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Description

M2T3NXGLC (or tavg3_2d_glc_Nx) is a 2-dimensional 3-hourly time-averaged 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. The data field is available every three hour 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).

Version Description

The GEOS-5 model version used for processing MERRA-2

Product Summary

Platforms
MERRA-2
Instruments
NOT APPLICABLE
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
0.625 Decimal Degrees x 0.5 Decimal Degrees
Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1980-01-01 to Present
Data Partner
Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Terrestrial Information Systems Laboratory, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/GESDI
Concept ID
C1276812864-GES_DISC
Data State
ACTIVE
Number of Files/Granules
16923
Processing Level
4
Published
Updated
Science Keywords
Albedo ,
Snow Depth ,
Snow Depth ,
Glacier Runoff ,
Glacier Runoff ,
Snow Cover

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Global Modeling and Assimilation Office, & Pawson, S. (2015). MERRA-2 tavg3_2d_glc_Nx: 2d,3-Hourly,Time-Averaged,Single-Level,Assimilation,Land Ice Surface Diagnostics V5.12.4 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/9ETB4TT5J6US Date Accessed: 2026-06-03

Documents

Publications Citing This Dataset

Filters
Title Year Author Topic
Simulations of firn processes over the Greenland and Antarctic ice sheets: 19802021 Medley, Brooke, Neumann, Thomas A., Zwally, H. Jay, Smith, Benjamin E., Stevens, C. Max Heat Flux, Air Temperature, Skin Temperature, Specific Humidity, Water Vapor, Precipitation Rate, Snow/Ice, Evaporation, Latent Heat Flux, Latent Heat Flux, Sensible Heat Flux, Diffusion, Surface Winds, Wind Speed, U/V Wind Components, Wind Stress, Wind Stress, Surface Roughness, Planetary Boundary Layer Height, Ice Fraction, Geopotential Height, Altitude, Surface Temperature, Upper Air Temperature, Dew Point Temperature, Cloud Top Temperature, Atmospheric Winds, Surface Winds, Upper Level Winds, U/V Wind Components, Vertical Wind Velocity/Speed, Atmospheric Pressure, Sea Level Pressure, Cloud Top Pressure, Sea Level Pressure, Surface Pressure, Total Precipitable Water, Cloud Liquid Water/Ice, Atmospheric Water Vapor, Atmospheric Ozone, Oxygen Compounds, Boundary Layer Winds, Total Ozone, Albedo, Snow Depth, Snow Depth, Glacier Runoff, Glacier Runoff, Snow Cover
Temporal variability in snow accumulation and density at Summit Camp, Greenland ice sheet Howat, Ian M. Albedo, Snow Depth, Snow Depth, Glacier Runoff, Glacier Runoff, Snow Cover
Surface meltwater runoff routing through a coupled supraglacial-proglacial drainage system, Inglefield Land, northwest Greenland Li, Ya, Yang, Kang, Gao, Shuai, Smith, Laurence C., Fettweis, Xavier, Li, Manchun Longwave Radiation, Shortwave Radiation, Soil Heat Budget, Soil Heat Budget, Soil Temperature, Soil Temperature, Soil Infiltration, Soil Infiltration, Soil Moisture/Water Content, Surface Soil Moisture, Root Zone Soil Moisture, Soil Moisture/Water Content, Evaporation, Surface Water, Runoff Rate, Average Flow, Average Flow, Precipitation, Snow/Ice, Snow Depth, Snow Melt, Snow/Ice Temperature, Leaf Area Index (LAI), Leaf Area Index (LAI), Albedo, Snow Depth, Snow Depth, Glacier Runoff, Glacier Runoff, Snow Cover
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Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
ASNOW_GL ASNOW_GL 1 float32 999999986991104 N/A 1 0
lat lat degrees_north float64 N/A N/A N/A N/A
lon lon degrees_east float64 N/A N/A N/A N/A
RUNOFF RUNOFF kg m-2 s-1 float32 999999986991104 N/A 1 0
SNICEALB SNICEALB 1 float32 999999986991104 N/A 1 0
SNOMAS_GL SNOMAS_GL kg m-2 float32 999999986991104 N/A 1 0
SNOWDP_GL SNOWDP_GL m float32 999999986991104 N/A 1 0
time time minutes since 2025-01-01 01:30:00 int32 N/A N/A N/A N/A
WESNEXT WESNEXT kg m-2 s-1 float32 999999986991104 N/A 1 0
WESNSC WESNSC kg m-2 s-1 float32 999999986991104 N/A 1 0
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