Cloud amounts by altitude, daily cycle (model)
What it measures. How cloud properties vary across a typical day and at different altitudes, including how much of the sky is cloudy and how much cloud water or ice is present at each level. These are model results, not direct satellite snapshots.
How it's made. Produced by NASA's MERRA-2 reanalysis, which blends decades of observations into a consistent physics-based model, here as monthly averages of the daily cycle on pressure levels.
How & where you'd use it. Used in climate and weather research to study how clouds behave through the day and across altitudes, and as consistent long-term input for other studies.
What's measured
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
M2TUNPCLD (or tavgU_3d_cld_Np) is a 3-dimensional monthly diurnal means data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilations of cloud diagnostics on 42 the pressure levels, such as updraft areal fraction, cloud fraction for radiation, in-cloud cloud liquid (or ice) for radiation, and mass fraction of cloud liquid (or ice) water. The information on the pressure levels can be found in the section 4.2 of the MERRA-2 File Specification document. This data collection is the monthly mean of data fields for each 3-hour and time-stamped at the central time starting from 01:30 UTC, e.g.: 01:30, 04:30, … , 22:30 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
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="M2TUNPCLD",
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_DISCBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package. Official links
- How to read and plot the data. VIEW RELATED INFORMATION
- Access the data via HTTPS. GET DATA
- Use the Earthdata Search to find and retrieve data sets across multiple data centers. GET DATA
- Access the data via the OPeNDAP protocol. USE SERVICE API
- MERRA-2 File Specification Document VIEW RELATED INFORMATION
- README Document VIEW RELATED INFORMATION
- MERRA-2 Data Access – Quick Start Guide VIEW RELATED INFORMATION
- Records of MERRA-2 Data Reprocessing and Service Changes VIEW RELATED INFORMATION