Blog from the RV Polarstern: MOSAiC trace gas fluxes update 5.0

By Byron Blomquist

Since leaving the Tryoshnikov about 3 days ago at the start of Leg 5, we have been making rapid progress to the north in broken ice and open water, averaging about 6 knots. Over the past couple weeks the icepack north of Greenland thinned and opened considerably - this sea ice map (right) shows the ship's current position near 87N, 20W. Extensive ice loss in this sector is highly unusual, but this year is shaping up to be among the lowest in overall sea ice extent at the summer minimum. We hope to locate the Leg 5 ice camp an area with full ice cover, perhaps near 87N, 45E. The transit may take us very close to the North Pole and back to the area along the Leg 2 drift track.

Conditions for shipboard gas and aerosol measurement systems are very good, with winds directly on the bow at 5-10 m/s. All the flux and trace gas instruments have been running, and measurements along the transect from ~ 80N to the pole will be interesting. Over the past two days we've seen the atmospheric DMS concentration drop from several hundred ppt to less than 10 ppt. This reinforces the observation from leg 4 of weak DMS emissions from the northerly ice pack. The ice at 86N appears to have much less Melosira algae or other signs of biological activity compared to the Leg 4 ice camp or the MIZ at 80N.