ERDDAP > info > SNAP_SEA_ICE_ATLAS

Grid DAP Data	Sub- set	Table DAP Data	Make A Graph	W M S	Source Data Files	Title	Sum- mary	FGDC, ISO, Metadata	Back- ground Info	RSS	E mail	Institution	Dataset ID
data			graph	M		Data from a local source.		F   I   M	background			???	SNAP_SEA_ICE_ATLAS

The Dataset's Variables and Attributes

Row Type	Variable Name	Attribute Name	Data Type	Value
attribute	NC_GLOBAL	_CoordSysBuilder	String	ucar.nc2.internal.dataset.conv.CF1Convention
attribute	NC_GLOBAL	acknowledgement	String	The Historical Sea Ice Atlas was a joint project funded by the Alaska Ocean Observing System (AOOS), the Alaska Center for Climate Assessment and Policy (ACCAP) and the Scenarios Network for Alaska and Arctic Planning (SNAP). This work was funded by the National Ocean Service at the National Oceanic and Atmospheric Administration (NOAA) through AOOS grant #NA11NOS0120020. Work was performed at UAF by the International Arctic Research Center's ACCAP (funded by the NOAA Office of Oceanic and Atmospheric Research) and SNAP, with assistance from the University of Illinois, Urbana-Champaign.
attribute	NC_GLOBAL	cdm_data_type	String	Grid
attribute	NC_GLOBAL	Conventions	String	CF-1.6, COARDS, Unidata Dataset Discovery v1.0
attribute	NC_GLOBAL	creator_email	String	takurkowski at alaska.edu
attribute	NC_GLOBAL	creator_name	String	Tom Kurkowski
attribute	NC_GLOBAL	creator_url	String	http://www.snap.uaf.edu/
attribute	NC_GLOBAL	date_created	String	2022-02-01T22:58:00Z
attribute	NC_GLOBAL	date_issued	String	2022-02-01T22:58:00Z
attribute	NC_GLOBAL	Easternmost_Easting	double	-119.875
attribute	NC_GLOBAL	GDAL	String	GDAL 2.2.1, released 2017/06/23
attribute	NC_GLOBAL	GDAL_AREA_OR_POINT	String	Area
attribute	NC_GLOBAL	geospatial_lat_max	double	80.125
attribute	NC_GLOBAL	geospatial_lat_min	double	40.125
attribute	NC_GLOBAL	geospatial_lat_resolution	double	0.25
attribute	NC_GLOBAL	geospatial_lat_units	String	degrees_north
attribute	NC_GLOBAL	geospatial_lon_max	double	-119.875
attribute	NC_GLOBAL	geospatial_lon_min	double	-179.875
attribute	NC_GLOBAL	geospatial_lon_resolution	double	0.25
attribute	NC_GLOBAL	geospatial_lon_units	String	degrees_east
attribute	NC_GLOBAL	history	String	Tue Feb 01 13:52:51 2022: GDAL CreateCopy( nc/seaice_conc_sic_mean_pct_monthly_ak_1850_01.nc, ... )
attribute	NC_GLOBAL	id	String	seaiceatlas
attribute	NC_GLOBAL	infoUrl	String	???
attribute	NC_GLOBAL	institution	String	???
attribute	NC_GLOBAL	keywords	String	alaska, concentration, data, distribution, estimates, ice, ice distribution, local, monthly, observed, sea, source, waters
attribute	NC_GLOBAL	license	String	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.
attribute	NC_GLOBAL	Metadata_Conventions	String	CF-1.6, COARDS, Unidata Dataset Discovery v1.0
attribute	NC_GLOBAL	metadata_link	String	http://seaiceatlas.snap.uaf.edu/
attribute	NC_GLOBAL	model	String	SNAP Sea Ice Atlas
attribute	NC_GLOBAL	naming_authority	String	edu.uaf.snap
attribute	NC_GLOBAL	Northernmost_Northing	double	80.125
attribute	NC_GLOBAL	processing_level	String	This data set includes weekly (January 1954 to December 2013) and monthly (January 1850 to December 2020) midpoint historical sea ice concentration (0 - 100%) estimates at 1/4 x 1/4 degree spatial resolution for the ocean region around the state of Alaska, USA. This value-added dataset was developed by compiling the below historical data sources into spatially and temporally standardized datasets. Gaps in temporal or spatial resolutions were filled in with spatial and temporal analog month approaches. Note the monthly values from January 1954 - December 2013 are the week 2 values from the weekly time series. They are provided in the monthly time series for ease of use in monthly midpoint analyses. The January 2014 - February 2017 monthly time series data have been regridded and processed to match the January 1954 - December 2013 series from the NSIDC 0051 Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 1, which were accessed from the NSIDC website (https://nsidc.org/data/docs/daac/nsidc0051_gsfc_seaice.gd.html). The further post-processing and regridding of the NSIDC product to the extent / crs / origin / resolution of the existing data, was a non-standard process. It involved initially warping the polar stereographic data to a pacific centered WGS84 crs, converting the sea ice concentration values to points and performing a spline interpolation across the entire