Assessing uncertainties in climate change impacts on runoff in Western Mediterranean basins
This paper investigates the uncertainties linked to climate change impacts on runoff in four mesoscale basins (900 to 1800 km<sup>2</sup>) in the Mediterranean region. Runoff simulations were based on a daily conceptual model including a snow module. The model was calibrated and valid...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Proceedings of the International Association of Hydrological Sciences |
| Online Access: | https://www.proc-iahs.net/371/75/2015/piahs-371-75-2015.pdf |
| Summary: | This paper investigates the uncertainties linked to climate change impacts
on runoff in four mesoscale basins (900 to 1800 km<sup>2</sup>) in
the Mediterranean region. Runoff simulations were based on a daily conceptual model
including a snow module. The model was calibrated and validated according to
a differential split-sample test over a 20-year period and four competing
criterions aiming to represent model structural uncertainty based on the
concept of Pareto optimality. Five regional climate models (RCMs) from the
Med-CORDEX initiative were used to provide temperature and precipitation
projections under RCP8.5 by 2050. The RCMs' inability to realistically
simulate reference climate (notably precipitation) led us to apply a monthly
perturbation method in order to produce a range of climate scenarios. The
structural uncertainty bounds obtained from the hydrological simulations
over the reference period showed that the model was able to correctly
reproduce observed runoff despite contrasted hydrological conditions in (and
in between) the basins. Climate projections were shown to be convergent
regarding temperatures, which could increase by about +1 to
3 °C on each basin. In contrast, no clear trends in precipitation
could be put in evidence, some RCMs leading to a mean annual precipitation
decrease (up to 64%), and others to an increase (up to 33%). The
hydrological projections resulted from the combination of the hydrological
simulation bounds with the range of climate projections. Despite the
propagation of those uncertainties, the 2050 hydrological scenarios agreed
on a significant runoff decrease (2–77%) during spring on all basins. On
the opposite, no clear trend in runoff could be observed for the other
seasons. |
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| ISSN: | 2199-8981 2199-899X |