Regional Oceanography of the Northeast Pacific


The Environmental Research Division has a strong tradition of research in ocean dynamics, climate variability, and fisheries oceanography. Although global in scope, a research emphasis is placed on the Northeast Pacific Ocean (NEP), and on the California Current System (CCS) in particular. Recent research efforts have focused on the following topics:

  • Studies of environmental variability and ecosystem response within the California Current System and other eastern boundary current systems, on time scales from weeks to decades;
  • Studies of large-scale climate variability of the North Pacific, with emphasis on the nature, causes, and biological impacts of regime shifts ( Climate Change and LMEs );
  • Studies integrating satellite oceanography with studies of ocean dynamics and fisheries oceanography (Satellite Applications for LMRs);
  • Studies of marine habitat utilization by apex marine predators throughout the North Pacific through directed tagging efforts, as part of Census of Marine Life’s Tagging of Pacific Pelagics (TOPP The previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer ) program.


The principal objectives of this research are to:

  • Specify linkages of environmental processes to population dynamics of key fish stocks;
  • Develop the means to effectively forecast the effects of environmental variations on fish availability and the resilience of fish populations to exploitation;
  • Assess the effects of climate change on oceanographic processes critical to fish populations;
  • Use new approaches and technologies to characterize and evaluate marine fisheries habitat, and the impacts of habitat change on marine populations;
  • Develop climate indices that reflect the important mechanisms of physical-biological coupling over a range of space-time scales.


A number of research methods are used to examine environmental variability in the CCS:

  • Traditional analyses of water properties and circulation from hydrographic data;
  • Novel statistical techniques, including state-space modeling, to decompose environmental time series and distinguish the mechanisms and timing of climate shifts;
  • Combined use of satellite-derived and in situ data sets for improved understanding of water column structure and biological productivity;
  • Targeted tagging studies of large pelagics and marine mammals.

Recent Results

Seasonality of Physical-Biological Coupling in the CCS

Motivation:  Life cycles of many marine organisms are closely tied to seasonal processes.


  • Improve understanding of the seasonal evolution of the CCS;
  • Examine variability in the timing of the spring transition;
  • Quantify long-term changes in the seasonal amplitude and timing of relevant physical processes, such as coastal upwelling.
Maps of (a,b) surface temperature and (c,d) fluorescence

Maps of (a,b) surface temperature and (c,d) fluorescence off the California coast just prior to (March) and after (April) the 1995 spring transition. Large changes in physical structure and biological response are evident over the course of a few weeks. From Lynn et al. (2003).

Interannual Variability in the CCS

Motivation: Living marine resources are greatly impacted by interannual variability in environmental conditions and processes.


  • Identify the sources and mechanisms of interannual variability in the CCS;
  • Quantify long-term trends in relevant physical and biological variables;
  • Classify El Nino events by their varying physical-biological impact in the CCS;
  •  Develop leading physical and biological indicators of ecosystem change.
Hovmoller diagrams

Hovmoller diagrams of nitracline depth (top), vertically-integrated chlorophyll-a (middle), and macrozooplankton biomass (bottom) for CalCOFI Lines 80 (left) and 90 (right), for the period January 1996 – October 1999. This was a period of transition from a strong El Nino event in 1997-98 (deep nitracline, low chlorophyll and zooplankton) to a strong La Nina event in 1998-99 (shallow nitracline and enhanced productivity). From Bograd and Lynn (2001).


Time series sections of temperature

Time series sections of temperature and vertical temperature gradient for an offshore (left) and coastal (right) location in the central CCS. Bottom time series show varying long-term trends in the strength of stratification (increasing at coast) and depth of the thermocline (increasing at coast) over the period 1950-93. From Palacios et al. (2004).


North Pacific Climate Change and Ecosystem Response

Motivation: Major ecosystem fluctuations are associated with decadal-scale shifts in environmental conditions and forcing.


  • Identify and quantify leading physical-biological indicators of climate change in the North Pacific;
  • Apply novel time series methods for the detection of regime shifts;
  • Develop an operational definition of a regime shift for application to management strategy.
Winter maps of SST

Winter maps of SST anomalies (top) and SLP + vector wind anomalies (bottom) averaged over three periods: 1970-76, 1977-83, and 1999-2002. There appears to have been a transition to a new climate regime following the 1997-98 El Ni?o event. From Peterson and Schwing (2003).

Taken together, these results demonstrate the importance of evaluating temporal and spatial variability over the entire spectrum, and of independently considering changes in seasonal patterns and long-term trends. Evidence suggests that the ecosystem can respond in less than one growing season to a new regime and may return rapidly to a former state associated with a previous regime. Our research indicates that we may be able to characterize ocean regimes in terms of their carrying capacity or suitability for specific stocks.

Last modified: 12/24/2014