Fourth Study Conference on BALTEX Scala Cinema Gudhjem

depending on the availability and climatic conditions (Xu,
2002). It has few parameters, all of which can be related to
physical catchment characteristics at different spatial scales.
It has been successfully applied in Europe to ungauged
catchments in Belgium, Sweden and Denmark (Xu, 1999,
Müller-Wohlfeil et al., 2003). WASMOD-M is presently
running on the global scale. This study is a first step towards
applying it to a smaller continental scale, initially the Baltic-
Sea and the Yellow-River basins.
The level of complexity, i.e., the degree to which different
processes can be explicitly incorporated in a global- or
continental-scale model primarily depends on the presence
and quality of input and validation data. With a given
dataset, we will compare different process formulations to
evaluate model sensitivity to this.
4. Data
WASMOD-M is run globally with freely available datasets.
Precipitation, temperature and vapour, gridded to 0.5 o × 0.5 o
(lat-long), are taken from CRU TS 2.0 (Mitchell et al.
submitted). Catchment boundaries and flow paths at the
same resolution are taken from the STN-30p dataset
(Vörösmarty et al., 2000). This dataset has been coregistered
with GRDC gauging stations in the work with
“UNH-GRDC Composite Runoff Fields” (Fekete et al.
1999). Since these runoff data are only provided as longterm
averages, monthly runoff data for model tuning and
validation are taken from the GHCDN dataset (Dettinger
and Diaz, 2000). A subset of the GHCDN stations fitting the
co-registered stations by Fekete et al. (1999) was chosen.
Land-use data are from the UMD 8-km global classification
by Hansen et al. (2000).
5. Continental-scale application
The continental-scale project is open for collaboration and
we are looking forward to establish contacts with
hydrologists, climatologists, and meteorologists working in
either the Baltic-Sea or the Yellow-River regions.
We are presently investigating the availability of highquality
data with a higher spatial resolution than 0.5 o × 0.5 o
before we can delimit the boundaries of the continental-scale
applications. Preliminary results with the global-scale
resolution over northern-Europe show that the model, which
is not calibrated in the traditional sense, is “reasonably”
accurate. It has problems to simulate runoff in some areas,
partly because the model has no distribution of properties
(e.g., precipitation) within the cells and partly because the
model does not account for transmission losses in the river
channel.
References
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Dettinger, M.D., Diaz, H.F. Global Characteristics of Stream
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