Skip to main content

Description

M2TCNXLTM (or tavgC_2d_ltm_Nx) is a 2-dimensional monthly data collection for climatological long term mean and standard deviation representing the interannual variability on a monthly timescale, derived from monthly Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) datasets. V2 of this data collection is calculated with data from January 1991 to December 2020. In contrast, V1, the original version, is computed with data from an earlier 30-year time of 1981-2010.

This collection consists of meteorological diagnostics, such as air temperature (maximum, mean, and minimum at 2-meter), wind components at different vertical levels (2-meter, 10-meter, 50-meter, 850 hPa, 500hPa, and 250 hPa), sea level pressure, surface pressure, and total precipitation, evaporation, and total precipitable water vapor.

MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by the 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 a latency of ~3 weeks after the end of the previous 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 filename.

MERRA-2 Mailing List: Sign up to receive information on reprocessing of data, changes to 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 the "MERRA-2 File Specification Document'', “MERRA-2 Data Access – Quick Start Guide”, and FAQs linked from the ”Documentation” tab on this page for more information. If these documents do 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

Version 1 climate Indices derived from 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
1981-01-01 to 2010-12-31
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
C1949650995-GES_DISC
Data State
COMPLETE
Number of Files/Granules
12
Processing Level
4
Published
Updated
Science Keywords
Air Temperature ,
Precipitation Rate

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

Collow, A. (2020). MERRA-2 tavgC_2d_ltm_Nx: 2d, Single-Level, Long Term Mean Diagnostics V1 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/HWSZE7YK7L81 Date Accessed: 2026-05-04

Documents

Publications Citing This Dataset

Filters
Title Year Author Topic
Seasonal Variability in the Mechanisms Behind the 2020 Siberian Heatwaves Collow, Allison B. Marquardt, Thomas, Natalie P., Bosilovich, Michael G., Lim, Young-Kwon, Schubert, Siegfried D., Koster, Randal D. Geopotential Height, Altitude, Surface Temperature, Upper Air Temperature, Dew Point Temperature, Air Temperature, Cloud Top Temperature, Atmospheric Winds, Surface Winds, U/V Wind Components, Upper Level Winds, U/V Wind Components, Vertical Wind Velocity/Speed, Atmospheric Pressure, Sea Level Pressure, Cloud Top Pressure, Sea Level Pressure, Surface Pressure, Specific Humidity, Total Precipitable Water, Cloud Liquid Water/Ice, Atmospheric Water Vapor, Atmospheric Ozone, Oxygen Compounds, Boundary Layer Winds, Skin Temperature, Precipitation Rate, 24 Hour Maximum Temperature, 24 Hour Minimum Temperature, Heat Flux, Water Vapor, Snow/Ice, Evaporation, Latent Heat Flux, Latent Heat Flux, Sensible Heat Flux, Diffusion, Surface Winds, Wind Speed, Wind Stress, Wind Stress, Surface Roughness, Planetary Boundary Layer Height, Ice Fraction, 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, Surface Water, Runoff Rate, Average Flow, Average Flow, Precipitation, Snow Depth, Snow Melt, Snow/Ice Temperature, Leaf Area Index (LAI), Leaf Area Index (LAI), Extreme Drought, Heat/Cold Wave Frequency/Intensity, Extreme Precipitation
You're viewing 1 of 1

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
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
PRECTOT PRECTOT kg m-2 s-1 float32 -9999 N/A N/A N/A
std_PRECTOT std_PRECTOT kg m-2 s-1 float32 -9999 N/A N/A N/A
std_T2MMAX std_T2MMAX K float32 -9999 N/A N/A N/A
std_T2MMEAN std_T2MMEAN K float32 -9999 N/A N/A N/A
std_T2MMIN std_T2MMIN K float32 -9999 N/A N/A N/A
T2MMAX T2MMAX K float32 -9999 N/A N/A N/A
T2MMEAN T2MMEAN K float32 -9999 N/A N/A N/A
T2MMIN T2MMIN K float32 -9999 N/A N/A N/A
time time minutes since 1981-12-01 00:30:00 float64 N/A N/A N/A N/A
You're viewing 11 of 11