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Full catalog/ML3DBHCN
ML3DBHCN·v005·dataset

Hydrogen cyanide in the upper atmosphere (Aura, daily)

MLS/Aura Level 3 Daily Binned Hydrogen Cyanide (HCN) Mixing Ratio on Assorted Grids V005 (ML3DBHCN) at GES DISC
atmosphere NASA GES_DISC Level 3 active
In plain English

What it measures. How much hydrogen cyanide is in the upper atmosphere, summarized day by day across the globe at different altitudes.

How it's made. Comes from the Microwave Limb Sounder on NASA's Aura satellite, which detects the gas mainly through its 190 GHz radio signal, then bins the readings onto map grids.

How & where you'd use it. Hydrogen cyanide is largely produced by biomass burning, so this helps scientists trace how smoke and fire emissions travel high into the atmosphere.

What's measured

ATMOSPHERE › ATMOSPHERIC CHEMISTRY › CARBON AND HYDROCARBON COMPOUNDS › HYDROGEN CYANIDE

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

ML3DBHCN is the EOS Aura Microwave Limb Sounder (MLS) daily binned on various vertical grids product for hydrogen cyanide (HCN) derived from radiances measured primarily by the 190 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 21.5 to 0.1 hPa, and the vertical resolution is between 8 and 12 km. Users of the ML3DBHCN data product should read chapter 4 and section 3.11 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". Each group has a set of data (average, min, max, std dev, rms) and geolocation fields, grid attributes, and metadata.

Get the data

ml3dbhcn_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="ML3DBHCN",
    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.