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Full catalog/ML2HCL
ML2HCL·v005·dataset

Hydrogen chloride high in the atmosphere (Aura)

MLS/Aura Level 2 Hydrogen Chloride (HCl) Mixing Ratio V005 (ML2HCL) at GES DISC
atmosphere NASA GES_DISC Level 2 active
In plain English

What it measures. Measures how much hydrogen chloride is present at different heights in the upper atmosphere, given as profiles along the satellite's orbit covering most of the globe. Hydrogen chloride is important to the chemistry that affects the ozone layer.

How it's made. Derived from microwave radiances measured by the Microwave Limb Sounder on NASA's Aura satellite, processed into vertical profiles (Level 2).

How & where you'd use it. Used by atmospheric scientists to study chlorine chemistry and ozone-layer processes in the stratosphere; primarily a research product.

What's measured

ATMOSPHERE › ATMOSPHERIC CHEMISTRY › HALOCARBONS AND HALOGENS › HYDROGEN CHLORIDE

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

ML2HCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hydrogen chloride derived from radiances measured primarily by the 640 GHz radiometer. The data version is 5.0. 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 from 100 to 0.316 hPa, and the vertical resolution is between 3 and 6 km. Users of the ML2HCL data product should read section 3.10 of the EOS MLS Level 2 Version 5 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

ml2hcl_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="ML2HCL",
    version="005",
    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.