How much water plants and soil release, gap-filled (VIIRS, NOAA-20)

In plain English

What it measures. Maps of evapotranspiration, the water released into the air by plants and soil, plus the potential amount under ideal conditions, in 8-day composites at 500-meter detail across the globe. The gaps from poor-quality data have been filled in.

How it's made. Calculated from the VIIRS instrument on the NOAA-20 satellite using a standard evaporation equation fed with daily weather data and satellite vegetation and surface measurements, then gap-filled at the end of each year.

How & where you'd use it. Supports water-use, drought, and agriculture studies. Because the gap-filling happens only once a full year is available, it is not suited to real-time needs.

What's measured

ATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROCESSES › EVAPOTRANSPIRATIONATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROCESSES › EVAPORATIONATMOSPHERE › PRECIPITATION › PRECIPITATION PROFILES › LATENT HEAT FLUX

Coverage & cadence

Time span2018-01-01 → ongoing
Measured byNOAA-20 (VIIRS)
Processing levelLevel 4
Spatial extent-180, -90, 180, 90
FormatsHDF-EOS5
StatusACTIVE

What you can do with it

Map air pollutants — NO₂, aerosols, ozone
Track greenhouse gases and Earth's energy budget
Feed weather and air-quality analysis

Official description

The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Actual and Potential Evapotranspiration product is a gap-filled 8-day composite dataset produced at 500 meter (m) pixel resolution. The VIIRS ET and PET algorithm is based on the Penman-Monteith equation, which includes inputs of daily meteorological reanalysis data along with VIIRS remotely sensed data products such as 8-day vegetation property dynamics and daily surface albedo. The VJ116A2GF will be generated at the end of each year when the entire yearly 8-day VJ115A2H is available. Hence, the gap-filled VJ116A2GF is the improved VJ116A2, which has cleaned the poor-quality inputs from 8-day Leaf Area Index and Fraction of Photosynthetically Active Radiation (LAI/FPAR) based on the Quality Control (QC) label for every pixel. If any LAI/FPAR pixel did not meet the quality screening criteria, its value is determined through linear interpolation. However, users cannot get VJ116A2GF in near-real time because it will be generated only at the end of a given year. Provided in the VJ116A2GF product are layers for composited Evapotranspiration (ET), Latent Heat Flux (LE), Potential ET (PET) and Potential LE (PLE) along with a quality control layer. Two low resolution browse images, ET and LE, are also available for each VJ116A2GF granule. The pixel values for the two Evapotranspiration layers (ET and PET) are the summation of 8-day total water loss within the composite period and the pixel values for the two Latent Heat layers (LE and PLE) are the average total energy over a unit area for a day during the composite period. Note that the last acquisition period of each year is a 5 or 6-day composite period, depending on the year. Known Issues * Please refer to the [VIIRS Land Products website](https://viirsland.gsfc.nasa.gov/Products/NASA/ET_ESDR.html) and [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS) for information about VJ116A2GF known issues.

Get the data

vj116a2gf_access.py

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

results = earthaccess.search_data(
    short_name="VJ116A2GF",
    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.

What's measured

Coverage & cadence

What you can do with it

Get the data

Official links