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Full catalog/M2TUNXRAD
M2TUNXRAD·v5.12.4·dataset

Modeled daily sunlight and heat balance (MERRA-2)

MERRA-2 tavgU_2d_rad_Nx: 2d,diurnal,Time-Averaged,Single-Level,Assimilation,Radiation Diagnostics 0.625 x 0.5 degree V5.12.4 (M2TUNXRAD) at GES DISC
atmosphere NASA GES_DISC Level 4 active
In plain English

What it measures. Monthly averages of the sun-and-heat balance at the surface and top of the atmosphere, including how much sunlight reaches the ground, how reflective the surface is, cloud cover, and the heat radiating back out to space, broken down by hour of the day.

How it's made. Comes from MERRA-2, a NASA computer reanalysis that blends decades of satellite-era observations into a physics model to recreate a consistent record from 1980 to the present.

How & where you'd use it. Used to study Earth's energy budget, cloud and radiation patterns, and long-term climate, with the hourly breakdown helping capture daily cycles.

What's measured

ATMOSPHERE › ATMOSPHERIC RADIATIONATMOSPHERE › ATMOSPHERIC RADIATION › LONGWAVE RADIATIONATMOSPHERE › ATMOSPHERIC RADIATION › SHORTWAVE RADIATIONATMOSPHERE › ATMOSPHERIC RADIATION › RADIATIVE FLUXATMOSPHERE › ATMOSPHERIC RADIATION › RADIATIVE FORCINGLAND SURFACE › SURFACE RADIATIVE PROPERTIESLAND SURFACE › SURFACE RADIATIVE PROPERTIES › ALBEDOLAND SURFACE › SURFACE RADIATIVE PROPERTIES › EMISSIVITYATMOSPHERE › CLOUDS › CLOUD PROPERTIESATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD FRACTIONATMOSPHERE › CLOUDS › CLOUD MICROPHYSICS › CLOUD OPTICAL DEPTH/THICKNESSATMOSPHERE › ATMOSPHERIC TEMPERATURE › SURFACE TEMPERATURE › SKIN TEMPERATURELAND SURFACE › SURFACE THERMAL PROPERTIES › SKIN TEMPERATUREOCEANS › OCEAN TEMPERATURE › SEA SURFACE TEMPERATURE › SEA SURFACE SKIN TEMPERATURE

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

M2TUNXRAD (or tavgU_2d_rad_Nx) is a time-averaged 2-dimensional monthly diurnal means data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of radiation diagnostics, such as surface albedo, cloud area fraction, in cloud optical thickness, surface incoming shortwave flux (i.e. solar radiation), surface net downward shortwave flux, and upwelling longwave flux at toa (top of atmosphere) (i.e. outgoing longwave radiation (OLR) at toa). This data collection is the monthly mean of data fields for each hour and time-stamped with the central time of an hour starting from 00:30 UTC, e.g.: 00:30, 01:30, … , 23:30 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

m2tunxrad_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="M2TUNXRAD",
    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.