Earth Data School
About
Full catalog/MYD35_L2
MYD35_L2·v6.1·dataset

Where the clouds are (Aqua, cloud mask)

MODIS/Aqua 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. Flags where clouds are in each satellite scene, giving a confidence level that the view of the ground is clear or blocked, plus hints about shadows. In short, it answers where the clouds are.

How it's made. Created from the MODIS instrument on the Aqua satellite by running a series of visible and infrared tests on each pixel to judge clear versus cloudy.

How & where you'd use it. An essential screening tool used to throw out cloudy pixels when making clear-sky products of the land, ocean, and atmosphere; it is mostly used as an input by other products.

What's measured

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

Coverage & cadence

  • Time span2002-07-04 → ongoing
  • Measured byAqua (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/Aqua 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 MYD35_L2. The MYD35_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 MYD35_L2 product, visit the MODIS-Atmosphere site at: https://modis-atmos.gsfc.nasa.gov/products/cloud-mask

Get the data

myd35_l2_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MYD35_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.