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Full catalog/MOD35_L2
MOD35_L2·v6.1·dataset

Where the clouds are, cloud mask (Terra)

MODIS/Terra Cloud Mask and Spectral Test Results 5-Min L2 Swath 250m and 1km
atmosphere NASA LAADS Level 2 active HDF-EOS
In plain English

What it measures. A cloud mask: for each pixel it states how confident the satellite is that it had a clear, unobstructed view of the ground versus seeing cloud, and it also flags likely shadows.

How it's made. Produced from the MODIS sensor on NASA's Terra satellite by running a series of visible and infrared tests on the measured light, at 250-meter and 1-kilometer detail.

How & where you'd use it. A foundational input used to decide which pixels are clear enough to use in other products like land, ocean, and atmosphere maps, rather than a final product on its own.

What's measured

ATMOSPHERE › CLOUDSATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD FREQUENCYATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD HEIGHT

Coverage & cadence

  • Time span2000-02-24 → ongoing
  • Measured byTerra (MODIS)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS
  • 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/Terra Cloud Mask and Spectral Test Results 5-Min L2 Swath 250m and 1km product consists of global cloud mask quality assurance and other ancillary parameters. The algorithm employs a series of visible and infrared threshold and consistency tests to specify confidence levels that an unobstructed view of the Earth's surface is observed. An indication of shadows affecting the scene is also provided. The 250-m cloud mask flags are based on the visible channel data only. Radiometrically accurate radiances are required, so holes in the cloud mask will appear wherever the input radiances are incomplete or of poor quality. The shortname for this Level-2 MODIS cloud mask product is MOD35_L2. The MOD35_L2 product files are stored in Hierarchical Data Format (HDF-EOS). This product consists of 9 parameters and each of these parameters are stored as a Scientific Data Set (SDS) within the HDF-EOS file. The Cloud Mask and Quality Assurance SDS's are stored at 1 kilometer pixel resolution. All other SDS's (those relating to time, geolocation, and viewing geometry) are stored at 5 kilometer pixel resolution. For more information about the MOD35_L2 product, visit the MODIS-Atmosphere site at: https://modis-atmos.gsfc.nasa.gov/products/cloud-mask

Get the data

mod35_l2_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MOD35_L2",
    version="6.1",
    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.