Arctic sea ice declines both in extent and volume, at a rate outpacing the ensemble mean of most recent climate model predictions. Observations are key not only to assess ongoing changes, but also to improve our understanding and representation of physical processes that govern heat exchanges between the ocean, ice, and atmosphere, in order to improve the predictive capabilities of climate models. In situ observations are also critical for the calibration and validation of satellite observations which provide a synoptic view of the Arctic. While sea ice extent is now routinely monitored from space, remote sensing of ice thickness is still in its early stage with dedicated missions recently launched (e.g., CryoSat-2 satellite): in-situ data are needed to relate raw measurements to geophysical parameters.
A main objective of the OPTIMISM project is to develop an automated, reasonable cost, system providing real-time measurement not only of ice thickness and conductive fluxes in the ice, but also of radiation, heat and freshwater fluxes at the ocean-ice-atmosphere interfaces, which are needed to assess the sea ice mass balance. These challenging technological developments will build upon the "Ice-T" (for "Ice-Thickness") prototype buoy developed at LOCEAN, intended to both thin and thick ice conditions. The instrument will be deployed for process-oriented studies, motivated or supplemented with numerical modeling works. These works, devoted to the study of coastal polynya of the Svalbard, will focus on the role of ocean mixing and surface energy budget on sea ice evolution and dense water formation. Studies will also focus on wave-ice interactions. Data will as well be collected in the arctic ice pack to contribute to international observational efforts of the Arctic.
This project, initiated in 2009 brings together scientists and engineers from 5 laboratories in France covering the fields of ocean and atmospheric sciences, hydrodynamics, and radar altimetry.
- LOCEAN: Laboratoire d'Oceanographie et du Climat: Experimentation et Approches Numeriques, Paris.
- LATMOS:Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris.
- LHEEA: Laboratoire Hydrodynamique, Energétique et Environnement Atmosphérique, Ecole Centrale de Nantes, Nantes.
- DT-INSU: Division Technique de l'Institut National de Sciences de l'Univers, Meudon et Brest.
- CEN: Centre d'Etudes de la Neige, Meteo France, Grenoble.