ARCTREX is now underway! The science party consisting of Peter Winsor (UAF, PI), Bob Chant (Rutgers), Harper Simmons (UAF), Hank Statscewich (UAF), Eli Hunter (Rutgers), Jack McSweeney (Rutgers), and Pete Shipton (UAF) departed from Fairbanks on an ERA flight to Deadhorse at 11:45 am. Nice flying conditions and good visibility below the cloud deck allowed for an easy touchdown at 1 pm. Sheyna Wisdom (Fairweather) met us at the Deadhorse Aviation Center. We transferred to a bus that took us through the oil fields to West Dock where we did a ship-to-ship transfer to the Norseman II vessel that is going to be our home for the next 10 days.

We had a nice dinner and a safety briefing with deck boss, Scotty, that finished at 8:30 pm. Part of the science gear was loaded, and we moved more science gear around, including drums of Rhodamine dye and propanol and our Acrobat winch. Harper Simmons got his microstructure winch set up on the aft deck. We are now on standby until all the gear arrives. Everyone is anxious to get going and is in good spirits.

Morning started with breakfast and safety meeting. Gear is being loaded on West Dock, and we are waiting for the gear to arrive on the Norseman II. The weather forecast is looking better.

10:10 am: The Alaska Marine Service boat is upside of the NII. Loading of gear onto the NII is starting.

11:10 am: Offloading from AMS to NII is done! We will steam to just offshore of Wainwright and get the drifters onboard tomorrow night using the Tukpuk. ETA is approximately 6 pm tomorrow (Monday, 8th).

9:00 pm: We are steaming towards Wainwright and the dye release location. We are currently at 71° N, 152° W with a beautiful sunset outside and calm seas. Harper has installed the microstructure system, The Rutgers group worked on the the dye release equipment, 3 gliders and the towed Acrobat system were prepped, and we are looking forward to starting science sampling tomorrow. Everyone is excited!

7:30 am: We are still steaming to just offshore of Wainwright to rendezvous with the Westward Wind in order to do a ship-to-ship transfer of ocean drifters.

5:45 pm: We are nearing Wainwright and are currently at 70° 58' N, 159° 6' W. It is overcast with 10 kt winds, and seas are at 4 ft. We are inside the ACC with a balmy SST of 7° C and SSS of 30.8 ppt.

11:00 pm: The 34' vessel Tukpuk from Wainwright with Captain Blair heroically made one last, late run out to meet with the NII and transfer drifters in growing seas at 10 pm. All 30 drifters made it across and were activated on deck for coms check by Jack and Pete. We deployed the towed instrument called the Acrobat and plan to tow it through the night from Wainwright to the dye release site.

We towed the Acrobat system offshore of Wainwright to the dye release site. We saw a really exciting cross section that shows large frontal systems and changes in hydrography as we cut across the Chukchi shelf. We recovered the Acrobat at 16:40 UTC at 71° 10.5' N, 162° 30.8' W.

We prepared our three gliders and all three were deployed in this area. One of the gliders is carrying passive acoustic sensors to monitor marine mammals in real time, a project funded by AOOS and in collaboration with Mark Baumgartner (WHOI) and Kate Stafford (UW). Another glider will do a large-scale hydrographic survey over the next 18 days around the Hanna Shoal area, while the third glider is equipped with a Rhodamine dye fluorometer to help us with mapping the dye.

Dye released! We released ~ 275 gallons of high-concentration Rhodamine dye mixed with alcohol and seawater to gain neutral density. The dye was released at 10:47 UTC at 71° 17.914' N, 162° 39.139' W using a CTD to get the hose down to 7 m depth, the middle of the mixed layer.

The whole injection only took 20 min and was followed by the deployment of 15 drifters drogued at 1 m within the dye patch. The drifters are recording GPS positions at 5 min intervals. At 23:40 pm UTC we started mapping the dye patch with our Acrobat system.

How to track dye? We have had a full exciting day and have tracked the dye using the Norseman II's throughflow water sampling system, which we equipped with a Rhodamine fluorometer, and "mowing the lawn" with our towed Acrobat system. The captain of the ship has to make 50-150 turns per day while we paint a radiator pattern across the ocean with our instruments, in order to map the dye in time and space.

Everyone in the science party onboard is now split into two main groups (day and night shift) in order to sample the dye 24/7. An example plot of a completed dye map is shown below. The dye had a concentration of ~1000 parts per billion (ppb) about an hour after the release, and it has now come down to about 100-200 ppb. Surprisingly, after more than 24 hrs, the dye is still visable to the naked eye. We think this is mainly because of the very clear surface waters. We will continue to survey the dye patch throughout the night and all day tomorrow as it disperses and spreads over time, creating one complete dye map every 2-4 hrs.

We also recovered 16 of our surface drifters so we can reuse them with a potential second dye release. The crew of the Norseman II skillfully scooped up the satellite-tracked drifters in the fading light of the evening. The weather is worsening, with winds constantly around 25 kt and waves that are 5ft high and growing. A big low-pressure system over the Bering Sea is forecasted to create challenging conditions tomorrow, with 35 kt winds and 9 ft waves.

The art of tracking dye is interesting and we keep piloting the ship in complex radiator patterns (see picture!). In the meantime, we are surveying the experiment area 24/7 with an AUV glider that is equipped with a Rhodamine fluorometer, CTD, and three-channel optics. The glider was able to locate the corner of the dye patch and is currently running a repeat 10-km-side triangle pattern around our experiment site.