To develop a set of closure parameters (such as roughness
lenghts) pertinent to correct representation of average surface
fluxes in GCM's and climate models, and which take into account
the subgrid scale variability.
Observational, theoretical and modelling tools will be used to
obtain areal averages of surface fluxes of momentum, heat and
water vapour as well as the mean values of wind velocity,
temperature and humidity at levels relevant for GCM's and climate
The work will be concentrated on a specific area, where data from
a dense observational network is available, and which is
topographically of moderate complexity. The area is the Upper
Rhine Valley between Karlsruhe and Basel.
Satellite imagery will be used for the elaboration of land use
maps and for the monitoring of surface temperature in space and
time. Meteosat data will be used to provide high temporal
resolution of the temperature, and will be calibrated with AVHRR
data to achieve a higher spatial resolution. Landsat TM data will
be used together with digital elevation data for the elaboration
of the land use data.
Surface observations will be analysed in terms of the components
of the surface energy fluxes and the mean quantities. Vertical
profiles of pertinent meteorological parameters will be measured.
The surface measurements will cover areas typical of climate
model grid boxes and will be done over a number of typical sites.
The data will be analysed using microscale and mesoscale
modelling. A diagnostic microscale model will be operated for
integration of the information on the scale of the heterogenties
into suitable averages for mesoscale dynamical modelling (1 km
scale). A nonhydrostatic mesoscale model (KAMM) will be used to aggregate
the microscale exchange processes up to 100 km scales.
The end result will be the development of methods to compile
observational information into boundary conditions suitable for
GCM's and climate models, of methods to deal with subgrid
scale inhomogeneities, and of improved
surface flux parametrization schemes for use in such models.
Funding SchemeCSC - Cost-sharing contracts
97331-2209 Corvallis - Oregon