The NASA Suomi National Polar-Orbiting Partnership (Suomi NPP) Visible
Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature and
Emissivity (LST&E) Night Version 1 product (VNP21A1N) is compiled daily
from nighttime Level 2 Gridded (L2G) intermediate products.
The L2G process maps the daily VNP21 swath granules onto a sinusoidal MODIS
grid and stores all observations overlapping a gridded cell for a given
night. The VNP21A1 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. Only observations having
observation coverage more than a certain threshold (15%) are considered for
this averaging.
0: Pixel produced, good quality, no further QA info necessary
1: Pixel produced but unreliable quality
2: Pixel not produced due to cloud
3: Pixel not produced due to reasons other than cloud
Bits 2-3: Data quality flag
0: Good data quality of L1B bands 14, 15, 16
1: Missing pixel
2: Fairly calibrated
3: Poorly calibrated, TES processing skipped
Bits 4-5: Cloud Flag
0: Cloud-free
1: Thin cirrus
2: Pixel within 2 pixels of nearest cloud
3: Cloudy pixels
Bits 6-7: Iterations
0: Slow convergence
1: Nominal
2: Nominal
3: Fast
Bits 8-9: Atmospheric Opacity
0: ≥3 (Warm, humid air; or cold land)
1: 0.2 - 0.3 (Nominal value)
2: 0.1 - 0.2 (Nominal value)
3: <0.1 (Dry, or high altitude pixel)
Bits 10-11: MMD
0: >0.15 (Most silicate rocks)
1: 0.1 - 0.15 (Rocks, sand, some soils)
2: 0.03 - 0.1 (Mostly soils, mixed pixel)
3: <0.03 (Vegetation, snow, water, ice, some soils)
Bits 12-13: Emissivity accuracy
0: >0.02 (Poor performance)
1: 0.015 - 0.02 (Marginal performance)
2: 0.01 - 0.015 (Good performance)
3: <0.01 (Excellent performance)
Bits 14-15: LST accuracy
0: >2K (Poor performance)
1: 1.5 - 2K (Marginal performance)
2: 1 - 1.5K (Good performance)
3: <1K (Excellent performance)
Emis_14
Daily M14 emissivity
Emis_15
Daily M15 emissivity
Emis_16
Daily M16 emissivity
View_Angle
deg
View zenith angle of LST
View_Time
h
Time of LST observation
Terms of Use
Terms of Use
LP DAAC NASA data are freely accessible; however, when an author
publishes these data or works based on the data, it is requested that the
author cite the datasets within the text of the publication and include a
reference to them in the reference list.
The NASA Suomi National Polar-Orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature and Emissivity (LST&E) Night Version 1 product (VNP21A1N) is compiled daily from nighttime Level 2 Gridded (L2G) intermediate products. The L2G process maps the daily VNP21 swath granules onto a sinusoidal MODIS grid …
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],[],[[["This dataset, NOAA/VIIRS/001/VNP21A1N, has been superseded by a newer version, NASA/VIIRS/002/VNP21A1N, and is considered deprecated."],["It provides daily nighttime land surface temperature and emissivity data at a 1km resolution, derived from the Suomi NPP VIIRS instrument."],["The data covers the period from January 19, 2012, to May 1, 2024, and is freely accessible through NASA's LP DAAC."],["Users are encouraged to cite the dataset appropriately in publications using guidelines provided on the LP DAAC website."],["The dataset can be explored and analyzed using Google Earth Engine, a platform for geospatial data analysis and visualization."]]],[]]