During week three we had another storm passing over us with cold temperatures and strong winds of more than 20 m/s and temperatures that felt like –22 degrees (temperatures of around –11 degree and strong wind). No CTD casts or profiler measurements from the ice were possible due to strong winds and poor visibility. But, we collected acoustic data while drifting fast and used XBT probes to measure sound speed profiles along the cruise track. The EK80 water column data showed signs of increased turbulent mixing.

Lina and Noemie working at the acoustics desk. Photo: Julia Muchowski

Julia Muchowski launching an XBT. Photo: Noemie Planat

The ice at our old position was too thick to make our way northwards therefore we steamed east after the storm had passed, left the ice near Svalbard and steamed up north and back into the ice from there. Our current position is 80 degrees 23.64N and 4 degrees 42.36 E. This morning we moored to an ice floe (the second floe on this expedition) and we will go out this afternoon to collect the first in situ oceanographic data from the ice. The plan is to spend this entire week collecting atmospheric and oceanographic data from the floe, covering an upcoming warm air intrusion.

Photo: Julia Asplund

Greetings, Julia

Ice work, digging holes. Photo: Noemie Planat

Since the beginning of the expedition, we have been busy deploying all instruments and collecting data. The team (composed of Julia, Aileen, and 4 ECS: Anais, Lina, Magnus, Noemie) is in charge of several acoustic instruments (EK80, ADCP (currents), SBP (mapping the subbottom structure), Multibeam (seabed floor) plus oceanographic instruments: CTD (temperature, salinity, depth), rosette and niskin bottles (water samples at depth), UVP and fish camera (which take pictures of e.g. jelly fish, copepods, shrimps and fish), and VMP (high resolution temperature, salinity, and shear profiles).

During last week

• We mapped unmapped seafloor bathymetry, including seamounts and ridges.
• Collected several CTDs. The CTD profiles show large variability in mixed layer depth as well as in structures of temperature and salinity below the mixed layer.
• Acoustic EK80 observations have shown scattering layers around 200-300 m and 500-600 m depth. We use these depths to stop the CTD and film with the fish camera and the UVP
• Helicopter ice stations: we deployed the VMP from a hole in the ice (CTD + shear measurements) at two helicopter stations. One before, and one after a storm. The data show large changes in temperature and salinity.
• Other WPs: ROV underwater multibeam mapping of the ice, surface water samples from leads, ice and snow samples, air measurements (pollution, gas, etc.). Helicopter flights with extensive atmospheric instruments towed. Balloons with soundings launch every 6 hours. Water samples from CTD taken to for instance analyze gas content, isotope ratios.

IB Oden is anchored to ice flows and many work packages deploy instruments on the ice to provide a complete estimate of Ocean-Ice-Air fluxes in the vicinity of the ice floe.

Our WP deploys the VMP microstructure profiler and the fish camera from the ice floe, which will be combined with CTD casts and EK80 acoustic observations. Our goal is to take VMP measurements along a transect across the ice floe, to cover spatial variations in turbulent mixing and stratification of the water below the floe.

The sea ice around us is thick with many ridges which makes it extremely difficult for the Oden to find a path North. In addition, storms keep stopping us from moving north. We are currently at around 79 deg N, 3 deg W and will see in a few days if a path towards the North opens up.

Ice work with IB Oden on the background. Photo: Noemie Plana

CTD work. Photo: Stella Papadopoulou

The first deployment of the microstructure profiler on a helicopter station. Photo: Lina Holthausen

Currently they are in really thick ice at 80 degree 05.44 N and 2 degree 02.58 W, fairly cold with −12.5 degree Celsius. The storm is over and they are preparing for the first ice station next to the ship.

In total, they had 3 successful CTD casts, collected multibeam, subbottom, ADCP and EK80 midwater acoustic data and collected measurements of turbulent mixing on two helicopter ice stations with the microstructure profiler.

Written by Julia Muchowski