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Full catalog/AERDT_L2_VIIRS_NOAA21
AERDT_L2_VIIRS_NOAA21·v2.1·dataset

Haze, dust and smoke in the air (NOAA-21, 6 km)

NOAA21 VIIRS Dark Target Aerosol Level-2 6-Minute Swath 6 km V2.1
atmosphere NASA LAADS Level 2 active NetCDF-4
In plain English

What it measures. How much haze, dust, and smoke is in the air (a measure called aerosol optical thickness) over land and ocean, plus particle-size information over the ocean, refreshed every six minutes around the globe.

How it's made. Produced by the VIIRS instrument on the NOAA-21 satellite using the same 'Dark Target' method developed for NASA's earlier MODIS satellites, at roughly 6-km resolution.

How & where you'd use it. Useful for tracking air quality, dust storms, and smoke from fires, and for studying how airborne particles affect climate.

What's measured

ATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESSATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESS › ANGSTROM EXPONENTATMOSPHERE › AEROSOLSATMOSPHERE › AEROSOLS › AEROSOL PARTICLE PROPERTIES

Coverage & cadence

  • Time span2023-02-10 → ongoing
  • Measured byNOAA-21 (VIIRS)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsNetCDF-4
  • 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-21 Visible Infrared Imaging Radiometer Suite (VIIRS) NASA standard Level-2 (L2) dark target (DT) aerosol product provides satellite-derived measurements of Aerosol Optical Thickness (AOT) and their properties over land and ocean, and spectral AOT and their size parameters over oceans every 6 minutes, globally. The VIIRS incarnation of the DT aerosol product is based on the same DT algorithm that was developed and used to derive products from the Terra and Aqua missions’ Moderate Imaging Spectroradiometer (MODIS) instruments. Two separate and distinct DT algorithms exist. One helps retrieve aerosol information over ocean (dark in visible and longer wavelengths), while the second aids retrievals over vegetated/dark-soiled land (dark in the visible wavelengths). This orbit-level product (Short-name: AERDT_L2_VIIRS_NOAA21) has an at-nadir resolution of 6 km x 6 km, and progressively increases away from nadir given the sensor’s scanning geometry and Earth’s curvature. Viewed differently, this product’s resolution accommodates 8 x 8 native VIIRS moderate-resolution (M-band) pixels that nominally have ~750 m horizontal pixel size. Hence, the Level-2 Dark Target Aerosol Optical Thickness data product incorporates 64 (750 m) pixels over a 6-minute acquisition. Version 2.1 constitutes the first collection of the L2 Dark Target Aerosol product derived from the NOAA-21 VIIRS observations. For more information consult LAADS product description page at: https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/AERDT_L2_VIIRS_NOAA21 Or, Dark Target aerosol team Page at: https://darktarget.gsfc.nasa.gov/

Get the data

aerdt_l2_viirs_noaa21_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="AERDT_L2_VIIRS_NOAA21",
    version="2.1",
    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.