NLDAS2

Description: The Land Data Assimilation System (LDAS) combines multiple sources of observations (such as precipitation gauge data, satellite data, and radar precipitation measurements) to produce estimates of climatological properties at or near the Earth's surface. This dataset is the primary (default) forcing file (File A) for Phase 2 of the North American Land Data Assimilation System (NLDAS-2). The data are in 1/8th-degree grid spacing; the temporal resolution is hourly. 

Organization: NASA

Spatial resolution: ~12-km (0.75-deg x 0.75-deg)

Time Span: 1979-01-02 to Present (updated every 3-5 days)

Variables:

• Minimum/Maximum/Mean daily air temperature at 2 meters above the surface 
• Total daily Precipitation
• Mean daily surface downward longwave radiation (W/m^2)
  • Reflects average over all hours of the day.
  • To go from Watts/m^2 to MJ/(m^2day) you need to multiply the number of sec in a day: watts/meter² x 86400 s/day x 1 MJ/10^6 J = MJ/(meter²*day).
• Mean daily surface downward shortwave radiation (W/m^2)
  • Reflects average over all hours of the day.
  • To go from Watts/m^2 to MJ/(m^2day) you need to multiply the number of sec in a day: watts/meter² x 86400 s/day x 1 MJ/10^6 J = MJ/(meter²*day).
• Daily grass reference ET
• Daily alfalfa reference ET
• Specific Humidity at 2 meters above the surface
• Wind Speed
• Mean daily surface pressure 

Website: NLDAS2 Model Website

Google Earth Engine: 

• Though, NLDAS2 is publicly available on Google Earth Engine, Climate Engine accesses this data as a private GEE asset.

Terms of Use:

• Distribution of data from the Goddard Earth Sciences Data and Information Services Center (GES DISC) is funded by NASA's Science Mission Directorate (SMD). Consistent with NASA Earth Science Data and Information Policy, data from the GES DISC archive are available free to the user community. For more information visit the GES DISC Data Policy page.

References:

• The data set source should be properly cited when the data are used. A formal reference of the form: \, 2012, last updated 2013: \. NASA/GSFC, Greenbelt, MD, USA, NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). Accessed \ at \ is suggested following Parsons et al. (2010), doi:10.1029/2010EO340001.
• Mitchell 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 https://doi.org/10.1029/2003JD003823
• Xia et al (2012): Continental-scale water and energy flux analysis and validation for the North American Land Data Assimilation System project phase 2 (NLDAS-2): 1. Intercomparison and application of model products, J. Geophys. Res., 117, D03109. https://doi.org/10.1029/2011JD016048