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Description

This data set contains the monthly secondary forcing data "File B" 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 format).

The NLDAS-2 monthly secondary forcing data were generated from the NLDAS-2 hourly secondary forcing data, as monthly accumulation for precipitation and convective precipitation and monthly average for other variables. 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 B" is the secondary (optional) forcing file and contains ten 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

Geographic Region
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
C1887991357-GES_DISC
Data State
ACTIVE
Number of Files/Granules
563
Processing Level
4
Published
Updated
Science Keywords
Geopotential Height ,
Surface Pressure ,
Shortwave Radiation ,
Surface Temperature ,
Humidity ,
Convection ,
Surface Winds ,
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 Secondary 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/10.5067/7EF175EAK5NA Date Accessed: 2025-12-14

Documents

READ-ME

PROCESSING HISTORY

GENERAL DOCUMENTATION

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
ACond ACond m s-1 float32 -9999 N/A 1
CRainf CRainf kg m-2 float32 -9999 N/A 1
lat lat degrees_north float32 -9999 N/A 1
lon lon degrees_east float32 -9999 N/A 1
PhiS PhiS gpm float32 -9999 N/A 1
PSurf PSurf Pa float32 -9999 N/A 1
Qair Qair kg kg-1 float32 -9999 N/A 1
Rainf Rainf kg m-2 float32 -9999 N/A 1
SWdown SWdown W m-2 float32 -9999 N/A 1
Tair Tair K float32 -9999 N/A 1
time time hours since 1979-01-01 00:00:00 float64 N/A N/A N/A
time_bnds time_bnds N/A float64 N/A N/A N/A
Wind_E Wind_E m s-1 float32 -9999 N/A 1
Wind_N Wind_N m s-1 float32 -9999 N/A 1
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