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
the operational centers, the land-surface modelers, evaluators of the
output, those involved in remote sensing applications, and other end
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
All data sets conform to the Assistance for
Modeling Activities (ALMA) standards set forth by GLASS, and now widely
adopted by intercomparison studies and land data assimilation efforts
around the world.