Arctic Tracer Release Experiment (ARCTREX): Applications for Mapping Spilled Oil in Arctic Waters
ARCTREX Program Objectives
Proposal Abstract
We propose to perform targeted dye release experiments at both the surface and bottom of the Northeast Chukchi Sea to examine applications for mapping spilled oil in Arctic waters. These experiments are designed to test available observational technology, their capability to map a dye plume in time and space, simulating an oil spill, and provide real time data to response agencies, including data for ingestion into numerical oil spill trajectory models. We will utilize existing infrastructure as part of our ongoing ocean observing efforts in the Chukchi Sea, including real-time two-dimensional surface current fields from extended-range high frequency radar, and rely on existing observing assets such as AUV gliders and Acrobat towed vehicle. Using this technology paired with detailed microstructure measurements of ocean turbulence, satellite-tracked surface drifters and dedicated dye measurements using large dynamic-range fluorometers we will attempt to map a dye plume and its evolution in time and space over a 3-7 day period over two field seasons (2014 and 2015) and multiple dye injections. Part of our proposed activities includes evaluating the effectiveness of the suite of instruments to track the released dye under diverse environmental conditions. We will coordinate our field effort with NOAA's Environmental Response Management Application ERMA (Arctic ERMA) and BSEE, and work towards real time data ingestion into their response system.
Objectives
- Conduct at least two field experiments exploring the dispersal and tracking of non-toxic Rhodamine-WT dye off the Chukchi coast in 2014 and 2015
- Deploy AUVs and other sensors in the Chukchi Sea (e.g. HF Radar and drifters for surface currents, ship-based hydrographic measurements), access other available data streams (modeled wind fields, data from meteorological buoys), and integrate the resulting data to assess the fate and transport of the dye plume in real-time
- Display data streams via a web-based mapping tool in near real-time
- Assess the effectiveness of HF Radar and drogued drifters in providing near-surface current input data to oil spill models
- Develop deployment methods and data display techniques for Autonomous Underwater Vehicles (AUVs), customized for use in the Arctic to detect the spatial and temporal evolution of subsurface dye plumes
- Develop a better understanding of the small scale transport processes important to fate and effects modeling used in oil impact analysis
- Develop algorithms quantifying small scale transport processes based on measured oceanographic and meteorological data (i.e., advection, Langmuir circulation, wind drift, vertical and horizontal dispersion coefficients, etc.)
Primary Instrumentation
- VMP-250 Turbulence Profiler:
This will measure hydrographic finestructure and profiles of the thermal and kinetic energy dissipation rates (which quantify the rates of turbulent mixing in the ocean), and will allow us to measure the vertical component of the turbulent mixing and dilution of the Rhodamine dye via a built-in Rhodamine fluorometer.Tethered VMP2000 microstructure profiler already owned and operated by UAF. The VMP250 to be acquired is a lightweight version appropriate to shallow water environments and can be deployed from a small boat. - AUV gliders:
One of our AUV gliders has been outfitted with a Rhodamine-specific fluorometer, in addition to its usual CTD payload. It will return real-time oceanographic data to UAF so the depth-time structure of the dye patch can be displayed in real-time. - High Frequency Radar (HFR):
Although we expect that most of the detailed plume evolution will be sub-HFR grid scale, we can compare surface currents derived from HFR data with fine-scale measurements from surface drifters, and compare effective dispersion with that determined from mapping the dye release plume. - Towed vehicle observations (Acrobat):
The main tool for mapping the dye extent will be a small Acrobat outfitted with a Turner Rhodamine WT fluorometer and a fast-sampling CTD. While it is towed up and down in the water column behind the ship, it will transit data to an onboard deck unit and data-plotting interface, allowing us to adaptively sample the evolving dye plume in time and space.The Acrobat towed vehicle on the aft deck of the Norseman II during August, 2012. The Acrobat is equipped with FastCAT CTD and three-channel Eco Puck sampling at 16 and 8 Hz, respectively.
Associated Links
- Overview of Chukchi Sea Circulation
- ARCTREX 2014 Cruise Plan
- Coastal Mixing & Optics Experiment: synopsis of a dye release experiment by Dr. James Ledwell, WHOI, which is the inspiration for our field program
- Sundermeyer, M. A. and J. R. Ledwell (2001), Lateral dispersion over the Continental Shelf: Analysis of dye-release experiments, J. Geophys. Res., 106 (C5), 9603-9622, doi:10.1029/2000JC900138.