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Full catalog/M2I3NXGAS
M2I3NXGAS·v5.12.4·dataset

Haze and dust in the air, every 3 hours (MERRA-2)

MERRA-2 inst3_2d_gas_Nx: 2d,3-Hourly,Instantaneous,Single-Level,Assimilation,Aerosol Optical Depth Analysis 0.625 x 0.5 degree V5.12.4 (M2I3NXGAS) at GES DISC
atmosphere NASA GES_DISC Level 4 active
In plain English

What it measures. How much haze and dust are in the air worldwide, given as aerosol optical depth (a measure of how much airborne particles dim the view), reported every three hours on a roughly half-degree grid.

How it's made. Comes from MERRA-2, NASA's atmospheric reanalysis that blends satellite observations into a model; this collection holds the aerosol optical depth analysis and covers 1980 to the present.

How & where you'd use it. Useful for studying air pollution, dust events, and haze over long periods and across the whole globe, and for connecting aerosols to weather and climate. The steady three-hour cadence suits time-series analysis.

What's measured

ATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESS

Coverage & cadence

  • Time span1980-01-01 → ongoing
  • Measured byMERRA-2 (NOT APPLICABLE)
  • Processing levelLevel 4
  • Spatial extent-180, -90, 180, 90
  • 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

M2I3NXGAS (or inst3_3d_gas_Nx) is an instantaneous 2-dimensional 3-hourly data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilation of aerosol optical depth analysis and aerosol optical depth analysis increment. The data field is available every three hour starting from 00:00 UTC, e.g.: 00:00, 03:00, … , 21:00 UTC. MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by NASA Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers the period of 1980-present with the latency of ~3 weeks after the end of a month. Data Reprocessing: Please check “Records of MERRA-2 Data Reprocessing and Service Changes” linked from the “Documentation” tab on this page. Note that a reprocessed data filename is different from the original file. MERRA-2 Mailing List: Sign up to receive information on reprocessing of data, changing of tools and services, as well as data announcements from GMAO. Contact the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov) to be added to the list. Questions: If you have a question, please read "MERRA-2 File Specification Document", “MERRA-2 Data Access – Quick Start Guide”, and FAQs linked from the ”Documentation” tab on this page. If that does not answer your question, you may post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).

Get the data

m2i3nxgas_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="M2I3NXGAS",
    version="5.12.4",
    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.