VNP10 Product File Specification
Version: V1.0.0
Revision: 0
Date: 22 January 2019
ESDT: VNP10
Product name: Snow Cover
Product Level: 2
PGE: 507
Point of Contact: George Riggs
SSAI
NASA, GSFC, Code 971
Greenbelt, MD 20771
301-614-5650
George.A.Riggs.1@gsfc.nasa.gov
Principal Investigator: Dorothy K. Hall
NASA, GSFC, Code 971
Greenbelt, MD 20771
301-614-5771
Dorothy.K.Hall@nasa.gov
Co-Investigator: George Riggs
SSAI
NASA, GSFC, Code 971
Greenbelt, MD 20771
301-614-5650
George.A.Riggs.1@gsfc.nasa.gov
Description:
This data set reports the location of snow cover using radiance data acquired by the Visible Infrared Imager Radiometer Suite
(VIIRS) on board the Suomi National Polar-orbiting Partnership (NPP) satellite. Snow cover is identified using the Normalized
Difference Snow Index (NDSI) and a series of quality control screens.
Snow covered land typically has a very high reflectance in visible bands and very low reflectance in the shortwave infrared.
The Normalized Difference Snow Index (NDSI) reveals the magnitude of this difference, with values greater than 0 typically
indicating the presence of at least some snow. The algorithm for this data set calculates NDSI using VIIRS image bands I1
(0.64 µm, visible red) and I3 (1.61 µm, shortwave near-infrared) and then applies a series of data screens designed to alleviate
likely errors and flag uncertain snow detections.
The data product and algorithm are described in the VIIRS Snow Cover Data Product User Guide. The user should refer to that
document for detailed description of the product, how to interpret the product and attributes (metadata). Other information
may be found at https://nsidc.org/data/VNP10
SDSs produced:
Algorithm_bit_flags_QA
Basic_QA
NDSI
NDSI_Snow_Cover
latitude
longitude
Contents:
Global Metadata:
Name: Type: Num_Val: Source: Value:
AlgorithmType STRING 1 STIG "OPS"
AlgorithmVersion STRING 1 STIG Variable
Conventions STRING 1 STIG Variable
DayNightFlag STRING 1 STIG "Day"
EastBoundingCoord FLOAT 1 STIG Variable
WestBoundingCoord FLOAT 1 STIG Variable
NorthBoundingCoord FLOAT 1 STIG Variable
SouthBoundingCoord FLOAT 1 STIG Variable
GRingPointLongitude DOUBLE 4 PGE Variable
GRingPointLatitude DOUBLE 4 PGE Variable
RangeEndingDate STRING 1 PGE Variable
RangeEndingTime STRING 1 PGE Variable
RangeBeginningDate STRING 1 PGE Variable
RangeBeginningTime STRING 1 PGE Variable
StartTime STRING 1 PGE Variable
EndTime STRING 1 PGE Variable
InputPointer STRING 3 PGE Variable
InstrumentShortname STRING 1 PGE "VIIRS"
LocalGranuleID STRING 1 PGE Variable
LongName STRING 1 STIG "VIIRS/NPP Snow Cover 6-Min L2 Swath 375m"
PGEVersion STRING 1 PGE Variable
PGE_EndTime STRING 1 PGE Variable
PGE_Name STRING 1 PGE "PGE507"
PGE_StartTime STRING 1 PGE Variable
ProcessCenter STRING 1 STIG "LandSIPS"
ProcessingEnvironment STRING 1 PGE Variable
QAPercentBestQuality STRING 1 PGE Variable
QAPercentCloudCover STRING 1 PGE Variable
QAPercentGoodQuality STRING 1 PGE Variable
QAPercentOtherQuality STRING 1 PGE Variable
QAPercentPoorQuality STRING 1 PGE Variable
SatelliteInstrument STRING 1 PGE "NPP_OPS"
ShortName STRING 1 MCF "VNP10"
VersionID STRING 1 PGE Variable
cdm_data_type STRING 1 PGE "swath"
creator_email STRING 1 PGE "modis-ops@lists.nasa.gov"
creator_name STRING 1 PGE "VIIRS Land SIPS Processing Group"
creator_url STRING 1 PGE "http://ladsweb.nascom.nasa.gov"
identifier_product_doi STRING 1 PGE "10.5067/VIIRS/VNP10.001"
identifier_product_doi_authority
STRING 1 PGE "http://dx.doi.org"
institution STRING 1 PGE "NASA Goddard Space Flight Center"
keywords_vocabulary STRING 1 PGE "NASA Global Change Master Directory (GCMD) Science Keywords"
license STRING 1 PGE "http://science.nasa.gov/earth-science/earth-science-data/data-information-policy/"
naming_authority STRING 1 PGE "gov.nasa.gsfc.VIIRSland"
processing_level STRING 1 PGE "Level 2"
project STRING 1 PGE "VIIRS Land SIPS Snow Cover Project"
publisher_email STRING 1 PGE "modis-ops@lists.nasa.gov"
publisher_name STRING 1 PGE "LAADS"
publisher_url STRING 1 PGE "http://ladsweb.nascom.nasa.gov"
stdname_vocabulary STRING 1 PGE "NetCDF Climate and Forecast (CF) Metadata Convention"
