Exploring Oceanographic Data in the Classroom Using the Laboratory for Ocean Color Users

Data from NASA's Laboratory for Ocean Color Users is intended to provide a guided pathway to aid in the utilization of ocean color data for oceanographic and environmental research. Ocean color data provides an expression of biological activity in the oceans. Other related data parameters such as sea surface temperature are also available. LOCUS presents data using the web-based Giovanni analysis and visualization system, which enables rapid and basic statistical analyses, data sub-setting, and graphics output. The Ocean Color Web (Web site of the Ocean Biology Processing Group) provides more information and access to the complete suite of NASA ocean color data products.

Scientists use ocean color data to examine biological activity in the oceans, and physical and biological interactions. LOCUS data can also be used to examine current forcing and changes in ocean current systems. The LOCUS data set examines oceanographic processes at the surface and links biological activity, such as phytoplankton blooms, with physical properties of the ocean surface including SST and circulation patterns. Data analyses using LOCUS and Giovanni allow scientists to examine diverse research problems including:

• "Influence of El Niño on the Gulf of Panama Seasonal Productivity Cycle"
• "Can seasonal patterns of phytoplankton productivity be observed in the Red Sea?"
• "How can scatter plots be used to determine what relationships may exist between chlorophyll and sea surface temperature (SST) in the Gulf of Mexico?" From LOCUShomepage.

This data can be used to teach the following concepts and skills in physical and biological oceanography:

• Estuarine dynamics
• Ocean current systems
• Upwelling
• El Niño and La Niña variability
• Climate change

• Interpreting remote sensing data to examine relationships between upwelling and primary productivity
• Understanding sea surface temperature and current oscillations
• Exploring the effects of estuaries on coastal regions
• Using the tool Giovanni to examine ocean color data
• Examining temporal and spatial changes in primary productivity through analysis of changes in chlorophyll concentration
• Generating plots to analyze potential impacts of physical oceanographic properties, such as SST and current upwelling, on primary productivity

Processed data for ocean color including SST, chlorophyll, and quasi-true color images is archived and can be accessed through LOCUS data products for a period ranging from 1978 to present. SST images are false-colored to represent temperature ranges from -2°C (purple) to 34°C (red). Chlorophyll images are false-colored to represent concentrations from .01 mg/m³ (purple) to 60 mg/m³ (red). Images are available for the SeaWiFS color bars representing SST and chlorophyll concentration.

SST, chlorophyll data, and quasi-true images can be obtained directly from the LOCUS website. Users can choose which subsets of data to examine. The Level 1A and 2 Browser allows users to parse data based on geographic location and data origin from satellites, including MODIS and SeaWiFS.

Ocean color data can also be visualized using the online tool Giovanni (GES-DISC Interactive On-line Visualization and ANalysis Infrastructure). Users can browse SeaWiFS and MODIS satellite data through a JAVA interface and generate GIF images or ASCII output files providing SST and chlorophyll data from September 1997 to present. Data can be accessed as time-averaged, area averaged, as an animation spanning a selected time period, or as Hovmoller plots (which plot either latitude or longitude versus time).

Giovanni can be used to generate images and animations showing SeaWiFS ocean color data and MODIS ocean color and SST data. The LOCUS homepage contains six educational modules and six tutorials that describe step by step use of Giovanni. A guide to using Giovanni is also available in a PowerPoint presentation, Giovanni and LOCUS: Innovative Ways for Teachers and Students to Conduct Online Learning and Research with Oceanographic Remote Sensing Data, presented by James Acker at a meeting of the National Marine Educator's Association.

Remote sensing via satellites is used to collect data on chlorophyll concentrations in the oceans and SST. Informational links are provided explaining how data from MODIS-Aqua and SeaWiFS are processed using algorithms to determine SST data and chlorophyll concentration. Detailed information on the MODIS and SeaWiFS satellites is available from NASA and through the Scientific Documentation section of LOCUS.

Several factors including sensing in coastal regions, aerosols in the atmosphere, and phytoplankton blooms can introduce sources of error in how remote sensing data is interpreted.

• Remotely-sensed chl a at the Chesapeake Bay mouth is correlated with annual freshwater flow to Chesapeake Bay: An article from Geophysical Research Letters that discusses use of SeaWiFS data and the Giovanni processing tool to examine the relationship between biogeochemical cyles and primary productivity (Acker et al., 2005).
• Satellite Sees Chlorophyll Stirred up by Hurricane Katrina: This NASA "Looking at Earth" featured article examines the use of SeaWiFS data and the Giovanni tool for examining changes in phytoplankton dynamics during Hurricane Katrina.
• Drought and Deluge Change Chesapeake Bay Biology: This Features article from the Earth Observatory discusses how remote sensing of ocean color was used to examine ecosystem changes in the Chesapeake Bay.

• The LOCUS homepage has six education modules and six tutorials that can be used as guided activities for use in teaching.
• LOCUS Modules and tutorials span divers topics including:
  • The Southern Oceans
  • Major Boundary Currents
  • Different Kinds of Chlorophyll Concentration Anomalies in the North Atlantic Bloom
  • Seasonal Patterns and Mysteries in the Red Sea
• A Teacher's Collection is available that provides links with information on SeaWiFS data collection and interpretation.
• A series of activities are available from the SeaWiFS project that use ocean color data to study phytoplankton, the carbon cycle, and how the ocean is viewed from space

• Estimation of phytoplankton production from space: current status and future potential of satellite remote sensing.: This article from the Journal of experimental marine biology and ecology reviews the use of SeaWiFS data and potential sources of error in remote sensing (Joint and Groom, 2000).
• An evaluation of MODIS and SeaWiFS bio-optical algorithms in the Baltic Sea: This article from Remote Sensing of Environment addresses the computational analyses used to process MODIS and SeaWiFS data.

• The Teacher's Resource Collection from the University of South Florida's Ocean Remote Sensing Base for Interactive Teaching and Learning (ORBITAL) provides a number of activities related to remote sensing and ocean color.

• The Teaching with Data portal of SERC contains information on teaching with graphs, including a section on Hovmoller plots.
• When is Dinner Served? Predicting the Spring Phytoplankton Bloom in the Gulf of Maine is an Earth Exploration Toolbook chapter that uses data, including MODIS data, to predict phytoplankton blooms.