Are the results of PILPS or GSWP affected by the lack of land surfaceatmosphere feedback

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Report of the GLASS workshop on land
atmosphere interaction Bart van den Hurk, Paul
Houser and Jan Polcher 19-20 April, 2002

• Are the results of PILPS or GSWP affected by the
  lack of land surface-atmosphere feedback?
• Is the use of offline land surface models in LDAS
  making optimal use of the assimilated data?
• We need experiments designed to quantify land
  atmosphere feedback in land surface modelling and
  data assimilation.
• This will take the next step in the complexity
  chain from offline land surface models to fully
  coupled GCMs.
• Focus on land atmosphere coupling by means of
  turbulent exchange, but discarding the processes
  related to radiation and precipitation.

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• The main scientific questions
• When and where does land atmosphere interaction
  play a significant role in the evolution of
  land-atmosphere fluxes and state variables?
• Does the absence of this coupling in PILPS-like
  calibration/evaluation experiments put a strong
  constraint on the general applicability of the
  results of these experiments?
• Is the solution of a land data assimilation
  experiment using an offline land surface model
  configuration different from a system that
  includes land atmosphere feedback?

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• PHASE 1
• GOAL Inventory conditions (climate, land cover
  and heterogeneity, synoptic situation) where
  modelled fluxes and state variables are sensitive
  to the land-atmosphere coupling.
• ACTION For a number of locations and time
  periods, the behaviour of land surface models in
  an offline and a coupled mode (using a SAM
  Simplified Atmospheric Model) will be compared.
  The SAM should be able to calculate the vertical
  exchange processes due to turbulence,
  thermodynamics and radiation, but does not
  necessarily supply the precipitation and
  radiation forcing to the land surface.
• PHASE 2
• GOAL Identify the nature of the land
  atmosphere coupling by varying the combinations
  land model boundary layer model in a systematic
  way.
• ACTION Use a common land atmosphere coupler
  (which is being established within the ALMA
  action of GLASS), and start with providing a
  single boundary layer model, to which a range of
  land surface models can be connected.
• PHASE 3
• GOAL The relation between data assimilation and
  land atmosphere feedback will be addressed.
• ACTION In this phase, a combination of an
  offline model and SCM should be allowed to
  assimilate additional data that are not present
  in the forcings already provided. These
  additional data could consist of surface state
  variables (soil moisture, snow), atmospheric
  quantities (screen level parameters, surface
  heating rates), surface fluxes or combinations of
  these obtained from co-located field experiments
  or remote sensing.

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Known Actions

• ELDAS Coupling TESSEL, the surface scheme in
  the DWD Lokal Modell, and the ISBA models to a
  common SCM and assimilation procedure.
• Individual Efforts
• Hoshin and Luis?
• Christa and Paul NASA-AIST coupling of LIS 1km
  global LSM to PBL model
• Others?

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The First International Local-Coupled Action
Field Experiment (FILCAFE)

• GOAL Collect a specifically targeted dataset to
  meet the objectives of the GLASS local-coupled
  action.
• A well-defined mesoscale hydrologic catchment
  (for surface water balance observations)
• Observations from groundwater table through PBL
• Include heterogeneity in elevation, vegetation,
  soils, climate (inc. snow), etc.
• Observation platforms
• In-situ weather, fluxes, snow, soil moisture,
  groundwater, vegetation
• Aircraft fluxes, temperature, moisture,
  microwave, etc.
• Soundings tethered
• Satellite various
• Questions
• What should the spatial scale and heterogeneity
  be?
• When, where, and how long?
• Is this experiment of interest?

• States
• Soil Moisture
• Groundwater
• Surface Water
• Temperature
• (soil, veg, air)
• Humidity
• Wind
• Pressure
• Snow
• Carbon
• Nitrogen
• Biomass

• Fluxes
• Evapotranspiration
• Sensible Heat Flux
• PBL fluxes
• Radiation
• Runoff
• Drainage
• Isotopes/carbon

• Parameters
• Soil Properties
• Vegetation Properties
• Elevation Topography
• Subgrid Variation
• Catchment Delineation
• River Connectivity

• Forcing
• Precipitation
• Wind profiles
• Humidity profiles
• Radiation
• Air Temperature profiles

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How do we get action on theGLASS local-coupled
action?Bart van den Hurk, Hoshin Gupta, Luis
Bastidas, Jan Polcher, Christa Peters-Lidard,
Paul HouserDevelop a Phase 1 experimental
planPut in place tools (SCM) and datasetsEngage
the community