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Full catalog/ML2HOCL
ML2HOCL·v005·dataset

Hypochlorous acid in the upper atmosphere

MLS/Aura Level 2 Hypochlorous Acid (HOCl) Mixing Ratio V005 (ML2HOCL) at GES DISC
atmosphere NASA GES_DISC Level 2 active
In plain English

What it measures. Measures hypochlorous acid, a chlorine-containing gas, and how much of it is present at different heights high up in the atmosphere, with coverage spanning most of the globe.

How it's made. Derived from microwave energy recorded by the MLS instrument on the Aura satellite, turned into gas amounts along each orbit track.

How & where you'd use it. Mainly for atmospheric chemistry research, especially studies of the chlorine chemistry involved in the breakdown of the protective ozone layer.

What's measured

ATMOSPHERE › ATMOSPHERIC CHEMISTRY › HALOCARBONS AND HALOGENS › HYPOCHLOROUS ACID

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

ML2HOCL is the EOS Aura Microwave Limb Sounder (MLS) standard product for hypochlorous acid 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 10 to 2.15 hPa, and the vertical resolution is about 6 km. Users of the ML2OHCL data product should read section 3.14 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

ml2hocl_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="ML2HOCL",
    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.