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Full catalog/WATVP_L2_VIIRS_SNPP
WATVP_L2_VIIRS_SNPP·v1·dataset

How much water vapor is in the air (VIIRS, 750 m)

VIIRS/SNPP Level-2 Water Vapor Products 6-min Swath 750m
atmosphere NASA LAADS Level 2 active NetCDF-4
In plain English

What it measures. Reports how much water vapor is in the whole column of air above each spot, at fairly fine detail. Water vapor is the invisible moisture in the air that feeds clouds and rain.

How it's made. Created by blending infrared readings from the VIIRS instrument on the Suomi-NPP satellite with moisture soundings from companion instruments, since VIIRS lacks dedicated water vapor channels.

How & where you'd use it. Useful for weather analysis and tracking moisture in the atmosphere, continuing a long record that earlier MODIS instruments began.

What's measured

ATMOSPHERE › ATMOSPHERIC WATER VAPORATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORSATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORS › HUMIDITYATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORS › TOTAL PRECIPITABLE WATERATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORS › WATER VAPORATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROFILES

Coverage & cadence

  • Time span2012-05-01 → ongoing
  • Measured bySuomi-NPP (VIIRS)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsNetCDF-4
  • StatusCOMPLETE

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 Suomi NPP VIIRS Water Vapor Products provide total column water vapor (TPW) properties from merged VIIRS infrared measurements and CrIS plus ATMS water vapor soundings to continue the depiction of global moisture at high spatial resolution started with MODIS on the Terra and Aqua platforms. While MODIS has two water vapor channels within the 6.5 μm H2O absorption band and four channels within the 15 micrometer CO2 absorption band, VIIRS has no channels in either IR absorption band. The VNPWATVP algorithm is similar to the MODIS MOD07 synthetic regression algorithm. It uses the three VIIRS longwave IR window bands in a regression relation and adds the NUCAPS (CrIS+ATMS) water vapor product to compensate for the absence of VIIRS water vapor channels. The Level-2 6-minute granule and 750 m spatial resolution VIIRS TPW product file includes the collocated NUCAPS background TPW, the VIIRS-only TPW, and VIIRS+NUCAPS TPW retrievals with quality flags.

Get the data

watvp_l2_viirs_snpp_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="WATVP_L2_VIIRS_SNPP",
    version="1",
    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 LAADS
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.