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Full catalog/OMCLDO2
OMCLDO2·v004·dataset

Cloud height and how much sky clouds cover (Aura)

OMI/Aura Cloud Pressure and Fraction (O2-O2 Absorption) 1-Orbit L2 Swath 13x24km V004 (OMCLDO2) at GES DISC
atmosphere NASA GES_DISC Level 2 active
In plain English

What it measures. For each satellite footprint, the height (pressure) of clouds and how much of the sky is covered by cloud, plus related atmospheric details.

How it's made. Derived from the Ozone Monitoring Instrument on NASA's Aura satellite using how oxygen absorbs light near 477 nm; each file covers the daylit part of one orbit at about 13x24 km resolution.

How & where you'd use it. Used to characterize clouds, which is essential for correctly interpreting other measurements of ozone and air pollution from the same instrument.

What's measured

ATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD FRACTIONATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD TOP PRESSURE

Coverage & cadence

  • Time span2004-10-01 → ongoing
  • Measured byAura (OMI)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • 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 Level-2 Aura Ozone Monitoring Instrument (OMI) Cloud Pressure and Fraction (O2-O2 Absorption) Product (OMCLDO2) version 4 is now available from NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) for public access. The data was re-processed in December 2022 using collection 4 Level 1b data and the OMCLDO2 processor version 4.0.0. Since then, this version of the product is also being produced in the forward stream. This version of the product was publicly released in March 2026. OMI provides two cloud products based on two different algorithms, the Rotational Raman Scattering method, and O2-O2 absorption method using the DOAS technique. This level-2 global cloud product, with a pixel resolution of 13x24 km2 at nadir, is based on the spectral fitting of O2-O2 absorption band at 477 nm using DOAS technique. This product contains cloud pressure, cloud fraction, slant column O2-O2, ozone, ring coefficients, uncertainties in derived parameters, terrain and geolocation information, solar and satellite viewing angles, and quality flags. The lead scientist for this product is Dr. Pepijn Veefkind. The OMCLDO2 files are stored in netCDF 4 format. Each file contains data from the day lit portion of an orbit (~53 minutes). There are approximately 14 orbits per day. The maximum file size for the OMCLDO2 data product is about 13 Mbytes.

Get the data

omcldo2_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="OMCLDO2",
    version="004",
    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 GES_DISC
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.