NLDAS Forcing Data L4 Hourly 0.125 x 0.125 degree V001 (NLDAS_FOR0125_H) at GES DISCEntry ID: GES_DISC_NLDAS_FOR0125_H_V001
Abstract: This data set contains the forcing data for Phase 1 of the North American Land Data Assimilation System (NLDAS-1). The data are in 1/8th degree grid spacing and range from 29 Sep 1996 to 31 Dec 2007. The temporal resolution is hourly. The file format is WMO GRIB-1.
The chief source of NLDAS-1 forcing is NCEP's Eta model-based Data Assimilation System (EDAS) [Rogers et al., 1995], a continuously ... cycled North American 4DDA system. It utilizes 3-hourly analysis-forecast cycles to derive atmospheric states by assimilating many types of observations, including station observations of surface pressure and screen-level atmospheric temperature, humidity, and U and V wind components. EDAS 3-hourly fields of the latter five variables plus surface downward shortwave and longwave radiation and total and convective precipitation are provided on a 40-km grid, and then interpolated spatially to the NLDAS grid and temporally to one hour. Last, to account for NLDAS versus EDAS surface-elevation differences, a terrain-height adjustment is applied to the air temperature and surface pressure using a standard lapse rate (6.5 K/km), then to specific humidity (keeping original relative humidity) and downward longwave radiation (for new air temperature, specific humidity). The details of the spatial interpolation, temporal disaggregation, and vertical adjustment are presented by Cosgrove et al. (2003).
GOES-based solar insolation (Pinker et al., 2003) provides the primary insolation forcing (shorwave down at the surface) for NLDAS-1. GOES insolation is not retrieved for zenith angles below 75 degrees and so is supplemented with EDAS insolation near the day/night terminator. Last from the GOES-based product suite, Photosynthetically Active Radiation (PAR) and surface brightness temperature fields are included in the NLDAS-1 forcing files.
NLDAS-1 precipitation forcing over CONUS is anchored to NCEP's 1/4th degree gauge-only daily precipitation analyses of Higgins et al. . In NLDAS-1, this daily analysis is interpolated to 1/8th degree, then temporally disaggregated to hourly values by applying hourly weights derived from hourly, 4-km, radar-based (WSR-88D) precipitation fields. The latter radar-based fields are used only to derive disaggregation weights and do not change the daily total precipitation. Last, convective precipitation is estimated by multiplying NLDAS-1 total precipitation by the ratio of EDAS convective to EDAS total precipitation. The Convective Available Potential Energy (CAPE) is the final variable in the forcing data set, also interpolated from EDAS.
The data set applies a user-defined parameter table to indicate the contents and parameter number. The GRIBTAB file (http://disc.sci.gsfc.nasa.gov/hydrology/grib_tabs/gribtab_NLDAS_FOR...) shows a list of parameters for this data set, along with their Product Definition Section (PDS) IDs and units.
For more information, please see the README Document at ftp://hydro1.sci.gsfc.nasa.gov/data/s4pa/NLDAS/README.NLDAS1.pdf.
Data Set Citation
Dataset Originator/Creator: Mitchell, K. E., et al., NCEP/EMC
Dataset Title: NLDAS Forcing Data L4 Hourly 0.125 x 0.125 degree
Dataset Series Name: NLDAS_FOR0125_H
Dataset Release Date: 08.01.2009
Dataset Release Place: Greenbelt, Maryland, USA
Dataset Publisher: Goddard Earth Sciences Data and Information Services Center (GES DISC)
Dataset Editor: David Mocko, NASA/GSFC/HSL
Data Presentation Form: Digital Science Data
Dataset DOI: 10.5067/H3CJY2R7C1RUOnline Resource: http://disc.sci.gsfc.nasa.gov/datacollection/NLDAS_FOR0125_H_V001.s...
Start Date: 1996-08-01Stop Date: 2007-12-31
Latitude Resolution: 0.125 degree
Longitude Resolution: 0.125 degree
Temporal Resolution: hourly
ATMOSPHERE > ATMOSPHERIC PRESSURE > SURFACE PRESSURE
ATMOSPHERE > ATMOSPHERIC WATER VAPOR > HUMIDITY
ATMOSPHERE > ATMOSPHERIC WINDS > CONVECTION
ATMOSPHERE > ATMOSPHERIC WINDS > SURFACE WINDS
ATMOSPHERE > ATMOSPHERIC RADIATION > LONGWAVE RADIATION
ATMOSPHERE > ATMOSPHERIC RADIATION > SHORTWAVE RADIATION
BIOSPHERE > VEGETATION > PHOTOSYNTHETICALLY ACTIVE RADIATION
SPECTRAL/ENGINEERING > INFRARED WAVELENGTHS > BRIGHTNESS TEMPERATURE
ATMOSPHERE > ATMOSPHERIC TEMPERATURE > SURFACE TEMPERATURE > AIR TEMPERATURE
ATMOSPHERE > PRECIPITATION > LIQUID PRECIPITATION > RAIN
ISO Topic Category
Quality The data are provisional and subject to change as model improvements are implemented and new input data sets become available.
Access Constraints None
Use Constraints None
Data Set Progress
Distribution Media: Online (HTTP)
Distribution Format: GRIB
Fees: No Fee
Role: TECHNICAL CONTACT
Email: gsfc-help-disc at lists.nasa.gov
Goddard Earth Sciences Data and Information Services Center Code 610.2 NASA Goddard Space Flight Center
Province or State: MD
Postal Code: 20771
Role: DIF AUTHOR
Email: Hualan.Rui at nasa.gov
Province or State: MD
Postal Code: 20771
Mitchell, K. E., et al. (2004), The multi-institution North American Land Data Assimilation System (NLDAS): Utilizing multiple GCIP products and partners in a continental distributed hydrological modeling system. J. Geophys. Res., 109, D07S90, doi:10.1029/2003JD003823.
Cosgrove, B. A., D. Lohmann, K. E. Mitchell, P. R. Houser, E. F. Wood, J. Schaake, A. Robock, C. Marshall, J. Sheffield, L. Luo, ... Q. Duan, R. T. Pinker, J. D. Tarpley, R. W. Higgins, and J. Meng (2003), Real-time and retrospective forcing in the North American Land Data Assimilation System (NLDAS) project, J. Geophys. Res., 108(D22), 8842, doi:10.1029/2002JD003118.
Higgins, R. W., W. Shi, E. Yarosh, and R. Joyce (2000), Improved United States precipitation quality control system and analysis, NCEP/Clim. Predict. Cent. Atlas 7, Clim. Predict. Cent., Camp Springs, Md.
Pinker, R. T., J. D. Tarpley, I. Laszlo, K. E. Mitchell, P. R. Houser, E. F. Wood, J. C. Schaake, A. Robock, D. Lohmann, B. A. Cosgrove, J. Sheffield, Q. Duan, L. Luo, and R. W. Higgins (2003), Surface radiation budgets in support of the GEWEX Continental-Scale International Project (GCIP) and the GEWEX Americas Prediction Project (GAPP), including the North American Land Data Assimilation System (NLDAS) project, J. Geophys. Res., 108(D22), 8844, doi:10.1029/2002JD003301.
Rogers, E., D. Deaven and G. J. DiMego, 1995: The regional analysis system for the operational "early" Eta model: original 80-km configuration and recent changes. Wea. Forecasting, 10, 810-825.
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2009-06-03
Last DIF Revision Date: 2016-01-20
Future DIF Review Date: 2015-04-30