SIMBA data acquired during IAOOS drifts from the North-Pole to Fram Strait in 2013
|Temporal extent||2013-04-15 -2013-09-21|
|Author(s)||Sennechael Nathalie1, Provost Christine1, Gascard Jean-Claude1, Calzas Michel2, Drezen Christine2, Garracio Magali3|
|Affiliation(s)||1 : Laboratoire LOCEAN-IPSL Sorbonne Université (UPMC, Univ. Paris 6) - CNRS - IRD - MNHN, Paris, France
2 : Division Technique de l'INSU/CNRS
3 : Institut Polaire Francais Paul-Emile Victor (IPEV)
|Note||Equipex IAOOS (Ice Atmosphere Ocean Observing System) (ANR-10-EQPX-32-01)|
|Keyword(s)||sea ice, snow melt, melt pond, false bottom, mass balance, ice topography|
We report continuous observations in the high Arctic (north of 84°N) over the full 2013 summer season at two nearby sites with distinct initial snow depth, ice thickness and altitude with respect to the local ice topography. The two sites subject to similar atmospheric conditions that did not favor strong ice melt showed a contrasted evolution. One site, with an initial thin sea ice (1.40 m) at a low location of the floe, witnessed the formation of a spectacular 1.20 m-deep melt pond, a pond-enhanced erosion of the ice surface and a sudden pond drainage into the ocean. Then, the outpoured fresh water rapidly froze, heated the old ice from below and also acted as a temporary shield from the ocean heat flux while it was progressively ablated through dissolution. Eventually, the site almost recovered its initial ice thickness. In contrast, the other site, with an initial thicker sea ice (1.75 m) at a high location of the floe, did not support any significant melt water and underwent over 0.5 m of continuous basal ablation. The two sites witnessed formation of superimposed and interposed ice. Sea-ice survived summer melt at the two sites which entered the refreezing season with similar snow and ice thicknesses. For the first time, processes associated with the formation of a deep melt pond and subsequent false bottom evolution are continuously documented with ice mass balance instruments.
|Acknowledgments||We are indebted to Sergey Pisarev (Shirshov Institute, Russia) who contributed to deployments of the instruments from the Barneo ice camp at the North Pole in 2013. We also thank the team on board Norwegian ice breaker KV Svalbard and the scientific leader of the under-ice cruise (Hanne Sagen, Nansen Center, Norway) for permitting the recovery of the instruments. We acknowledge support from the ANR EQUIPEX IAOOS project, through ANR-10-EQPX-32-01 grant.|
On both IAOOS2 and IAOOS4 plaforms, the ice instrument is a SIMBA (SAMS Ice Mass Balance for the Arctic ). A SIMBA comprises a GPS and a 5 m long chain cable hanging through air, snow, sea-ice and ocean. The chain comprises solid-state sensors located every 2 cm measuring temperature at approximately 0.18°C accuracy (resolution 1/16°C). The SIMBA also features a heating mode which can be used to discriminate between different media, especially between snow and ice [Jackson et al., 2013].