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Description

The 8-day Visible Infrared Imaging Radiometer Suite (VIIRS) surface reflectance (VNP09A1) Version 2 composite product provides an estimate of land surface reflectance from the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS sensor for nine moderate resolution bands (M1 - M5, M7, M8, M10, M11) at nominal 1 kilometer resolution (~926 meter). The 1 kiliometer dataset is derived through resampling the native 750 meter VIIRS resolution in the Level 2 input product. The data are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. Each pixel represents the best possible Level 2G observation during an 8-day period that is selected on the basis of high observation coverage, low sensor angle, the absence of clouds or cloud shadow, and aerosol loading.

Included in the product along with the nine reflectance bands are day of year, reflectance band quality, control, reflectance state quality assurance, relative azimuth angle, sensor zenith angle, and solar zenith angle layers.

Known Issues

Improvements/Changes from Previous Versions

  • Improved calibration algorithm and coefficients for entire Suomi NPP mission.
  • Improved geolocation accuracy and applied updates to fix outliers around maneuver periods.
  • Corrected the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid- to high-latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VNP13 Vegetation Indices and VNP43 Bidirectional Reflectance Distribution Function (BRDF)/Albedo.
  • Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data.
  • Replaced the land/water mask input product with the eight-class land/water mask from the VNP03 geolocation product that better aligns with MODIS.
  • Added secondary day-night flag to improve retrieval of Climate Modeling Grid (CMG) values over daytime pixels.
  • More details can be found in this VIIRS Land V2 Changes document.

Product Summary

Platforms
Suomi-NPP
Instruments
VIIRS
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
1000 Meters x 1000 Meters
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2012-01-01 to Present
Temporal Resolution
8 Day
Data Partner
Land Science Investigator-led Processing System, Terrestrial Information Systems Laboratory, Earth Sciences Division, Sciences and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/LandSIPS) ,
Land Processes Distributed Active Archive Center (LP DAAC)
Concept ID
C2519124793-LPCLOUD
Data State
ACTIVE
Number of Files/Granules
182178
Processing Level
3
Published
Updated
Science Keywords
Reflectance

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Vermote, E., Franch, B., & Claverie, M. (2023). VIIRS/NPP Surface Reflectance 8-Day L3 Global 1km SIN Grid V002 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/VIIRS/VNP09A1.002 Date Accessed: 2025-12-13

File Naming Convention

VNP09A1.A2025209.h10v11.002.2025218154856.h5

The file name begins with the Product Short Name (VNP09A1) followed by the Julian Date of Acquisition formatted as AYYYYDDD (A2025209), the Tile Identifier which is horizontal tile and vertical tile provided as hXXvYY (h10v11), the Version of the data collection (002), the Julian Date and Time of Production designated as YYYYDDDHHMMSS (2025218154856), and the Data Format (h5).

Documents

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Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
RelativeAzimuth Relative Azimuth Angle Degree int16 0 -18000 to 18000 0.01
SensorZenith SensorZenith Angle Degree int16 0 0 to 18000 0.01
SolarZenith Solar Zenith Angle Degree int16 0 0 to 18000 0.01
SurfReflect_Day_Of_Year Day of Year Julian day uint16 65535 1 to 366 N/A
SurfReflect_M1_1 1 km Surface Reflectance Band M1 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M2_1 1 km Surface Reflectance Band M2 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M3_1 1 km Surface Reflectance Band M3 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M4_1 1 km Surface Reflectance Band M4 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M5_1 1 km Surface Reflectance Band M5 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M7_1 1 km Surface Reflectance Band M7 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M8_1 1 km Surface Reflectance Band M8 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M10_1 1 km Surface Reflectance Band M10 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_M11_1 1 km Surface Reflectance Band M11 N/A int16 -28672 -100 to 16000 0.0001
SurfReflect_QC Surface Reflectance Band Quality Control (QC) Bit Field uint32 4294967295 0 to 2147483647 N/A
SurfReflect_State Surface Reflectance State Quality Assurance (QA) Bit Field uint16 65535 0 to 13311 N/A
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