HDF5 file, superblock version 0
group /
	attribute Conventions = "CF-1.5"
	attribute GDAL = "GDAL 2.2.3, released 2017/11/20"
	attribute NCO = "4.7.2"
	attribute contact = "vludwig@uni-bremen.de"
	attribute creation_date = "2023-10-11 16:27:38"
	attribute datatype = "8-bit integer."
	attribute description = " Thermal infrared (MODIS-Aqua) and passive microwave (AMSR2-GCOM_W1) satellite data provide complementary observations of sea ice concentration (SIC): Thermal infrared data have a high spatial resolution (1 km), but are only available in cloud-free conditions. The thermal infrared SIC is determined based on the local temperature anomaly using the basic algorithm presented in Druee and Heinemann (2004, GRL) and the improvements presented in Ludwig et al (2019,2020). AMSR2 data have a lower spatial resolution (5 km for the 89 GHz channels), but are available independently of cloud cover. The 89 GHz ASI algorithm (Spreen et al, 2008, JGR Oceans) is used for the passive microwave SIC. The merging is done in the following way: A 5x5 km box, roughly corresponding to one passive microwave footprint, is selected. In this box, the thermal infrared SIC are tuned such that their mean is equivalent to the passive microwave SIC, but their distribution is preserved. This ensures that the SIC is consistent at the transition between cloud-free and cloudy pixels. Pixels where no thermal infrared SIC are available due to cloud coverage are filled by the passive microwave SIC. In this case, the actual resolution goes down to 5 km. Since both satellites are in the A-train satellite constellation, the timelag between the observations is in the order of minutes. For each overflight, thermal infrared and passive microwave SIC are calculated separately. Subsequently, the merging is done. Once the merged SIC have been calculated for all overflights, the daily mean is calculated. "
	attribute description_sic_amsr2 = "Uncertainty of AMSR2 SIC"
	attribute description_sic_merged = "Daily mean merged SIC."
	attribute description_sic_modis = "Uncertainty of MODIS SIC"
	attribute description_unc_sic_merged = "Uncertainty of merged SIC"
	attribute epsg = 3411
	attribute fill_value_int8 = 101
	attribute grid = "NSIDC grid (polar stereographic, latitude of true scale 70N, documentation: http://nsidc.org/data/polar-stereo/ps_grids.html, resolution 1 km). "
	attribute institution = "University of Bremen, Institute for Environmental Physics"
	attribute land_value_int8 = 127
	attribute ll_lat = 57.2528954
	attribute ll_lon = -91.807274
	attribute proj4string = "+proj=stere +a=6378273.0 +b=6356889.449 +units=m +lat_0=90.0 +lat_ts=70.0 +lon_0=315.0 +x_0=2656249.8497792133 +y_0=2493750.112961679"
	attribute quantity = " Merged sea ice concentration from MODIS thermal infrared and AMSR2 passive microwave observations."
	attribute reference = "Ludwig, V., Spreen, G., Pedersen, L.T.: Evaluation of a New Merged Sea-Ice Concentration Dataset at 1 km Resolution from Thermal Infrared and Passive Microwave Satellite Data in the Arctic. Remote Sens. 2020, 12, 3183, doi.org/10.3390/rs12193183 "
	attribute spatial_resolution = "1 km"
	attribute statement_acknowledgements = "If you use this dataset in a publication, please refer to Ludwig et al. (2020) in the text. The reference is given in the metadata. Also, please put the following or an equivalent statement into the Acknowledgements: We thank the Institute of Environmental Physics, University of Bremen for the provision of the merged MODIS&AMSR2 sea-ice concentration dataset at https://seaice.uni-bremen.de/data/modis_amsr2 (last access [date_of_last_access]). "
	attribute swath_data = " Available upon request: vludwig@uni-bremen.de"
	attribute temporal_resolution = "Daily mean"
	attribute units = "Percentage"
	attribute ur_lat = 56.9475822
	attribute ur_lon = 82.8237686
dataset /polar_stereographic: string(1), shape ()
	attribute GeoTransform = "-2655829.340054836 1000.089796270335 0 2256790.894610822 0 -1000.000048054012 "
	attribute false_easting = 0.0
	attribute false_northing = 0.0
	attribute grid_mapping_name = "polar_stereographic"
	attribute inverse_flattening = 298.279411123064
	attribute latitude_of_projection_origin = 90.0
	attribute long_name = "CRS definition"
	attribute longitude_of_prime_meridian = 0.0
	attribute semi_major_axis = 6378273.0
	attribute spatial_ref = "PROJCS[\"NSIDC Sea Ice Polar Stereographic North\",GEOGCS[\"Unspecified datum based upon the Hughes 1980 ellipsoid\",DATUM[\"Not_specified_based_on_Hughes_1980_ellipsoid\",SPHEROID[\"Hughes 1980\",6378273,298.279411123064,AUTHORITY[\"EPSG\",\"7058\"]],AUTHORITY[\"EPSG\",\"6054\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4054\"]],PROJECTION[\"Polar_Stereographic\"],PARAMETER[\"latitude_of_origin\",70],PARAMETER[\"central_meridian\",-45],PARAMETER[\"scale_factor\",1],PARAMETER[\"false_easting\",0],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AXIS[\"X\",EAST],AXIS[\"Y\",NORTH],AUTHORITY[\"EPSG\",\"3411\"]]"
	attribute standard_parallel = 70.0
	attribute straight_vertical_longitude_from_pole = -45.0
dataset /sic_amsr2: int8, shape (4750, 5560)
dataset /sic_merged: int8, shape (4750, 5560)
dataset /sic_modis: int8, shape (4750, 5560)
dataset /unc_sic_merged: int8, shape (4750, 5560)
dataset /x: float64, shape (5560)
	attribute long_name = "x coordinate of projection"
	attribute standard_name = "projection_x_coordinate"
	attribute units = "m"
// x: first -2655329.295156701, last 2904169.8823100924, count 5560
dataset /y: float64, shape (4750)
	attribute long_name = "y coordinate of projection"
	attribute standard_name = "projection_y_coordinate"
	attribute units = "m"
// y: first -2492709.333621706, last 2256290.894586795, count 4750