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Full catalog/ML2H2O
ML2H2O·v006·dataset

Water vapor at different heights in the atmosphere (Aura)

MLS/Aura Level 2 Water Vapor (H2O) Mixing Ratio V006 (ML2H2O) at GES DISC
atmosphere NASA GES_DISC Level 2 active
In plain English

What it measures. Amounts of water vapor at many different heights in the atmosphere, from the lower atmosphere all the way up to very thin air, measured as profiles along the satellite's orbit. Coverage reaches nearly pole to pole.

How it's made. Derived from microwave signals recorded by the Microwave Limb Sounder on NASA's Aura satellite, mainly its 190 GHz radiometer, processed into vertical water-vapor profiles.

How & where you'd use it. Used to study how moisture is distributed and moves through the atmosphere at different altitudes, supporting atmospheric and climate research.

What's measured

ATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROFILES › WATER VAPOR MIXING RATIO PROFILES

Coverage & cadence

  • Time span2004-08-02 → ongoing
  • Measured byAura (MLS)
  • Processing levelLevel 2
  • Spatial extent-180, -82, 180, 82
  • 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

ML2H2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for water vapor derived from radiances measured primarily by the 190 GHz radiometer. The data version is 6.0. Spatial coverage is near-global (-82 degrees to +82 degrees latitude), with each profile spaced 1.5 degrees or ~165 km along the orbit track (roughly 15 orbits per day). The recommended useful vertical range is between 316 and 0.001 hPa, and the vertical resolution is about 1.5 km at 316 hPa increasing to 3.5 km to 4.64 hPa, and degrades to 15 km above 0.1 hPa. Users of the ML2H2O data product should read section 3.10 of the EOS MLS Level 2 Version 6 Quality Document for more information. The data are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5), which is based on the version 5 Hierarchical Data Format, or HDF-5. Each file contains two swath objects (profile and column data), each with a set of data and geolocation fields, swath attributes, and metadata.

Get the data

ml2h2o_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="ML2H2O",
    version="006",
    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.