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Description

This data product contains the monthly primary forcing data "File A" for Phase 2 of the North American Land Data Assimilation System (NLDAS-2). The data are in 1/8th degree grid spacing and range from Jan 1979 to the present. The temporal resolution is monthly. The file format is netCDF (converted from the GRIB data files).

The NLDAS-2 monthly primary forcing data were generated from the NLDAS-2 hourly primary forcing data, as monthly accumulation for total precipitation, convective precipitation, and potential evaporation, and monthly average for other variables. The convective precipitation monthly total is the hourly convective fraction multiplied by the hourly precipitation (both from the NLDAS-2 "File A" files), and then summed over all hours of the month. Monthly period of each month is from 00Z at start of the month to 23:59Z at end of the month. The one exception to this is the first month (Jan. 1979) that starts from 00Z 02 Jan 1979, except for the monthly accumulated precipitation and convective precipitation that both start from 12Z 01 Jan 1979.

The monthly land surface forcing fields for NLDAS-2 are grouped into two files, "File A" and "File B". "File A" is the primary (default) forcing file and contains eleven meteorological forcing fields. Details about the generation of the NLDAS-2.0 forcing datasets can be found in Xia et al. (2012).

Product Summary

Platforms
Forcing-LSM
Instruments
NOT APPLICABLE
Spatial Extent

N: 53 S: 25 E: -67 W: -125

Location
NORTH AMERICA
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1979-01-01 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
C1887583680-GES_DISC
Data State
ACTIVE
Number of Files/Granules
567
Processing Level
4
Published
Updated
Science Keywords
Surface Pressure ,
Longwave Radiation ,
Shortwave Radiation ,
Surface Temperature ,
Humidity ,
Evaporation ,
Surface Winds ,
Convection ,
Rain ,
Land Surface Temperature

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

NLDAS Project. (2020). NLDAS Primary Forcing Data L4 Monthly 0.125 x 0.125 degree V2.0 [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/2DPKB5B5N14O Date Accessed: 2026-04-10

Documents

READ-ME

PROCESSING HISTORY

GENERAL DOCUMENTATION

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
CAPE CAPE J kg-1 float32 -9999 N/A 1 0
CRainf CRainf kg m-2 float32 -9999 N/A 1 0
lat lat degrees_north float32 -9999 N/A 1 0
lon lon degrees_east float32 -9999 N/A 1 0
LWdown LWdown W m-2 float32 -9999 N/A 1 0
PotEvap PotEvap kg m-2 float32 -9999 N/A 1 0
PSurf PSurf Pa float32 -9999 N/A 1 0
Qair Qair kg kg-1 float32 -9999 N/A 1 0
Rainf Rainf kg m-2 float32 -9999 N/A 1 0
SWdown SWdown W m-2 float32 -9999 N/A 1 0
Tair Tair K float32 -9999 N/A 1 0
time time hours since 1979-01-01 00:00:00 float64 N/A N/A N/A N/A
time_bnds time_bnds N/A float64 N/A N/A N/A N/A
Wind_E Wind_E m s-1 float32 -9999 N/A 1 0
Wind_N Wind_N m s-1 float32 -9999 N/A 1 0
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