This project will continue to observe and understand the physics and biology of the highly productive northeast Pacific boundary current region over the continental slope off Washington and Oregon - the Cascadia slope - with an autonomous, sustained presence. For over a year, Seagliders, long-range autonomous underwater vehicles, have been deployed to survey the temperature, salinity, dissolved, oxygen, chlorophyll fluorescence, and optical backscatter structure of the slope off. Washington. Seagliders have collected data on sections from the continental shelf edge offshore 220 km at fortnightly intervals, reporting back data after each dive, on deployments typically lasting 4-5 months. The objective of the observations has been to detect seasonal and inter-annual variability in this part of the California Current system by collecting highly spatially and temporally resolved observations. Using Seagliders makes possible extended high resolution observations that would otherwise be prohibitively expensive if carried out by ships. This three-year project will: 1) analyze more than 16 months of Seaglider observations already collected, 2) continue the Seaglider observational program to over the continental shelf, and 3) analyze the newly collected data to describe the seasonal and interannual structure of the northern California Current system. Extension in time over the existing Seaglider repeat transects is necessary to confidently describe seasonal and interannual variability in the Cascadia slope region and to resolve and understand the (primarily advective) processes that are responsible for this variability. The data in hand offer tantalizing hints at the low frequency variability, but the 1.5 year record along two cross-slope sections is too limited to support quantitative understanding.
Broader Impacts: The results from this project will improve physical and biological understanding of climate change. By autonomously measuring important oceanographic parameters over a sustained period of time, it will be possible to establish an unprecedented climate record in an economically important area. By expanding the spatial coverage of the autonomous transects, we will be able to resolve and understand the contribution of advection. The results of this project will benefit resource planners by helping to understand the coastal zone ecosystem and influences of large scale ocean circulation on coastal and estuarine conditions in the Pacific Northwest. We will continue our outreach activities with presentations to local schools, open houses, public talks, and contacts with print and electronic media on local, national and international levels.
