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Dataset Title:  Lat-Lon Grid, Extended AVHRR Polar Pathfinder APP-X NCEI Climate Data Record
V2, Arctic
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Institution:  NOAA/NCEI   (Dataset ID: ncei_polarAPPX20_nhem_grid)
Information:  Summary ? | License ? | Metadata | Background (external link) | Files | Make a graph
 
Dimensions ? Start ? Stride ? Stop ?  Size ?    Spacing ?
 columns (m) ?      361    25067.53 (even)
  < slider >
 rows (m) ?      361    25067.53 (even)
  < slider >
 
Grid Variables (which always also download all of the dimension variables) 
 latitude (degrees_north) ?
 longitude (degrees_east) ?

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 {
  columns {
    String _CoordinateAxisType "GeoX";
    Float32 actual_range -4524688.0, 4499621.0;
    String axis "X";
    String comment "columns values are the upper left of the grid cells";
    String ioos_category "Location";
    String long_name "Projection Grid X Coordinates";
    String standard_name "projection_x_coordinate";
    String units "m";
  }
  rows {
    String _CoordinateAxisType "GeoY";
    Float32 actual_range -4499620.0, 4524689.0;
    String axis "Y";
    String comment "columns values are the upper left of the grid cells";
    String ioos_category "Location";
    String long_name "Projection Grid Y Coordinates";
    String standard_name "projection_y_coordinate";
    String units "m";
  }
  latitude {
    Float64 colorBarMaximum 90.0;
    Float64 colorBarMinimum 0.0;
    String comment "These are latitude coordinate values which correspond to rows (y axis) projected coordinate dimension values";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
  }
  longitude {
    Float64 colorBarMaximum 180.0;
    Float64 colorBarMinimum -180.0;
    String comment "These are longitude coordinate values which correspond to columns (x axis) projected coordinate dimension values";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
  }
  NC_GLOBAL {
    String _NCProperties "version=1|netcdflibversion=4.4.1.1|hdf5libversion=1.8.17";
    String acknowledgement "Please acknowledge NCEI, CoastWatch West Coast Node, and this dataset (doi:10.25921/AE96-0E57).";
    String cdm_data_type "Grid";
    String cdr_program "NOAA Climate Data Record Program for satellites";
    String cdr_variable "cdr_surface_temperature, cdr_surface_albedo, cdr_surface_downwelling_shortwave_flux, cdr_surface_downwelling_longwave_flux, cdr_surface_upwelling_shortwave_flux, cdr_surface_upwelling_longwave_flux, cdr_cloud_binary_mask, cdr_sea_ice_thickness, cdr_toa_net_downward_shortwave_flux, cdr_toa_outgoing_shortwave_flux, cdr_toa_outgoing_longwave_flux,surface_type, cloud_particle_phase, cloud_particle_radius, cloud_optical_depth, cloud_top_pressure, cloud_top_temperature, Cloud_type, surface_shortwave_cloud_radiative_forcing, surface_longwave_cloud_radiative_forcing";
    String comment "In order to be compliant with the EASE Grid specifications, the following modifications were made to the source files: 1) For each data variable plus the latitude and longitude variables, the two dimensional x-y grid was rotated clockwise by 90 degrees, resulting in geographical orientation where the Greenwich Meridian runs parallel to the y (rows)-axis from the North Pole at the grid center to the middle of the x (columns)-axis at the bottom edge of the grid and -90 degree E meridian runs parallel to the x (columns)-axis from the North Pole at the grid center to the middle of the y (rows)-axis at the left edge of the grid.: 2) two coordinate variables (columns and rows) were added that correspond to the columns and rows dimensions (units of m). In addition, the time variable was modified to put all of the files in the dataset on the same base time (seconds since 1970-01-01T00:00:00Z).";
    String Conventions "COARDS, CF-1.4, Unidata Dataset Discovery v1.0";
    String creator_email "erd.data@noaa.gov";
    String creator_name "NOAA/NMFS/SWFSC/ERD and NOAA/NESDIS/CoastWatch West Coast Node";
    String creator_type "institution";
    String date_created "2019-06-25";
    String defaultGraphQuery "cdr_sea_ice_thickness[(last)][(-4499620.5):(4524688.5)][(-4524688.5):(4499620.5)]&.draw=surface";
    String doi "doi.org/10.25921/AE96-0E57";
    String EPSG "http://epsg.io/3408";
    String history 
