Earth Data School
About
Full catalog/M2IMNXASM
M2IMNXASM·v5.12.4·dataset

Modeled monthly weather snapshot (MERRA-2, 0.5 deg)

MERRA-2 instM_2d_asm_Nx: 2d,Monthly mean,Single-Level,Assimilation,Single-Level Diagnostics 0.625 x 0.5 degree V5.12.4 (M2IMNXASM) at GES DISC
atmosphere NASA GES_DISC Level 4 active
In plain English

What it measures. A monthly average snapshot of near-surface weather worldwide, including things like air temperature at 2 and 10 meters, winds at several heights, surface pressure, and total water vapor in the air. These are modeled estimates.

How it's made. Produced by NASA's MERRA-2 atmospheric reanalysis, which runs the GEOS model and blends in satellite-era observations to reconstruct conditions from 1980 to the present.

How & where you'd use it. Useful for studying climate trends, regional weather patterns, and as a consistent long-term backdrop for many kinds of environmental research.

What's measured

ATMOSPHERE › ATMOSPHERIC TEMPERATURE › SURFACE TEMPERATURELAND SURFACE › SURFACE THERMAL PROPERTIES › SKIN TEMPERATUREATMOSPHERE › ATMOSPHERIC TEMPERATURE › UPPER AIR TEMPERATUREATMOSPHERE › ATMOSPHERIC TEMPERATURE › SURFACE TEMPERATURE › AIR TEMPERATUREATMOSPHERE › ATMOSPHERIC WINDSATMOSPHERE › ATMOSPHERIC WINDS › SURFACE WINDSATMOSPHERE › ATMOSPHERIC WINDS › SURFACE WINDS › U/V WIND COMPONENTSATMOSPHERE › ATMOSPHERIC PRESSUREATMOSPHERE › ATMOSPHERIC PRESSURE › SEA LEVEL PRESSUREATMOSPHERE › ATMOSPHERIC PRESSURE › SURFACE PRESSUREATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORS › HUMIDITY › SPECIFIC HUMIDITYATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORS › TOTAL PRECIPITABLE WATERATMOSPHERE › CLOUDS › CLOUD MICROPHYSICS › CLOUD LIQUID WATER/ICEATMOSPHERE › ATMOSPHERIC WATER VAPOR

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

M2IMNXASM (or instM_2d_asm_Nx) is an instantaneous 2-dimensional monthly mean data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilations of meteorological diagnostic parameters at the single levels, such as temperature at 2-meter and 10-meter; wind components at 2-meter, 10-meter, and 50-meter; surface pressure, and total precipitable water. The collection also includes variance of certain parameters. 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

m2imnxasm_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="M2IMNXASM",
    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.