Sound Predictions 2009: The Alaska Ocean Observing System Field Experiment in Prince William Sound - 09.18.2009
How do you predict weather, wind, and waves in one of the most complex marine environments in Alaska? Scientists from several universities, including the University of Alaska Fairbanks, NOAA, and the NASA Jet Propulsion Laboratory put their models to the test from July 19 - August 3, 2009, in Prince William Sound. Mountainous surroundings, notoriously stormy seas, and a complex system of freshwater flows from the land interacting with flows between the Sound and the Gulf of Alaska through a narrow entrance have made modeling the Sound an enormous challenge. The field experiment was part of the development of the Alaska Ocean Observing System (AOOS), which is being designed to deliver both real-time information and long-term trends about Alaska’s ocean conditions and marine life. COSEE-Alaska and COSEE-NOW are assisting with outreach and education about this exciting scientific project. For preliminary results, see http://doc.aoos.org/newsletters/09.09_newsletter_web.pdf.
The experiment began during a summer storm that packed gale-force winds and stormy seas throughout the experiment put the technology and boating operations to the test. A high-frequency radar station ceased working early in the experiment, but repairs were made quickly with the help of a Coast Guard helicopter. Communications were excellent throughout the experiment as scientists found good cell phone connection allowing for data uploads in even remote areas of the Sound.
The need for accurate predictions is underscored by 2009 being the 20th anniversary of the Exxon Valdez oil spill in the Sound. NOAA scientists tested a GNOME model that predicts the trajectory of oil spills. In addition to improved forecasts for oil tankers and being better prepared for oil spill clean-up, improved predictions for waves, winds, and weather will benefit the Sound’s commercial fishing fleet who catch world-famous Copper River red salmon, the Coast Guard’s search-and-rescue operations, recreational boaters, and commercial shippers who bring large amounts of Alaska’s marine freight in and out of Prince William Sound ports.
COSEE Alaska collaborated with COSEE NOW at Rutgers University to produce a “Gazing at the Sea” podcast which will air on public radio in Boston and Alaska. The podcast was based on interviews with from scientists and community members who will benefit from an improved observing system in the Sound. For educators, new lesson plans will make use of “real-time” data from the experiment for learning about Alaska currents, ocean circulation, and the potential effects of climate change on these aspects of Alaska’s seas. For younger children, AOOS is developing lesson plans around a children’s book produced by AOOS, Pete Puffin’s Wild Ride. Pete is a puffin toy dropped off a cruise ship offshore of Alaska by a vacationing child. In the book, Pete rides Alaska’s currents, ending up eventually on the East Coast and the home of the much older child who lost him. Pete will find himself in Prince William Sound during the experiment and, with the help of COSEE Alaska, will blog about his adventures on the AOOS website.
Prince William Sound has 20 weather stations reporting real-time data within an area of 40 square mles, one of the densest networks of observation platforms in the world. This allows predictions on the scale as small as about 7 square miles. Data from these stations are fed into a Weather Research and Forecasting (WRF) developed by the Alaska Experimental Forecast Facility. Meanwhile, the Simulating Waves in the Nearshore (SWAN) model forecasts the height of waves throughout the Sound, accurate to within 500 yards. Ocean circulation in the Sound is driven by an intricate mixture of buoyancy, wind, tidal, and other forces. A third model, the Regional Ocean Modeling System (ROMS) can simulate the behavior of ocean currents, tides, salinity, and temperatures at different scales from that of the Gulf of Alaska down to a resolution of about two square miles within the Sound.
A number of sensors were already in place before the experiment took place - on the upland weather stations, weather buoys, and ocean-ographic moorings (anchored to the ocean floor). High-frequency radar was deployed in mid-July to begin determining the velocity of surface currents. During the experiment, oceanographers cruised the Sound on transect lines to profile the temperature and salinity of the water column from top to bottom. They will deployrf a Slocum glider and other underwater vehicles (autonomous underwater vehicles or AUVs) that collected continuous measurements of temperature and salinity and deployed two sets of drifters in the central Sound beamed data about their speed and location to a satellite which was translated into current speed and direction. The data being collected was available for display in “real time” and in comparison to simulations being run on the models on the JPL’s “Sound Predictions 2009 Data Portal” website linked to www.aoos.org.
Return to News Archive