"Data files were obtained from NCEI at https://www.ncei.noaa.gov/data/avhrr-polar-pathfinder-extended/access/. For each data variable plus the latitude and longitude variables, the two dimensional x-y grid was rotated clockwise by 90 degrees, resulting in geographical orientation where the Greenwich Meridian runs parallel to the y (rows)-axis from the North Pole at the grid center to the middle of the x (columns)-axis at the bottom edge of the grid and -90 degree E meridian runs parallel to the x (columns)-axis from the North Pole at the grid center to the middle of the y (rows)-axis at the left edge of the grid. To coordinate variables (columns and rows) were added that correspond to the columns and rows dimensions. The coordinate variables have units of meters. The timestamp was made consistent across all files by converting to seconds since 1970-01-01T00:00:00Z. Metadata were alter to be in compliance with CF and ACDD standards.
2024-03-29T01:21:12Z https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/gov.noaa.ncdc:C00941/html
2024-03-29T01:21:12Z https://polarwatch.noaa.gov/erddap/griddap/ncei_polarAPPX20_nhem_grid.das";
    String id "Polar-APP-X_v02r00_Nhem";
    String infoUrl "\"https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/gov.noaa.ncdc:C00941/html\"";
    String institution "NOAA/NCEI";
    String keywords "Earth Science > Atmosphere > Atmospheric Radiation > Longwave Radiation, Earth Science > Atmosphere > Atmospheric Radiation > Radiative Flux, Earth Science > Atmosphere > Atmospheric Radiation > Solar Radiation, Earth Science > Atmosphere > Clouds > Cloud Microphysics > Cloud Droplet Concentration(Size), Earth Science > Atmosphere > Clouds > Cloud Microphysics > Cloud Droplet Phase, Earth Science > Atmosphere > Clouds > Cloud Microphysics > Cloud Optical Depth(Thickness), Earth Science > Atmosphere > Clouds > Cloud Properties > Cloud Fraction, Earth Science > Atmosphere > Clouds > Cloud Properties > Cloud Top Pressure, Earth Science > Atmosphere > Clouds > Cloud Properties > Cloud Top Temperature, Earth Science > Atmosphere > Clouds > Cloud Properties > Cloud Type, Earth Science > Atmosphere > Clouds > Cloud Radiative Transfer > Cloud Radiative Forcing, Earth Science > Climate Indicators > Cryospheric Indicators > Ice Depth(Thickness), Earth Science > Cryosphere > Sea Ice > Ice Depth(Thickness), Earth Science > Cryosphere > Snow And Ice > Albedo, Earth Science > Cryosphere > Snow And Ice > Snow And Ice Temperature, Earth Science > Land Surface > Land Albedo, Earth Science > Land Surface > Land Temperature, Earth Science > Oceans > Sea Ice > Ice Depth(Thickness), Earth Science > Terrestrial Hydrosphere > Snow And Ice > Albedo, Earth Science > Terrestrial Hydrosphere > Snow And Ice > Ice Depth(Thickness)";
    String keywords_vocabulary "NASA Global Change Master Directory (GCMD) Earth Science Keywords, Version 8";
    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.";
    String Metadata_Conventions "COARDS, CF-1.6, Unidata Dataset Discovery v1.0";
    String metadata_link "https://doi.org/10.25921/AE96-0E57";
    String naming_authority "gov.noaa.ncei";
    String NCO "\"4.6.3\"";
    Int32 nco_openmp_thread_number 1;
    String platform " NOAA polar orbiting satellite 19";
    String product_version "V2.0";
    String PROJ4 "+proj=laea +lat_0=90 +lon_0=0 +x_0=0 +y_0=0 +a=6371228 +b=6371228 +units=m +no_defs";
    String publisher_email "erd.data@noaa.gov";
    String publisher_name "NOAA/NMFS/SWFSC/ERD and NOAA/NESDIS/CoastWatch West Coast Node";
    String publisher_type "institution";
    String references "doi.org/10.25921/AE96-0E57";
    String sensor "Advanced Very High Resolution Radiometer (AVHRR)/3";
    String source "individual twice daily APP-x data";
    String sourceUrl "https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/gov.noaa.ncdc:C00941/html";
    String spatial_resolution "25 km";
    String standard_name_vocabulary "CF Standard Name Table (v26, 08 November 2013)";
    String summary "summary";
    String title "Lat-Lon Grid, Extended AVHRR Polar Pathfinder APP-X NCEI Climate Data Record V2, Arctic";
  }
}

 

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
https://coastwatch.pfeg.noaa.gov/erddap/griddap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/griddap/jplMURSST41.htmlTable?analysed_sst[(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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