Earth Data School
About
Full catalog/M2TUNXCSP
M2TUNXCSP·v5.12.4·dataset

Daily-cycle simulated satellite views for model checks (MERRA-2)

MERRA-2 tavgU_2d_csp_Nx: 2d,diurnal,Time-averaged,Single-Level,Assimilation,COSP Satellite Simulator 0.625 x 0.5 degree V5.12.4 (M2TUNXCSP) at GES DISC
atmosphere NASA GES_DISC Level 4 active
In plain English

What it measures. Simulated 'what a satellite would see' views of clouds — like total cloud cover and cloud particle sizes — averaged across the typical daily cycle, hour by hour.

How it's made. Generated by NASA's MERRA-2 reanalysis, a model that blends satellite-era observations into a consistent global record, run through a tool that mimics how cloud-watching satellites view the sky.

How & where you'd use it. Designed for comparing models against real satellite cloud observations on an apples-to-apples basis; a specialist tool for climate and cloud-feedback research rather than everyday use.

What's measured

ATMOSPHERE › ATMOSPHERIC RADIATION › ALBEDOATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD TOP PRESSUREATMOSPHERE › CLOUDS › CLOUD PROPERTIESATMOSPHERE › CLOUDS › CLOUD PROPERTIES › CLOUD FRACTIONATMOSPHERE › CLOUDS › CLOUD MICROPHYSICS › PARTICLE SIZE DISTRIBUTIONATMOSPHERE › CLOUDS › CLOUD MICROPHYSICS › CLOUD LIQUID WATER/ICEATMOSPHERE › CLOUDS › CLOUD MICROPHYSICS › CLOUD 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

M2TUNXCSP (or tavgU_2d_csp_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 parameters from CFMIP Observations Simulator Package(COSP), such as ISCCP total cloud area fraction, MODIS cloud fraction water (ice) mean, MODIS cloud fraction low (mid,high) mean, modis cloud particle size water (ice) mean. CFMIP is the abbreviation of Cloud Feedback Model Intercomparison Project. 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

m2tunxcsp_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="M2TUNXCSP",
    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.