as provided by European Remote Sensing (ERS) satellites, RADARSAT, and the forthcoming Environmental Satellite/Advanced Synthetic Aperture Radar (ENVISAT/ASAR) satellite. At a first step, the results of a first-order modeling were(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)
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)
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)
The Antarctic Plateau presents ideal characteristics to study the relationship between microwave observations and snow/ice properties. It is also a promising target for radiometer calibration and sensor intercalibration, which are critical for applications requiring subkelvin accuracy, such as sea surface salinity retrievals. This paper presents the(More)