Cryosat: ICE-cruise 2011 blog
An international group of seven sea ice scientists left Longyearbyen on 4 April onboard the Norwegian Coastguard vessel KV Svalbard together with polar bear and ivory gull researchers, heading towards the sea ice north and northeast of Svalbard. With the Norwegian Polar Institute’s brand new EM-bird (called Liv which is a norwegian name and means life) on board, we planned to collect data for the Cryosat-2 cal/val efforts within the CryoVEx project in a region that is not very often visited.
After last year’s summer cruise to the same area, we were particularly interested to see what the ice conditions would be like in spring. This time, the researchers from the Norwegian Polar Institute were joined by scientists from the Dalian Technical University in China, the Nansen Environmental and Remote Sensing Centre in Bergen, the Norwegian Ice Service, and the University of Tromsø.
Despite tighter aviation safety rules leading to stricter tests regarding helicopter operations which delayed the departure, we were out on the ice in the evening of the 5th. The first ice station ever for some of the team brought home right away that we are operating in a rather unforgiving environment: -20°C, strong winds of over 20 knots, snow fall and low visibility made for a cold and tough time on the ice, not the ideal training conditions but good for team building...
The next day brought better conditions and we were off for our first two flights. The ship was positioned close to the track of a Cryosat overpass, and after a short flight along the track in the morning, we were in the air again to measure simultaneously with Cryosat above us. A good first “real” outing for Liv! The flights were complemented by on ice work where a lot of EM31 (ground electromagnetics), snow thickness data, and observations of physical properties of snow and ice were collected. These included snow and ice densities, temperature and salinity profiles through the ice, and detailed snow pits with snow layer and crystal analysis and snow moisture measurements. Along the EM31 lines, we also measure ice thickness and freeboard in drillholes.
Since we shared ship and helicopter with polar bear people, they had the chopper the next couple of days and we stayed in fjord fast ice. The next opportunity for a Cryosat flight came on the 9th, this time also with photography of the ice underneath the helicopter. In sunny but still very windy conditions we covered good ground over the typical ice we found during the entire cruise: lots of large first year ice floes with some nice ridges and nilas and new ice in the leads.
Sharing the helicopter, problems with the bird (teething problems of the new instrument) and a day in Rijpfjorden installing an ice mass balance buoy led to no airborne data for another two days. Instead we gathered data along kilometers of EM31 and snow thickness tracks, valuable ground truth data in a region which probably nobody else will visit this spring.
Cryosat-2 is not the only satellite we are collecting ground truth data for, and on the 12th we finally managed to do a flight concurrent with a high resolution SAR Radarsat-2 qual-pol image. A challenging operation due to heavy ice challenging the ice breaking capabilities of our vessel, and a second helicopter arriving half an hour before the image acquisition time!
The following day, we planned another Cryosat-2 underflight but the weather came in with snow and fog and we were grounded. More time for on ice work! Now, the helicopter has left and we are heading west for a last long ice station before returning to Longyearbyen. By then we will have covered a large part of the region north of Svalbard and gained good insight into the regional conditions.
Embracing all problems and challenges, we managed to get a good dataset to describe the snow and ice cover we found in this remote region. The maiden voyage of Liv, our EM-bird, was a success and we are looking forward to the next cruise starting in 10 days! More Cryosat-2 cal/val activities are waiting for us then and we’ll keep you posted!
Cryosat blog - bio
Angelika Renner is a postdoctoral researcher at the Norwegian Polar Institute (NPI). With a background in both sea ice physics and physical oceanography, she now continues to work in both disciplines and at their interface in NPI’s ICE centre project ICE Fluxes. Focussing on sea ice thickness north of Svalbard and in the Fram Strait, she responsible for running NPI’s EM-bird and is thus involved in CryoVEx.