Welcome to the PILPS homepage. PILPS is part of the Global Land Atmosphere System Study (GLASS) which aims to foster an evaluation of the next generation of land-surface schemes and to coordinate the evaluation of land-surface schemes in their different applications. GLASS is a GEWEX project which serves as an interface between the land-surface community and other WCRP projects. We are also affiliated with IGBP, particularly ILEAPS.


Within GLASS, PILPS (the Intercomparison of Land-surface Parameterization Schemes) operates off-line intercomparisons of land-surface schemes (LSSs). The goal of PILPS is to contribute improved understanding of continental surface and near-surface processes through international intercomparison of current state-of-the-art parameterization schemes employed in coupled climate, atmospheric and earth system models.


Since the early 1990s PILPS has evaluated the parameterization of energy and water fluxes to/from the land-atmosphere interface (e.g. Pitman et al., 1999). More recently carbon fluxes and isotopes have been included in this land-surface MIP (Vivoy, 2002).

Highlights to Date

  • Discovered a clear chronological sequence of: first generation 'no canopy' (e.g. Manabe); second generation (e.g. SiB & BATS) ; and 'recent' land-surface schemes showing that, while three decades of research have improved continental surface modelling capability, full confidence in our ability to project land-surface quantities remains elusive, in part due to uncertainties in surface observations.
  • Collected 17 papers in the landmark ACSYS/PILPS Torne-Kalix Basin study & published in Special Issue of Global and Planetary Change July 2003.
  • Discovered several classes of LSS carbon behaviour: rapid equilibrium of NPP with important CO2 sinks early in the simulation cf. a more gradual increase of NPP beginning with a null CO2 net sink. In PILPS C1 the total living biomass simulated varies from 1 kg of carbon to 16 kg of carbon and from 1kg to 10 kg of carbon in the soil (observed soil carbon at the Loobos test site is around 7 kg).
  • In AMIP II demonstrated that different land-surface schemes (LSSs) interact differently with different atmospheric forcing and exhibit a range of climate sensitivity and hence shown that LSSs are important to GCM predictions such that new, or changed, land-surface components will increase diversity among climate simulations.
  • Determined that VIC (an off-line land-surface scheme) is a better surrogate for global surface observations than any reanalyses for evaluation of simulation of continental surface water budgets

Future Plans