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Full catalog/M2TUNXGLC
M2TUNXGLC·v5.12.4·dataset

How ice-sheet surfaces change through the day (MERRA-2)

MERRA-2 tavgU_2d_glc_Nx: 2d,diurnal,Time-Averaged,Single-Level,Assimilation,Land Ice Surface Diagnostics 0.625 x 0.5 degree V5.12.4 (M2TUNXGLC) at GES DISC
cryosphere NASA GES_DISC Level 4 active
In plain English

What it measures. Shows how conditions on glacier and ice-sheet surfaces vary over the course of a typical day — things like snow-covered area, snow mass, and snow depth on icy ground — averaged by month.

How it's made. Comes from MERRA-2, a NASA reanalysis that blends decades of satellite observations into a consistent computer model of the global atmosphere and surface, gridded at about half a degree.

How & where you'd use it. Useful for studying snow and ice behavior on glaciated surfaces and for climate and Earth-system research that needs a steady, gap-free record back to 1980.

What's measured

CRYOSPHERE › SNOW/ICE › ALBEDOCRYOSPHERE › SNOW/ICE › SNOW DEPTHCRYOSPHERE › SEA ICE › SNOW DEPTHCRYOSPHERE › GLACIERS/ICE SHEETS › GLACIERS › GLACIER RUNOFFTERRESTRIAL HYDROSPHERE › GLACIERS/ICE SHEETS › GLACIERS › GLACIER RUNOFFCRYOSPHERE › SNOW/ICE › SNOW COVER

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

  • Measure sea ice, snow cover and glaciers
  • Watch ice-sheet elevation change
  • Track freeze/thaw and permafrost
Official description

M2TUNXGLC (or tavgU_2d_glc_Nx) is a 2-dimensional monthly diurnal means data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilated land ice surface diagnostics at the single levels, such as fractional area of glaciated surface snow cover, snow mass over glaciated surface, snow depth over glaciated surface, and total snow mass residual due to densification. 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

m2tunxglc_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="M2TUNXGLC",
    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.