Earth Data School
About
Full catalog/CLDMSK_L2_MODIS_Aqua
CLDMSK_L2_MODIS_Aqua·v1·dataset

Where clouds are blocking the view (Aqua, 1 km)

MODIS/Aqua Cloud Mask 5-Min Swath 1000 m
atmosphere NASA LAADS Level 2 active NetCDF-4
In plain English

What it measures. For each spot the sensor sees, how confident the algorithm is that the view of the surface is unobstructed by cloud, at 1-kilometer resolution.

How it's made. Generated from the Aqua MODIS instrument using a cloud-detection method deliberately designed to match the VIIRS version, so cloud records stay consistent across instruments.

How & where you'd use it. A filtering layer that other products use to remove cloudy pixels and keep clear-sky data. Most people use it indirectly through the surface and temperature products that depend on it.

What's measured

ATMOSPHERE › CLOUDSATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD FREQUENCYATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD HEIGHTSPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › INFRARED RADIANCESPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › REFLECTED INFRAREDSPECTRAL/ENGINEERING › VISIBLE WAVELENGTHS › VISIBLE RADIANCE

Coverage & cadence

  • Time span2002-07-04 → ongoing
  • Measured byAqua (MODIS)
  • 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 MODIS-VIIRS Cloud Mask (MVCM) is designed to facilitate continuity in cloud detection between the MODIS (Moderate Resolution Imaging Spectroradiometer) on the Aqua and Terra platforms and the series of VIIRS (Visible Infrared Imaging Radiometer Suite) instruments, beginning with the Suomi NPP spacecraft. To establish continuity, this MODIS MVCM product does not use an algorithm identical to that used in the standard MODIS product (MOD35/MYD35). The MVCM-MODIS Cloud Mask product is Aqua MOIDS Level-2, 5-Min Swath product generated at 1000 m (at nadir) spatial resolution. The algorithm employs a series of visible through infrared threshold and consistency tests to specify confidence that an unobstructed view of the Earth's surface has been observed. Radiometrically-accurate radiances are required, thus holes in the cloud mask will appear wherever the input radiances are incomplete or of poor quality. For more information consult Product Page at: https://cimss.ssec.wisc.edu/MVCM/

Get the data

cldmsk_l2_modis_aqua_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="CLDMSK_L2_MODIS_Aqua",
    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.