A synthesis of climate-forced variability on mesoscale structure in the Coastal Gulf of Alaska with direct comparisons to the California Current System

A variety of extreme climate events occurred during the period of US GLOBEC monitoring and process studies in the NorthEast Pacific (1997-2004). These provide an unprecedented opportunity to examine a range of climate variability experienced by the coastal Gulf of Alaska (CGOA). By relating these climate events to regional physical and biological observations, using multiple and diverse data sources (GLOBEC observations, historical data sets and reanalyses, satellites, models), we can determine how these events affect mesoscale ocean variability in the CGOA and its related target populations (the primary goal of the NEP program). We can then directly compare these responses to those evident in the California Current System (CCS).

We have two overarching goals in this project. 1) Characterize the linkages between basin-scale variability indicative of climate events and local CGOA changes in mesoscale variability that impact ecosystem pattern, structure and productivity. 2) Compare the linkages between basin-scale and local structure in the coastal Gulf of Alaska (CGOA) with those evident in the CCS, contrasting differing ecosystem responses to the same climate signals.

Our emphasis is on synthesis of physical circulation, upper ocean structure, nutrients and lower (planktonic) trophic levels to develop metrics based on multiple data sets spanning a wide spectrum of space and time scales. A funded GLOBEC-NEP Phase IIIa proposal to the same PIs to carry out similar analyses in the CCS provides significant leverage, both financially and intellectually. Our team of investigators represents expertise in diverse aspects of climate mesoscale interactions and data analysis. We initially use correlative methods to characterize mesoscale variability in the CGOA and the concurrent basin-scale conditions during Field Program years, and then extend these comparisons back in time where possible. We will build on these correlational linkages between basin-scale and mesoscale patterns, examining the mechanisms behind these linkages from three points of view: i) comparing interannual and decadal scales of climate variability, ii) identifying and comparing different shelf regions of climate response in the CGOA, and iii) examining changes in seasonal signals. We then compare and contrast signals observed in the CCS to those in the CGOA.

This project will contribute to the analyses (papers), data sets, and indices for monitoring, assessing, and managing marine resources in the CGOA. By integrating and analyzing multiple data sets, we will provide robust indicators of the response of the CGOA shelf to climate change, a useful tool for resource assessment and management. Improvement of ecosystem management strategies for the Alaskan shelf directly affects a large socio-economic sector of the US west coast. Our comparison of CCS and CGOA provides a Pacific basin-wide synthesis of shelf ecosystem response to climate forcing. The datasets, satellite images and key metrics and indices developed here will be served on a series of Live Access Servers (LAS) and OPeNDAP Servers used for our CCS project, allowing scientists, resource managers, and the public to transparently access, subset and download our data products.