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Dataset Title:  OSU Chlorophyll Anomaly V2, MODIS Aqua, West US, 2003-present Subscribe RSS
Institution:  Oregon State University   (Dataset ID: osu2ChlaAnom)
Information:  Summary ? | License ? | FGDC | ISO 19115 | Metadata | Background (external link) | Make a graph
Dimensions ? Start ? Stride ? Stop ?  Size ?    Spacing ?
 time (UTC) ?      210    33 days 18h 43m 4s (uneven)
  < slider >
 altitude (m) ?      1    (just one value)
  < slider >
 latitude (degrees_north) ?      2321    0.0125 (even)
  < slider >
 longitude (degrees_east) ?      2401    0.0125 (even)
  < slider >
Grid Variables (which always also download all of the dimension variables) 
 chla_anomaly (Chlorophyll Anomaly, mg m-3) ?

File type: (more information)

(Documentation / Bypass this form) ?
(Please be patient. It may take a while to get the data.)


The Dataset Attribute Structure (.das) for this Dataset

Attributes {
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.0426752e+9, 1.6526592e+9;
    String axis "T";
    String ioos_category "Time";
    String long_name "Time";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  altitude {
    String _CoordinateAxisType "Height";
    String _CoordinateZisPositive "up";
    Float64 actual_range 0.0, 0.0;
    String axis "Z";
    Int32 fraction_digits 0;
    String ioos_category "Location";
    String long_name "Altitude";
    String positive "up";
    String standard_name "altitude";
    String units "m";
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 actual_range 22.0, 51.0;
    String axis "Y";
    String coordsys "geographic";
    Int32 fraction_digits 4;
    String ioos_category "Location";
    String long_name "Latitude";
    String point_spacing "even";
    String standard_name "latitude";
    String units "degrees_north";
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range 225.0, 255.0;
    String axis "X";
    String coordsys "geographic";
    Int32 fraction_digits 4;
    String ioos_category "Location";
    String long_name "Longitude";
    String point_spacing "even";
    String standard_name "longitude";
    String units "degrees_east";
  chla_anomaly {
    Float32 _FillValue 1.0e+30;
    String _standard_name "concentration_of_chlorophyll_in_sea_water_anomaly";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum -10.0;
    String ioos_category "Ocean Color";
    String long_name "Chlorophyll Anomaly";
    String units "mg m-3";
    String cdm_data_type "Grid";
    String contact "Craig Risien (";
    String Conventions "CF-1.6, COARDS, ACDD-1.3";
    String creator_email "";
    String creator_name "Craig Risien";
    String creator_type "person";
    Float64 Easternmost_Easting 255.0;
    Float64 geospatial_lat_max 51.0;
    Float64 geospatial_lat_min 22.0;
    Float64 geospatial_lat_resolution 0.0125;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 255.0;
    Float64 geospatial_lon_min 225.0;
    Float64 geospatial_lon_resolution 0.0125;
    String geospatial_lon_units "degrees_east";
    Float64 geospatial_vertical_max 0.0;
    Float64 geospatial_vertical_min 0.0;
    String geospatial_vertical_positive "up";
    String geospatial_vertical_units "m";
    String history 
    String infoUrl "";
    String institution "Oregon State University";
    String keywords "anomaly, aqua, atmospheric, chemistry, chlorophyll, coast, college, color, earth, Earth Science > Oceans > Ocean Chemistry > Chlorophyll, fields, high, modis, ocean, oceancolor, oceans, oregon, resolution, sciences, state, u.s., university, west, west coast";
    String license 
"The data may be used and redistributed for free but is not intended
for legal use, since it may contain inaccuracies. Neither the data
Contributor, ERD, NOAA, nor the United States Government, nor any
of their employees or contractors, makes any warranty, express or
implied, including warranties of merchantability and fitness for a
particular purpose, or assumes any legal liability for the accuracy,
completeness, or usefulness, of this information.";
    Float64 Northernmost_Northing 51.0;
    String product_version "1.0";
    String references "Risien, C.M., and P.T. Strub. Satellite-Derived Climatologies: The California Current Large Marine Ecosystem. Cooperative Institute for Oceanographic Satellite Studies. Available online at";
    String sourceUrl "";
    Float64 Southernmost_Northing 22.0;
    String spatial_resolution "0.025 degree";
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "This suite of CHLA and SST climatology and anomaly data products are derived from daily, 0.0125 degree x 0.0125 degree, MODIS Aqua CHLA and SST fields that cover the California Current System (22N - 51N, 155W - 105W) for the 11-year period July 2002 through June 2013. These daily fields, obtained from the NOAA CoastWatch West Coast Regional Node website, were processed using a successive 3x3, 5x5 and 7x7 grid cell hybrid median filtering technique. This technique was found to effectively reduce noise in the daily fields while maintaining features and detail in important regions such as capes and headlands. The resulting median filtered daily fields were then linearly interpolated to a 0.025 x 0.025 degree grid and averaged to create 132 monthly mean fields. The seasonal cycles at each 0.025 degree x 0.025 degree grid cell were obtained by fitting each multiyear time series of monthly means to a nine-parameter regression model consisting of a constant plus four harmonics (frequencies of N/(1-year), N-1,4; Risien and Chelton 2008, JPO).  Even with the median filtering and the temporal averaging of the daily fields, the highly inhomogeneous nature of the MODIS fields still resulted in regression coefficients that were excessively noisy. We therefore applied the same successive 3x3, 5x5 and 7x7 hybrid median filtering technique, described above, to the regression coefficients before finally spatially smoothing the coefficients using a loess smoother (Schlax et al. 2001, JTECH) with filter cutoff wavelengths of 0.25 degree latitude by 0.25 degree longitude. The seasonal cycles were then calculated from the filtered regression coefficients for each 0.025 degree x 0.025 degree grid cell using the mean and all four harmonics. It is important to note that THIS SUITE OF DATA PRODUCTS IS HIGHLY EXPERIMENTAL and is strictly intended for scientific evaluation by experienced marine scientists.";
    String time_coverage_end "2022-05-16T00:00:00Z";
    String time_coverage_start "2003-01-16T00:00:00Z";
    String title "OSU Chlorophyll Anomaly V2, MODIS Aqua, West US, 2003-present";
    Float64 Westernmost_Easting 225.0;


Using griddap to Request Data and Graphs from Gridded Datasets

griddap lets you request a data subset, graph, or map from a gridded dataset (for example, sea surface temperature data from a satellite), via a specially formed URL. griddap uses the OPeNDAP (external link) Data Access Protocol (DAP) (external link) and its projection constraints (external link).

The URL specifies what you want: the dataset, a description of the graph or the subset of the data, and the file type for the response.

griddap request URLs must be in the form{?query}
For example,[(2002-06-01T09:00:00Z)][(-89.99):1000:(89.99)][(-179.99):1000:(180.0)]
Thus, the query is often a data variable name (e.g., analysed_sst), followed by [(start):stride:(stop)] (or a shorter variation of that) for each of the variable's dimensions (for example, [time][latitude][longitude]).

For details, see the griddap Documentation.

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