Earth Data School
About
Full catalog/ML3DBHOCL
ML3DBHOCL·v005·dataset

Chlorine acid (HOCl) in the stratosphere (Aura, daily)

MLS/Aura Level 3 Daily Binned Hypochlorous Acid (HOCl) Mixing Ratio on Assorted Grids V005 (ML3DBHOCL) at GES DISC
atmosphere NASA GES_DISC Level 3 active
In plain English

What it measures. Daily amounts of hypochlorous acid, a chlorine compound, at different heights in the stratosphere, reported across near-global latitudes.

How it's made. Derived from microwave signals measured by the MLS instrument on NASA's Aura satellite, then binned onto various vertical grids.

How & where you'd use it. Helps scientists study the chlorine chemistry tied to ozone loss in the upper atmosphere.

What's measured

ATMOSPHERE › ATMOSPHERIC CHEMISTRY › HALOCARBONS AND HALOGENS › HYPOCHLOROUS ACID

Coverage & cadence

  • Time span2004-08-02 → ongoing
  • Measured byAura (MLS)
  • Processing levelLevel 3
  • 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

ML3DBHOCL is the EOS Aura Microwave Limb Sounder (MLS) daily binned on various vertical grids product for hypochlorous acid (HOCl) derived from radiances measured primarily by the 640 GHz radiometer. The data version is 5.1. Spatial coverage is near-global (-82 to +82 degrees latitude) at a spatial resolution of 4 degrees latitude by 5 degrees longitude. The recommended useful vertical range is from 10 to 2.15 hPa, and the vertical resolution is about 6 km. Users of the ML3DBOHCL data product should read chapter 4 and section 3.14 of the EOS MLS Level 2 Version 5 Quality Document for more information. The data files are archived in the netCDF4 format, which is also compatible with HDF5 readers and tools. Each file contains six group objects: lat-lon map vs pressure, lat vs pressure zonal mean, lat-lon map vs "potential temperature", lat vs "potential temperature" zonal mean, "equivalent latitude" vs "potential temperature" zonal mean, and vortex average vs "potential temperature". These are further subdivided into groups with all valid, ascending orbit, descending orbit, daytime (SZA < 90), and nighttime (SZA > 110) profiles. Each group has a set of data (average, min, max, std dev, rms) and geolocation fields, grid attributes, and metadata.

Get the data

ml3dbhocl_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="ML3DBHOCL",
    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.