Sept 9 2014 dye release with Dr. Harper Simmons


Arctic Tracer Release Experiment (ARCTREX): Applications for Mapping Spilled Oil in Arctic Waters

ARCTREX preliminary science plan, 2014 cruise

Day 1 (Sept 5, 2014 - depending on weather): Preparation

We will board the Norseman II in Prudhoe Bay, after flying from Fairbanks to Deadhorse. While the ship steams towards our dye release site in the Chukchi Sea, ~100 nm due west of Wainwright, we will unpack and activate the science systems. Once west of Barrow, we might tow the Acrobat while approaching the site in order to locate the major front systems.

Preparations include:

Day 2: Survey

First, three of the gliders will be deployed. Two of the gliders are dedicated to passive acoustic monitoring of marine mammals for a different project, and those will swim away. A third glider (not equipped with a Rhodamine fluorometer) will be used to measure broad-scale hydrography, so it will also swim away. The fourth glider is our go-to "dye glider".

Next, we will survey the study area to prepare for the dye release. Two surface drifters will be deployed and the shipboard ADCP data will be analysed to gain information about surface currents and direction. Pre-release surveys using the Acrobat and through-flow system will help characterize the stratification and T-S properties, and will determine the background levels of chlorophyll-a and other natural signals that might occur in the Rhodamine spectral peak. We will perform repeated microstructure profiles using the microstructure system. This is all designed to inform us where to release the dye in the water column and where we can expect the dye to go (i.e. where "downstream" is).

Day 2 or 3: Dye Release

The first dye release will be a surface release in the middle of mixed layer (~ 7 m depth). The Rhodamine-WT dye patch will be seeded with all 30 drifters. The fourth glider will be positioned downstream of dye patch, and it will remain on station, continuously profiling the water column. On the ship, we will begin profiling with the VMP, perform towed Acrobat surveys, and determine the extent of dye patch (in 2D). The dye patch extent will be provided to NOAA ERMA.

Day 3-6: Plume Evolution

We will track the dye over time and space, with intermittent microstructure profiling. During this time, we will provide frequent updates to NOAA and the Coast Guard, and post daily "science blog" updates to BOEM. Refining the data collection proceedures and pathways will be the goal during this time.

Day 6: Decision

On Day 6, we will evaluate the progress of the first dye release experiment. If the dye is dissipated and there is sufficient time remaining in the cruise, we will try to conduct a second release.

Day 6-10: Completion

If we perform the second release, we will first recover all the satellite-tracked drifters in order to re-deploy them during the new experiment. We may choose to conduct the second dye injections in the bottom boundary layer from a fixed anchored location. The dye solution will be mixed with propanol to achieve the anticipated in situ density. Once again, we will track dye and perform updates of its extent.

Alternatively, if a second dye release is not deemed possible (because of time, weather, etc.), then we will continue to perform post-dye release surveys using the Acrobat and the microstructure system.

Either way, the last day will be spent recovering the drifters and gliders, packing up, and transiting to Wainwright, where we will disembark.