Myles Allan, Constraints for Probabilistic Forecasts Myles Allan ...

Neil MacKellar, REPRESENTING THE LAND SURFACE IN A REGIONAL
CLIMATE MODEL: WHAT ARE THE OPTIONS
Neil MacKellar
CSAG, University of Cape Town, South Africa
and
Mr Mark Tadross
Mr Bruce Hewitson
Numerous sensitivity studies have confirmed the importance of land-surface boundary
conditions in atmospheric modeling. It can therefore be inferred that, in order to work towards
increasing the accuracy of weather and climate simulations, it is essential to consider the
quality of land-surface data used by the model. Two possible sources for such data are satellite
observations and dynamic global vegetation models, each with its respective attractions and
caveats. In this study, the nature of some land-surface data sets available for southern Africa
are described, and the practicalities of how this information may be incorporated into Version 5
of the Penn State/NCAR Mesoscale Model (MM5) are explored. In addition, the Sheffield
Dynamic Global Vegetation Model (SDGVM) is employed to simulate a vegetation map for
use by MM5. The sensitivity of MM5 to using this simulated land surface as opposed to the
default configuration is assessed for a 3-month summer period. This represents a first step in
investigating the possibilities for a dynamic coupling of these two models.