New and Improved GLDAS and NLDAS data sets and data services at HDISC/NASA

Terrestrial hydrological variables are important in global hydrology, climate, and carbon cycle studies. To generate global fields of these variables, however, is still a challenge. The goal of a land data assimilation system (LDAS) is to ingest satellite- and ground-based observational data products, using advanced land surface modeling and data assimilation techniques, in order to generate optimal fields of land surface states and fluxes data and, thereby, facilitate hydrology and climate modeling, research, and forecast. NLDAS (North American LDAS) and GLDAS (Global LDAS) data are produced by specific instances of the Land Information System (LIS) software framework for high-performance land-surface modeling and data assimilation. LIS is developed by the Hydrological Sciences Branch at NASA Goddard Space Flight Center. NLDAS is a collaboration project between several groups (NOAA/NCEP/EMC, NASA/GSFC, Princeton Univ., Univ. of Washington, NOAA/OHD, and NOAA/NCEP/CPC) and is a core project of NOAA/CPPA. GLDAS is supported by the NASA Energy and Water cycle Study (NEWS). To date, both NLDAS and GLDAS have produced more than 30 years (1979 to present) of quality-controlled, spatially and temporally consistent, land-surface model data. Both data sets have recently been improved. The GLDAS Version 2 (GLDAS-2) data have now been released to the public. The GLDAS-2 NOAH model provides 3-hourly and monthly data at 1 and 0.25 degree resolutions and covers a period of more than 60 years (from 1948 to present). Other GLDAS-2 models (CLM, Catchment, and VIC) provide 3-hourly and monthly data at 1 degree resolution from 2001 onwards. With the extended temporal coverage, the GLDAS-2 data are expected to play an even more important role in global hydrology and climate studies. The 30-year hourly 0.125 degree resolution NLDAS Phase 2 (NLDAS-2) data were released at the end of 2009 and continue to be produced with a typically 2-4 day lag from the present. Additionally, the NLDAS Phase 1 data (1996 - 2007) were recently added to the GES DISC archives and released to the public, to continue to serve users of NLDAS-1 data and allow easier comparisons between the two phases of NLDAS. All NLDAS and GLDAS data are accessible from the Hydrology Data and Information Services Center (HDISC) at the NASA GES DISC (http://disc.sci.gsfc.nasa.gov/hydrology). This presentation will cover the basic characteristics of each data set; the major differences between GLDAS-2 and GLDAS-1, and NLDAS-2 and NLDAS-1; as well as data access and exploration tools, such as Mirador searching and ordering, parameter subsetting and file format conversion, and Giovanni online visualization and analysis. The presentation will also provide GLDAS and NLDAS application examples, such as NLDAS for summer precipitation diurnal cycle, NLDAS for the BASINS (Better Assessment Science Integrating point and Nonpoint Sources) project and drought monitoring, and GLDAS for initializing short-term and seasonal numerical weather prediction systems and developing climatology of water cycle components at continental to global scales.