Satellite Applications for LMRs

The Environmental Research Division has taken a lead role in both representing NOAA Fisheries needs and requirements for satellite data and in using satellite data to better understand the impacts of environmental variability on marine ecosystems and fisheries.  The continuity, global coverage, and high temporal and spatial resolution of satellite data make it an important tool for monitoring and characterizing marine ecosystems. Although satellites do not observe fish stocks directly, measurements such as sea-surface temperature (SST), sea-surface height (SSH), ocean color, ocean winds and sea ice, characterize critical habitat that influences marine resources. Most of the spatial features that are important to ecosystems, i.e. ocean fronts, eddies, convergence zones, river plumes and coastal regions, cannot be adequately resolved without satellite data. Chlorophyll is the only biological component of the marine ecosystem accessible to remote sensing (via ocean color), and as such provides a key metric for assessing the health and productivity of marine ecosystems on a global scale. Specific applications of satellite data include:

Additional applications of satellite data to LMRs can be seen in the bibliography of published papers (not limited to SWFSC or ERD publications).

Improving Access to, and Usage of, Satellite Data with NMFS

The Environmental Research Division has taken a lead role in representing NOAA Fisheries needs and requirements for satellite data.   Currently many personnel within NMFS are not aware of the wealth of satellite data that exists, or lack the knowledge and skills to efficiently access and use this data.  Efforts at ERD have focused on addressing this issue through a number of recent activities, most of which have been funded or supported  by NOAA’s satellite Research & Operations (R&O) project:


Satellite Studies at ERD

30°N Chlorophyll Blooms


Figure 1. Satellite chlorophyll image from SeaWiFS showing large bloom in Oct. 2000.

Work on ERD has focused on the potential causes and effects of chlorophyll blooms in the N. Pacific that were first discovered with satellite data (Wilson, GRL, 2003). Nitrogen fixation and the vertical migration of Rhizosolenia diatom mats below the nutricline are possible mechanisms for the supply of new nitrogen to fuel the chlorophyll blooms, but there has not been any systematic sampling of these blooms to allow characterizing them with any certainty (Wilson et al., JMS, 2006). The blooms occur in se blooms could have important ecosystem consequences by impacting local carbon fluxes and serving as an aggregation point for pelagic animals.  Work is also underway investigating the global occurrence of similar blooms.


Tagging of Pacific Pelagics (TOPPThe previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer)

Researchers at ERD are collaborating with the Tagging of Pacific Pelagics (TOPP) program to understand the environmental basis for movements and behaviors of large pelagic animals in the North Pacific.  Over 20 species, and 200,000 individual animals have been equipped with tags that track the location, and environmental parameters experiences by the animal.  A Live Action Server (LAS) developed at ERD provides researchers a mechanism to easily merge the near real time data from animal tags with environmental data from satellites and other sources. 


Elephant seal track from the TOPP Program overlaid on top of MODIS chlorophyll.


Eddy Census in the Eastern Tropical Pacific

Researchers at ERD have used timeseries of satellite altimetry to characterize the nature and intensity of anticyclonic eddies in the eastern tropical Pacific Ocean. Interannual variability in the number, size, and intensity of eddies is evident from maps of SLA at the times of peak eddy activity for each eddy season, shown in the adjacent figure.  There is significant interannual variability in the number and characteristics of eddies, and in the timing and duration of the eddy season, associated with the El Nino-La Nina cycle. These eddies are important to the regional ecosystem as they transport nutrient-rich coastal waters and organisms to the ocean interior, and their annual recurrence, intensity, and persistence suggests that they may be important biological hot spots.

Maps of satellite sea-surface

Maps of satellite sea-surface height for the 7-day period of peak eddy activity during each eddy season, over the period 14 October 1992 to 18 August 2004.  From Palacios and Bograd, GRL, 2005.


Integrating Satellite Data into Coastal Management

Researchers at ERD have collaborated with personnel from NOAA’s Monterery Bay Sanctuary to use satellite SST data to characterize the oceanic features in the vicinity of the Cordell Bank National Marine Sanctuary, the Gulf of Farallones National Marine Sanctuary and the Monterey Bay National Marine Sanctuary.  There are strong variations is the distribution of upwelling regions, offshore intrusions of warm water and frontal zones, all of which impact the regional ecosystem.  Consequentially, using satellite data to better document the geographic extent of these phenomena can be useful in determining the boundaries of marine reserves designed to protect marine LMRs.

Maps showing the seasonal distribution of upwelling regions (blue), warm offshore intrusions (red) and frontal zones (green) as derived from satellite SST data.  The dashed line marks the boundaries of the Cordell Bank, Gulf of Farallones and Monterey Bay National Marine Sanctuaries. From Stegmann et al., EOS, 2006


Sea Ice Data and Minke Whale Population Estimates

A collaboration between ERD and MMTD is using satellite sea ice records to better understand the abundances of Antarctica Minke whales.  The last estimate of their populations, 338,000 in circumpolar survey III (CP-III) was less than half the size of the previous estimate, 786,000 in CP-II. One of the primary hypothesis to account for this large discrepancy is that changes in sea ice extent affecting the accuracy of the counts.  For example, greater ice extent provides more habitat for whales to hide in, and would lower the population estimate.  This trend is in fact seen in the data as shown below.  However the issue is not straightforward, for example large polynyas can occur within the pack ice, and when not surveyed, as occurred between CP-II and CP-III, could result in a smaller population estimate.


Sea ice extent in the Weddell Sea during (left) CP-II and (right) CP-III. The large polynya during CP-II could have harbored whales not counted by the survey and accounted for the >100,000 population decrease estimated for this region between the surveys.

Relationship between estimated whale population and the area of sea ice extent for each of the six Antarctic sections.  Greater ice extent is associated with lower populations estimates. 


Interannual Variability in the Transitional Zone Chlorophyll Front (TZCF)

The Transitional Zone Chlorophyll Front (TZCF) is prominent feature in the North Pacific that separates high chlorophyll subpolar waters from the low chlorophyll, less productive waters.  The TZCF is an important migratory and foraging ground for loggerhead turtles and number of commercial fish species.   Work at ERD has shown anomalous displacement in the wintertime extent of the TZCF during significant El Nino and La Nina years, as well as changes on decadal timescales.  Interannual variability in the position and strength of the TZCF could have important implications for the distribution and survival of the numerous species that utilize the TZCF.

(a) Average surface chlorophyll in the N. Pacific between Sept 1997-Oct. 2003.  The mean position of the TZCF is in black, and the summer and winter positions indicated in white. (b) Monthly mean and standard deviations of the TZCF latitude, showing the winter anomalies associated the 1998 and 1999 El Nino and La Nina years. From Bograd et al., GRL, 2004.


Related ERD Programs


Key Links


Relevance to NOAA ‘s Strategic Mission for Fiscal Years 2008-2012