In order to quantify the impact of a mountain range on the incoming
atmospheric water vapor we examined the stable isotope ratios of
hydrogen and oxygen in streams and twigs an the lee side of a mountain
range. When compared with the isotopic ratios of the incoming airmass
is possible to calculate the proportion of water vapor rained out as it
passes the range, or the "Drying ratio".
Regional climate of the Middle East
As part of the South-West
Asia Project (SWAP) I have been attempting to model the
present day climate of the region. Various investigations into the
effects of changes in land-use, drought - vegetation feedacks, and
the transport and sources of water
vapor etc have been conducted. Experiments looking into
the future (ie. global warming scenarios), quantifying the predicted
impact on precipitation and temperature, changes in precipitation
processes and water vapor transport.
Regional climate modelling
I have been investigating the ability of several regional climate
models to reproduce the current energy and water balances over
multi-annual time scales.
The models (RegCM2, MM5/BATS, MM5/SHEELS, MM5/OSU) have been applied
over central USA. The domain is centered over the FIFE region in Kansas
where an intensive field
experiment was conducted and extensive data is available for evaluation
of the models.
While no model consistently performed better then the other models it
was found that during 'normal' conditions the various land-surface
schemes performed similarly but under stressed conditions (eg.
unusually dry) they behaved quite differently. While the atmospheric
radiation and precipitation parameterizations were important in
the driving forces at the surface, differences in the transfer of
momentum (eg. surface winds and drag coefficients) played a major role
in determining the split between latent and sensible heat.
Using numerical weather
models we investigate the influence of
topography on the initiation and continuation of precipitation events.
This was done over the European Alps in cooperation with the
Mesoscale Alpine Project (MAP).
Water quality research
I have been involved in studies looking at identifying relationships
between catchment characteristics and in-stream phosphorus. These
used reasonably large in-stream phosphorus data sets collected in the
basin in South East Australia. Slope and intensive agriculture within
of the stream seem to be the two most important catchment
observed to date.
Much of the work I have done involves hydrological modelling of some
sort. The rainfall-runoff model I have used most is IHACRES. It is a
conceptual model which has minimum data requirements (rainfall,
and temperature) and only a small number of parameters (~7). This model
has been applied in many places around the world, under many different
climatic conditions often performing better than more complex models. I
have applied it successfully to many catchments, from temperate, humid
catchments in South East Australia to semi-arid catchments in inland
South Wales (NSW), Australia to tropical monsoonal catchments of
Land surface/atmosphere Interaction modelling
Much of the hydrological modelling has been concerned with the climates
on the surface hydrology, of particular interest here is the feedback
the climate from the land surface hydrology. This interaction is given
by the exchange of energy and water fluxes at the surface. Both of
fluxes are embodied (to a large extent) in the evaporative flux. In
to investigate this interaction a new version of IHACRES was developed
which explicitly calculated the evaporation each time step without
extra data and keeping the number of parameters to a minimum. The model
is based on the catchment moisture deficit (CMD) which is a measure of
how far from saturation a catchment is. CMD-IHACRES has been
tested and shown to provide streamflow results as good as IHACRES while
still providing the evaporation estimates. The model structure also
evaporation and streamflow to be dealt with using different time steps.
Climate Change Impacts
The impacts of climate change on streamflows has been investigated
using different techniques. Around Perth, Australia results from a
Climate Model (GCM) were spatially downscaled and temporally extended
a stochastic weather generator. This created climatic time series was
used in conjunction with CMD-IHACRES to provide estimates of the
response to the climate change. Also in the Middle East, GCM results
downscaled using a regional climate model enabling investigation into
changing precipitation processes and water vapor transport.
Land Use Change Impacts
A study into the effects of increasing numbers of farm dams on the
streamflow was conducted in the Namoi basin, NSW, Australia. This study
used CMD-IHACRES to estimate the streamflow response to these changes.
I was involved in the creation of the methodology used to examine this
response. This study found that rarely in an active agricultural
will only one land use change occur at a time, usually there are many
users and hence many changes occurring at once. This makes
of results difficult at times, though in several cases we found
trends in the streamflow response.
Integrated Water Resource Assessment and Management
With the Integrated Catchment Assessment and Management (iCAM) centre
I have been involved in an integrated water resource assessment and
project in northern Thailand. The aim of this ongoing project is to
bio-physical and socio-economical knowledge into a decision support
for use by the stakeholders involved especially those responsible for