Abstract
The CSIRO Mk3L climate system model, a
reduced-resolution coupled general circulation model, has
previously been described in this journal. The model is configured
for millennium scale or multiple century scale simulations.
This paper reports the impact of replacing the relatively
simple land surface scheme that is the default parameterisation
in Mk3L with a sophisticated land surface model
that simulates the terrestrial energy, water and carbon balance
in a physically and biologically consistent way. An
evaluation of the new model’s near-surface climatology highlights
strengths and weaknesses, but overall the atmospheric
variables, including the near-surface air temperature and precipitation,
are simulated well. The impact of the more sophisticated
land surface model on existing variables is relatively
small, but generally positive. More significantly, the
new land surface scheme allows an examination of surface
carbon-related quantities including net primary productivity
which adds significantly to the capacity of Mk3L. Overall,
results demonstrate that this reduced-resolution climate
model is a good foundation for exploring long time scale
phenomena. The addition of the more sophisticated land surface
model enables an exploration of important Earth System
questions including land cover change and abrupt changes in
terrestrial carbon storage.
