Dr Ghislain Picard

Ghislain Picard

Research topics

Snow, Climate,
Microwave remote sensing, snow optics, instrumentation
Antarctica, Arctic regions

Current position & CV

Lecturer (Maîtres de conférences, HDR) at LGGE - OSUG - UGA
Detailed CV

Contact Details

Laboratoire de Glaciologie et de Géophysique de l'Environnement
54, rue Molière
38402 - Saint Martin d'Hères cedex
France
Tel: +33 4 76 82 42 45
Fax: +33 4 76 82 42 01
Email: ghislain.picard@univ-grenoble-alpes.fr

News

  • Mai 2017: I've update the surface melt product up to 2017.
  • Nov 2016 to Feb 2017: My 4th Antarctic campaign. I will be on the ASUMA traverse in December, learn more and follow us on the official ASUMA website or (in French) on the blog, Facebook or Twitter.
  • June 2016: The three-year time-series of spectral albedo acquired with Autosolexs at Dome C is published on PANGEA. And the system is still running!
  • Feb 2016: Surface melt data has been updated with summer 2014/2015. See Data
  • IMASAugust 2015 - July 2016: Sabbatical at ACE CRC, in Hobart, TAS, Australia in the sea-ice group.

Publications

List of publications

Selected publications:

  • M. Dumont, L. Arnaud, G. Picard, Q. Libois, Y. Lejeune, P. Nabat, D. Voisin, S. Morin, In situ continuous visible and near-infrared spectroscopy of an alpine snowpack, The Cryosphere, 11, 1091-1110, doi:10.5194/tc-11-1091-2017 2017
  • G. Picard, Libois, Q., and Arnaud, L., Refinement of the ice absorption spectrum in the visible using radiance profile measurements in Antarctic snow, The Cryosphere, doi:10.5194/tc-2016-146, 2016
  • G. Picard, L. Arnaud, J.-M. Panel, S. Morin, Design of a scanning laser meter for monitoring the spatio-temporal evolution of snow depth and its application in the Alps and in Antarctica, The Cryosphere, 10, 1495-1511,doi:10.5194/tc-10-1495-2016, 2016
  • G. Picard, Q. Libois, L. Arnaud, G. Vérin, M. Dumont, Development and calibration of an automatic spectral albedometer to estimate near-surface snow SSA time series, The Cryosphere, 10, 1297-1316, doi:10.5194/tc-10-1297-2016, 2016
    Open dataset: Picard, G et al. (2016): Spectral albedo and derive specific surface area of snow at Dome C, 2012-2015. doi:10.1594/PANGAEA.860945

Ongoing and past projects

PhD Students

  • F. Adodo (PhD student, supervised by F. Rémy (LEGOS) and G. Picard, 2015-2018)
  • M. Belke (PhD student, supervised by F. Dominé (Takuvik, Québec) and G. Picard, 2015-2018)
  • G. Vérin (PhD student, supervised by G. Picard & M. Babin (Takuvik, Québec), 2014-2017)
  • H. Fréville (PhD student, supervised by E. Brun (CNRM-GAME) & G. Picard, 2012-2015)
  • Q. Libois (PhD student, supervised by G. Picard, 2011-2014)
  • F. Dupont (PhD student, supervised by G. Picard & M. Fily (LGGE) & A. Royer (U. Sherbrooke, Quebec), 2010-2013)
  • N. Champollion (PhD student, supervised by G. Picard & M. Fily (LGGE), 2009-2012)
  • L. Brucker (PhD student, supervised by G. Picard & M. Fily (LGGE), 2006-2009)

Instruments

  • Posssum POSSSUM (Profile Of Snow Specific Surface Area Measurement Using SWIR reflectance) measures the specific surface area (SSA, a metrics of the grain size) profile in snow boreholes with a vertical resolution of one centimeter and down to depths of up to 20 m. POSSSUM measure the snow reflectance (albedo) in the short wave infrared (SWIR) at 1310nm to estimate the SSA. It takes max 1 hour to sample a 10 m deep hole! POSSSUM was tested and validated in the Alps (Arnaud et al. 2011) and was used in Antarctica in Dec 2009 for the first time. POSSSUM pictures..., Poster at ISSW 2009
  • Snow laserASSSAP 1&2 (Alpine/Arctic Snow Specific Surface Area) is a light-weight version of POSSSUM designed for the shallow snowpacks (max 2 m) usually found in Alpine and Arctic regions. ASSSAP uses exactly the same principle of measurement as POSSSUM and allows in addition measurements on snow samples like DUFISSS/IceCube. ASSSAP has extensively been used in Antarctica, Greenland, and in the Alps. During the Davos Intercomparison campaign we have confirmed that the accuracy is as good as other technique in sample mode (10%) and stil very good in profile mode (15%). Considering that it takes 10 min to acquire a 1-m profile, ASSSAP is a very efficient method to get accurate SSA and sample the spatial variability.
  • Rugged Laser scanRLS (Rugged Laser Scan ) is an automatic laserscan designed to work at Dome C, even in winter by -80°C. It scans an area of 100m2 every day and allow to monitor snow accumulation, roughness change, sastrugi dynamics and more.

Models

  • DMRT-ML computes the thermal microwave emission of snowpacks, is now available as an open source software. It is based on the Dense Media Radiative Transfer theory. Please use it and contribute to improve this code! More information, documentation and download
  • TARTES computes snow albedo and other optical properties in the visible/near infrared range. It is a great small piece of Python code that merges Kokhanovsky and Zege, (2004) theory and two-stream solution of the radiative transfer equation. For this public release, we improved the model code and prepared a comprehensive documentation to make TARTES as easy-to-use as possible by any snow scientists with or without (strong) snow optics expertise. More information, documentation and download. TARTES can also be used online to compute albedo.

Data

  • Automatic Photography Pauto PAuto is a near-infrared time-lapse photography system installed at Dome C to monitor the surface. It is ideal to reveal the complexity of the accumulation, drift, post-deposition, and crystallation processes. Operating such a camera is quite challenging in Antarctica with extreme low temperatures. The set of daily picture used by Champollion et al. 2013, spanning November 2009 to February 2010 and from January 2011 to February 2013 is can be browsed and downloaded. More recent data are available upon request.
  • Spectral albedo time-series Autosolexs is a spectral albedometer installed at Dome C. It measures upwelling and downwelling irradiance 5 times an hour from which albedo is deduced after a few processing steps. Specific surface area (SSA) has been estimated from these spectra with a precision of about 15%. The dataset spanning December 2012 to April 2015 is available from PANGEA database. More recent data are available on demand.
  • Snow temperature at Dome C. Since December 2006, snow temperature at 40 levels down to 20m is recorded every hour at Dome C. This dataset has been used to interpret microwave data (Brucker et al. 2011). The instrument was build, installed and is maintained by L. Arnaud and E. Lefebvre at LGGE with the unvaluable support of the IPEV through the GLACIOLOGY and CALVA projects. Download snow temperature data at Dome C.
  • Surface melting in Antarctica. surface melt in Antarctica Surface melting occurs every summer on the coasts and shelves in Antarctica. The inter-annual variations of the melt duration or extent are important indicators of the coastal climate variations. Melt events are easily detected using microwave radiometer data that are available since 1979. We processed these data to extract every single melt events in Antarctica at a 25-km resolution and on a daily basis. This dataset is packaged in a convenient format and freely distributed. Download Melt data

    Modeled and observed snow melt (report in French by F. Cyr)
    Toward a finer resolution snow melt product (report in French by B. Montpetit)