domain. This interpolated raster was then filled further around the land-sea divide where there was a mismatch between the NSIDC mask and the Sea Ice Atlas mask. The filling was performed by taking the average of the surrounding sea ice concentration pixels and filling the missing locations. These locations have been flagged in the source band (band 2) to keep track of what was modified from the NSIDC 0051 for this purpose. These data are a compilation of data from many sources integrated into a single gridded product. The sources of data for each grid cell have changed over the years from infrequent land/sea observations, to observationally derived charts, to satellite data for the most recent decades. Temporal and spatial gaps within observed data are filled with analog month approaches. Please note that large portions of the pre-1953, and almost all of the pre-1900 data, are either analog or interpolated data and the user is cautioned to use these data with care. The temporal and spatial inhomogeneities in the data sources that went into the construction of this dataset require that any historical analysis of the data is done with caution and an understanding of the limitations of the data. Methods of data compilation varied by data source, but included visual interpretation of hard copy map notation and legends, scanning, digitization, geo-rectification into digital geospatial products, reprojection, and also resampling into a common resolution. To standardize the data onto a common spatial grid, the resampling methodology utilized the centroid of the target 1/4 x 1/4 grid cell as the location to extract the value from the underlying data source.
attribute	NC_GLOBAL	project	String	Historical Sea Ice Atlas
attribute	NC_GLOBAL	publisher_email	String	janzen at aoos.org
attribute	NC_GLOBAL	publisher_institution	String	Alaska Ocean Observing System
attribute	NC_GLOBAL	publisher_name	String	Alaska Ocean Observing System
attribute	NC_GLOBAL	publisher_url	String	http://www.aoos.org
attribute	NC_GLOBAL	sourceUrl	String	(local files)
attribute	NC_GLOBAL	Southernmost_Northing	double	40.125
attribute	NC_GLOBAL	standard_name_vocabulary	String	CF-12
attribute	NC_GLOBAL	summary	String	Data from a local source.
attribute	NC_GLOBAL	time_coverage_end	String	2018-12-15T12:00:00Z
attribute	NC_GLOBAL	time_coverage_start	String	1850-01-15T12:00:00Z
attribute	NC_GLOBAL	title	String	Data from a local source.
attribute	NC_GLOBAL	Westernmost_Easting	double	-179.875
dimension	time		double	nValues=2028, evenlySpaced=false, averageSpacing=30 days 10h 28m 43s
attribute	time	_ChunkSizes	uint	1024
attribute	time	_CoordinateAxisType	String	Time
attribute	time	actual_range	double	-3.7855728E9, 1.5448752E9
attribute	time	axis	String	T
attribute	time	calendar	String	gregorian
attribute	time	ioos_category	String	Time
attribute	time	long_name	String	Time
attribute	time	standard_name	String	time
attribute	time	time_origin	String	01-JAN-1970 00:00:00
attribute	time	units	String	seconds since 1970-01-01T00:00:00Z
dimension	latitude		double	nValues=161, evenlySpaced=true, averageSpacing=0.25
attribute	latitude	_ChunkSizes	uint	40
attribute	latitude	_CoordinateAxisType	String	Lat
attribute	latitude	actual_range	double	40.125, 80.125
attribute	latitude	axis	String	Y
attribute	latitude	ioos_category	String	Location
attribute	latitude	long_name	String	Latitude
attribute	latitude	standard_name	String	latitude
attribute	latitude	units	String	degrees_north
dimension	longitude		double	nValues=241, evenlySpaced=true, averageSpacing=0.25
attribute	longitude	_ChunkSizes	uint	60
attribute	longitude	_CoordinateAxisType	String	Lon
attribute	longitude	actual_range	double	-179.875, -119.875
attribute	longitude	axis	String	X
attribute	longitude	ioos_category	String	Location
attribute	longitude	long_name	String	Longitude
attribute	longitude	standard_name	String	longitude
attribute	longitude	units	String	degrees_east
variable	sic_con_pct		float	time, latitude, longitude
attribute	sic_con_pct	_ChunkSizes	uint	10, 40, 60
attribute	sic_con_pct	_FillValue	float	-2.14748365E9
attribute	sic_con_pct	colorBarMaximum	double	100.0
attribute	sic_con_pct	colorBarMinimum	double	0.0
attribute	sic_con_pct	grid_mapping	String	crs
attribute	sic_con_pct	ioos_category	String	Ice Distribution
attribute	sic_con_pct	long_name	String	Sea Ice Concentration
attribute	sic_con_pct	units	String	percent

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.