Abstract
As humans alter landscape, vegetation, climate and atmospheric
composition, changes in the terrestrial water balance and fresh water
resources are likely to occur. Understanding how climate, vegetation,
humans and hydrology interact is key for accurate projections of future
fresh water resources. In this study we focus on forest dominated Sweden
where significant changes in climate and increasing human activity have
co-occurred during the past 50 years. For 280 catchments in Sweden, we
related runoff coefficients and change trends thereof to land-surface
characteristics. With these relationships we created average and change
trend maps for runoff and evapotranspiration across Sweden. All this
information is summarized by plotting water use efficiency (actual
evapotranspiration (ET)/precipitation) against energy use efficiency
(actual ET/potential ET ) in a Budyko-type framework for areas with
unique land cover across Sweden. This plot clearly shows that wetlands
tend to have lower water and energy use efficiencies compared to 'open
waters', forests and agriculture, and that agriculture and forests have
comparable water and energy use efficiencies closest to those of 'open
waters'. These results demonstrate how a change in land cover driven by
climate change or by humans is likely to alter land-cover-atmosphere
interactions, thereby changing both the water and energy balance of
catchments. Looking at runoff coefficient change trends during the last
50 years we see that forests tended to become more efficient in using
water and energy (i.e. the fractions of water and energy converted into
river runoff and heat decreased). As this behavior coincides with an
increase in precipitation it signals an acceleration of the hydrological
cycle of Swedish forests. In this presentation we will discuss these
findings focusing on the impact of forests on river discharges and the
implications for future water cycles.
Original language | English |
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Pages | 5 |
Publication status | Published - 1 Dec 2013 |
Keywords
- 1834 HYDROLOGY Human impacts
- 1804 HYDROLOGY Catchment
- 1807 HYDROLOGY Climate impacts
- 1813 HYDROLOGY Eco-hydrology