title STRING 1 STIG "VIIRS Snow Cover Data"
===============================================================================
SDS Name: latitude
Description: Latitude data
Number Type: DFNT_FLOAT32
Rank: 2
Dimension sizes:(6496,6400)
Dimension Names:
Dimension0: "number_of_lines"
Dimension1: "number_of_pixels"
SDS Attributes:
Name: Type: Num_val: Source: Value:
long_name STRING 1 PGE "Latitude data"
units STRING 1 PGE "degrees_north"
valid_range DFNT_FLOAT32 2 PGE -90.00000, 90.0000
_FillValue DFNT_FLOAT32 1 PGE -999.0000
===============================================================================
SDS Name: longitude
Description: Longitude data
Number Type: DFNT_FLOAT32
Rank: 2
Dimension sizes:(6496,6400)
Dimension Names:
Dimension0: "number_of_lines"
Dimension1: "number_of_pixels"
SDS Attributes:
Name: Type: Num_val: Source: Value:
long_name STRING 1 PGE "Longitude data"
units STRING 1 PGE "degrees_east"
valid_range DFNT_FLOAT32 2 PGE -180.00000, 180.0000
_FillValue DFNT_FLOAT32 1 PGE -999.0000
===============================================================================
SDS Name: NDSI_Snow_Cover
Description: Snow cover by NDSI
Number Type: DFNT_UINT8
Rank: 2
Dimension sizes:(6496,6400)
Dimension Names:
Dimension0: "number_of_lines"
Dimension1: "number_of_pixels"
SDS Attributes:
Name: Type: Num_val: Source: Value:
long_name STRING string length PGE "Snow cover by NDSI"
valid_range DFNT_UINT8 2 PGE 0,100
_FillValue DFNT_UNIT8 1 PGE 255
coordinates STRING 1 PGE "latitude longitude"
mask_meanings STRING 1 PGE "201=no decision, 211=night, 237=lake, 239=ocean, 250=cloud, 251=missing data, 253=bowtie trim, 254=L1B fill"
mask_values DFNT_UINT8 9 PGE 201, 211, 237, 239, 250, 251, 253, 254
===============================================================================
SDS Name: NDSI
Description: NDSI for land/inland water pixels
Number Type: DFNT_FLOAT32
Rank: 2
Dimension sizes:(6496,6400)
Dimension Names:
Dimension0: "number_of_lines"
Dimension1: "number_of_pixels"
SDS Attributes:
Name: Type: Num_val: Source: Value:
long_name STRING string length PGE "NDSI for land/inland water pixels"
valid_range DFNT_UINT8 2 PGE -1000,1000
scale_factor DFNT_FLOAT32 1 PGE 0.001
_FillValue DFNT_INT16 1 PGE 32767
coordinates STRING 1 PGE "latitude longitude"
mask_meanings STRING 1 PGE "21100=night, 23900=ocean, 25100=L1B_missing, 25200=L1B_unusable, 25300=bowtie_trim, 25400=L1B_fill"
mask_values DFNT_UINT8 9 PGE 21100, 23900, 25100, 25200, 25300, 25400
===============================================================================
SDS Name: Algorithm_bit_flags_QA
Description: Algorithm bit flags
Number Type: DFNT_UINT8
Rank: 2
Dimension sizes:(6496,6400)
Dimension Names:
Dimension0: "number_of_lines"
Dimension1: "number_of_pixels"
SDS Attributes:
Name: Type: Num_val: Source: Value:
long_name STRING string length PGE "Algorithm bit flags"
comment STRING string length PGE "Bit flags are set for select conditions detected by data screens in the algorithm, multiple flags may be set for a pixel.Default is all bits off"
valid_range DFNT_UING8 2 PGE 0,255
coordinates STRING 1 PGE "latitude longitude"
flag_masks STRING 1 PGE "1b, 2b, 4b, 8b, 16b, 32b, 64b, 128b"
flag_meanings STRING 1 PGE "inland_water_flag low_visible_screen low_NDSI_screen combined_surface_temperature_and_height_screen/flag spare high_SWIR_screen/flag spare solar_zenith_flag"
===============================================================================
SDS Name: Basic_QA
Description: Basic QA value
Number Type: DFNT_UINT8
Rank: 2
Dimension sizes:(6496,6400)
Dimension Names:
Dimension0: "number_of_lines"
Dimension1: "number_of_pixels"
SDS Attributes:
Name: Type: Num_val: Source: Value:
long_name STRING string length PGE "Basic QA value"
_FillValue DFNT_UNIT8 1 PGE 255
coordinates STRING 1 PGE "latitude longitude"
key STRING 1 PGE "0=good, 1=poor, 2=bad, 3=other"
mask_meanings STRING 1 PGE "211=night 239=ocean 250=cloud 252=no_decision 253=bowtie_trim"
mask_values DFNT_UINT8 7 PGE 211, 239, 250, 252, 253
valid_range DFNT_UINT8 2 PGE 0,3
===============================================================================
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