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Full catalog/VJ121A2
VJ121A2·v002·dataset

How hot the land surface gets, 8-day (VIIRS, NOAA-20, 1 km)

VIIRS/JPSS1 Land Surface Temperature/Emissivity 8-Day L3 Global 1km SIN Grid V002
land NASA LPCLOUD Level 3 active HDF-EOS5
In plain English

What it measures. How hot the land surface gets and how efficiently it radiates heat (emissivity), combined over 8-day periods, mapped globally at 1 km for both day and night.

How it's made. Built by averaging cloud-free daily land-surface temperature readings from the VIIRS instrument on the NOAA-20 satellite over each 8-day window, using methods matched to MODIS for continuity.

How & where you'd use it. Used to study heat patterns, urban heat, drought stress, and changing land conditions over time.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › EMISSIVITYLAND SURFACE › SURFACE THERMAL PROPERTIES › LAND SURFACE TEMPERATURE

Coverage & cadence

  • Time span2018-01-01 → ongoing
  • Measured byNOAA-20 (VIIRS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS5
  • StatusACTIVE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature and Emissivity (LST&E) 8-day product (VJ121A2) combines the daily [VJ121A1D](http://doi.org/10.5067/VIIRS/VJ121A1D.002) and [VJ121A1N](http://doi.org/10.5067/VIIRS/VJ121A1N.002) products over an 8-day compositing period into a single product. The VJ121A2 dataset is an 8-day composite LST&E product at 1 kilometer resolution that uses an algorithm based on a simple-averaging method. The algorithm calculates the average from all the cloud-free VJ121A1D and VJ121A1N daily acquisitions from the 8-day period. Unlike the VJ121A1 datasets where the daytime and nighttime acquisitions are separate products, the VJ121A2 contains both daytime and nighttime acquisitions as separate science dataset (SDS) variables within a single Hierarchical Data Format (HDF) file. The VJ121A2 product is developed synergistically with the Moderate Resolution Imaging Spectroradiometer (MODIS) LST&E Version 6.1 product ([MOD21A2](https://doi.org/10.5067/MODIS/MOD21A2.061)) using the same input atmospheric products and algorithmic approach. 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 VJ121A2 product contains 11 Science Datasets (SDS) variables: 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 VJ121A2 granule. Known Issues * For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS) and the User Guide.

Get the data

vj121a2_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VJ121A2",
    version="002",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LPCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.