Four options on the Giovanni interface will be used to search SeaWiFS Level 1A and Level 2 data. The options are: Spatial Area Selection; Time Range Selection; Product Type; and Browse Image Type . Other options -- such as parameter, plot type, and color palette options -- are only used for generating image or ASCII output. More details about how to complete a data request from the search results page can be found on the Ocean Color Level 1 and 2 browser help page.
Spatial Area Selection:
Click and drag a box on the map to select a spatial area, or type in exact latitude and longitude values.
Time Range Selection:
Select Begin Year and Begin Month to set the starting date, and select End Year and End Month for the ending date. The dates within parentheses represent the maximum temporal range for the available data.
Product Type:
- GAC: Global-Area-Coverage data, recorded onboard the spacecraft and subsequently downloaded twice a day at NASA/Goddard. GAC data is subsampled along the center of the swath from full-resolution data by recording every fourth pixel of a scan line (from pixels 147 to 1135 of original 1285 pixels) and every fourth scan line. This provides an effective nadir spatial resolution of about 4.5 kilometers. Sample LAC image
- LAC: Local-Area-Coverage data, recorded at maximum 1.1 kilometer spatial resolution for selected parts of the world and downloaded with the GAC data. Sample LAC image
- MLAC: Merged Local-Area-Coverage data, which contains all available SeaWiFS HRPT (High Resolution Picture Transmission) station and LAC data for a given orbit. In regions with a high number of local HRPT stations, data collected from multiple stations will frequently overlap. Duplicate scans resulting from that overlap are evaluated through a series of quality tests, and only the "best quality" scan is stored in the MLAC file. Sample MLAC image
Browse Image Type:
- CHLO: the searched result page will display pseudocolor chlorophyll image.
- True Color: the search results page will display quasi true-color (3-band) images.
Restriction of SeaWiFS Data:
SeaWiFS data less than five years old can only be distributed to SeaWiFS Authorized Research Users. Although the entire SeaWiFS archive is viewable by anyone in the form of browse images, only authorized SeaWiFS users may obtain the higher-resolution Level 1 and Level 2 data files from which the browse images were generated. The SeaWiFS Authorized Research User username and password will be requested near the end of the data ordering procedure.
Click here to request a username and password if you have not registered for SeaWiFS data access with the Ocean Biology Processing Group.
