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Description

The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature and Emissivity (LST&E) Climate Modeling Grid Version 2 product (VJ121C) is compiled daily from daytime Level 2 Gridded (L2G) intermediate products. The L2G process maps the daily VJ121 swath granules onto a sinusoidal MODIS grid and stores all observations overlapping a gridded cell for a given day. The VJ121C1 algorithm sorts through all these observations for each cell and estimates the final LST value as an average from all cloud-free observations that have good LST accuracies. The 0.05 degree (5,600 m) dataset is derived through resampling the native 750 meter VIIRS resolution in the input product.

The overall objective for NASA VIIRS products is to ensure the algorithms and products are compatible with the MODIS Terra and Aqua algorithms to promote the continuity of the Earth Observation System (EOS) mission. Additional details regarding the method used to create this Level 3 (L3) product are available in the Algorithm Theoretical Basis Document (ATBD).

The VJ121C1 product contains 25 Science Datasets (SDS): LST, quality control, view zenith angle, and time of observation for both day and night observations along with emissivity for bands M14, M15, and M16. Low-resolution browse images for day and night LST are also available for each VJ121C1 granule.

Known Issues

Improvements/Changes from Previous Version

  • Improved calibration algorithm and coefficients for entire NOAA-20 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.
  • Replaced MERRA2 inputs with GEOS5.
  • Included inland water body pixels to allow for LST retrieval over these areas.
  • Introduced daily, 8-day, and monthly LST CMG products.
  • More details can be found in this VIIRS Land V2 Changes document.

Version Description

Collection Version 2 Processing and Reprocessing

Product Summary

Platforms
NOAA-20
Instruments
VIIRS
Spatial Extent
N: 90 S: -90 E: 180 W: -180
Spatial Resolution
5600 Meters x 5600 Meters
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2018-01-01 to Present
Temporal Resolution
1 Day
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
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)
Concept ID
C2545310901-LPCLOUD
Data State
ACTIVE
Processing Level
3
Published
Updated
Science Keywords
Emissivity,
Land Surface Temperature

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

Hulley, G., & Hook, S. (2023). VIIRS/JPSS1 Land Surface Temperature/Emissivity Daily L3 Global 0.05Deg CMG V002 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/VIIRS/VJ121C1.002 Date Accessed: 2025-11-02

File Naming Convention

VJ121C1.A2025222.002.2025223125632.h5

The file name begins with the Product Short Name (VJ121C1) followed by the Julian Date of Acquisition formatted as AYYYYDDD (A2025222), the Version of the data collection (002), the Julian Date and Time of Production designated as YYYYDDDHHMMSS (2025223125632), and the Data Format (h5).

Documents

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
Count_Day Count of Daytime Input Values N/A uint16 0 0 to 65535 N/A
Count_Night Count of Nighttime Input Values N/A uint16 0 0 to 65535 N/A
Day_view_angle Average Daytime View Zenith Angle Degree uint8 255 255 to 130 N/A
Day_view_time Average Daytime View Time Hours uint8 255 255 to 240 0.2
Emis_14_Day Average Daytime Band 14 Emissivity N/A uint8 0 0 to 255 0.002
Emis_14_Day_err Root-mean-square-error Daytime Band 14 Emissivity N/A uint16 0 0 to 65535 0.0001
Emis_14_Night Average Nighttime Band 14 Emissivity N/A uint8 0 0 to 255 0.002
Emis_14_Night_err Root-mean-square-error Nighttime Band 14 Emissivity N/A uint16 0 0 to 65535 0.0001
Emis_15_Day Average Daytime Band 15 Emissivity N/A uint8 0 0 to 255 0.002
Emis_15_Day_err Root-mean-square-error Daytime Band 15 Emissivity N/A uint16 0 0 to 65535 0.0001
Emis_15_Night Average Nighttime Band 15 Emissivity N/A uint8 0 0 to 255 0.002
Emis_15_Night_err Root-mean-square-error Nighttime Band 15 Emissivity N/A uint16 0 0 to 65535 0.0001
Emis_16_Day Average Daytime Band 16 Emissivity N/A uint8 0 0 to 255 0.002
Emis_16_Day_err Root-mean-square-error Daytime Band 16 Emissivity N/A uint16 0 0 to 65535 0.0001
Emis_16_Night Average Nighttime Band 16 Emissivity N/A uint8 0 0 to 255 0.002
Emis_16_Night_err Root-mean-square-error Nighttime Band 16 Emissivity N/A uint16 0 0 to 65535 0.0001
LST_Day Average Daytime Land Surface Temperature Kelvin uint16 0 0 to 65535 0.02
LST_Day_err Root-mean-square-error Daytime Land Surface Temperature Kelvin uint8 0 0 to 255 0.04
LST_Night Average Nighttime Land Surface Temperature Kelvin uint16 0 0 to 65535 0.02
LST_Night_err Root-mean-square-error Nighttime Land Surface Temperature Kelvin uint8 0 0 to 255 0.04
Night_view_angle Average Nighttime View Zenith Angle Degree uint8 255 255 to 130 N/A
Night_view_time Average Nighttime View Time Hours uint8 255 255 to 240 0.2
Percent_land_in_grid Percent of Land Detections in Grid Cell Percent uint8 255 255 to 100 N/A
QC_Day Quality Control for Daytime LST and Emissivity N/A uint8 0 0 to 255 N/A
QC_Night Quality Control for Nighttime LST and Emissivity N/A uint8 0 0 to 255 N/A
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