About GSWP2

    The Global Soil Wetness Project (GSWP) is an ongoing environmental modeling research activity of the Global Land-Atmosphere System Study (GLASS) a project of the Global Energy and Water Cycle Experiment (GEWEX) within the World Climate Research Programme (WCRP).
 The goals of GSWP are to:

•    Produce state-of-the-art global data sets of land surface fluxes, state variables, and related hydrologic quantities.
•    Develop and test large-scale validation, calibration, and assimilation techniques over land.
•    Provide a large-scale validation and quality check of the International Satellite Land-Surface Climatology Project (ISLSCP) global data sets.
•    Compare Land Surface Schemes (LSSs), and conduct sensitivity studies of specific parameterizations and forcings, which should aid future model and data set development. 

    GSWP-2 is closely linked to the ISLSCP Initiative II data effort, and LSS simulations in GSWP-2 encompass the same core 10-year period as ISLSCP Initiative II (1986-1995).

    There are five basic categories of participants in GSWP-2: the operational centers, the land-surface modelers, evaluators of the model output, those involved in remote sensing applications, and other end users of the model output.  There are two operational centers for GSWP.  The Center for Ocean-Land-Atmosphere Studies (COLA) produced the forcing data sets and is the principal center for managing the project.  The Inter-Comparison Center at the University of Tokyo collects results from participating models, perform consistency checks, basic comparisons, and redistributes the data.

    This DVD represents the  major product of GSWP-2; a multi-model land surface analysis for the ISLSCP Initiative II period.  This can be considered  a land surface analog to the atmospheric reanalyses, and include estimates of uncertainties based on inter-model spread.  The science plan also includes in situ validation with data from field campaigns, observational networks and long-term monitoring sites.  Modeling sensitivity studies involve re-integrating the LSSs to test the response of the models to changes in meteorological data (including choice of reanalysis products, impacts of bias correction, sensitivity to the range in observational estimates, and impacts of rain-gauge under-catch) and surface parameters.

    A new thrust for GSWP-2 is a stronger connection to applications in remote sensing.  In addition to the classical attempts to validate the typical land-surface state variables using satellite retrievals, GSWP-2 also intends to expand the validation and assimilation capabilities of current LSSs.  This is being done by the development and application of algorithms by which multile LSSs can directly report brightness temperatures, like those sensed by instruments in orbit. 

    All data sets conform to the Assistance for Land-surface Modeling Activities (ALMA) standards set forth by GLASS, and now widely adopted by intercomparison studies and land data assimilation efforts around the world.

gswp@cola.iges.org