GLOBEC NEP: Satellite-Observed Ocean Climate Variability
P.T. Strub, M.R. Abbott [Oregon State University], J. Svejkovsky [Ocean Imaging, Inc], A.C. Thomas [University of Maine]
We propose to extend in time and expand in scope the satellite data development and satellite-based analyses of ocean climate variability in the Northeast Pacific (NEP), begun during the GLOBEC Pilot Project phase (1997-00). The overall scientific problem is to characterize and quantify the dominant modes of variability in the NEP as embodied by satellite measurements of surface transports, temperature and chlorophyll patterns. Our analyses address multiple spatial and temporal scales using merged satellite data products over GLOBEC target study regions in both the California Current (CCS) and the coastal Gulf of Alaska (CGOA).
GLOBEC NEP field studies require both spatial and temporal context. Our primary goal is to quantify the degree of seasonal and interannual variability in small scale and mesoscale circulation patterns in each of the process study sites, and to relate changes in this variability to the seasonal and interannual changes in the strength of forcing by local winds and basin scale circulation. We approach this goal through a systematic analysis of spatial / temporal scales utilizing satellite measurements. We will define and quantify a) small event-scale coastal features such as fronts, eddies and convergences (order 50m to 100km). These are thought to be critical to local success / survival of GLOBEC target species, b) mesoscale circulation / seasonal variability over the shelf, upwelling fronts, coastal jets, buoyant plumes and eddies (order 10km to 500km). These also affect transport and retention of populations; and c) forcing and processes at basin and interannual scales (order 100km to 10,000km). A second, related goal is to quantify changes in the timing and strength of seasonal transitions in both study regions. Temporal variability is an integral component of biological / physical interaction. We begin the analysis of seasonal transitions using an analysis of the spring transition at the coast (tide gauge sea levels) in the California Current. We will expand this in the CCS to include satellite estimates of SST, transports and pigments in the several hundred kilometers next to the coast. We will then use the same tools to look at the nature of seasonal transitions in the CGOA. A third goal is to determine changes in the upwelling strength, cross-margin transport and potential entrainment of biological populations into the seasonal offshore jet, as characterized by high resolution satellite measurements of evolving fronts, jets and the width of the upwelling zone.
Specific objectives of the proposed work are divided into two aspects of satellite oceanography:
Our proposed work plan is to finish, during the first year, analyses of basin scale / interannual variability, fortuitously imposed by the large 1997-98 ENSO signal during the Pilot Project in the study region. We will also begin to shift emphasis to analyses of mesoscale and small scale variability to coincide with GLOBEC process studies and other (e.g. LTOP) field work. This will continue during the field work. In the last, synthesis, phase of the project, when our longest time series of satellite (and other) data are available, we will return to the larger scale analysis to quantify linkages between the mesoscale and small scale variability and basin scale and interannual variability. An important objective of this proposal, made in parallel to the satellite data analysis, is the delivery of processed satellite data fields via a WWW site to the GLOBEC community for field work support, planning and analyses.
Ocean Imaging (OI, J. Svejkovsky):
This page was last updated on
March 15, 2007.
Maintained by:
Hal Batchelder
College of Oceanic and Atmospheric Sciences
Oregon State University
Corvallis, OR 97331-5503
phone: 541-737-4500; FAX 541-737-2064