Tributaries affect the thermal response of lakes to climate change
Thermal responses of inland waters to climate change varies on global and regional scales. The extent of warming is determined by system-specific characteristics such as fluvial input. Here we examine the impact of ongoing climate change on two alpine tributaries, the Aare River and the Rhône Riv...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-01-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/22/31/2018/hess-22-31-2018.pdf |
| Summary: | Thermal responses of inland waters to climate change varies on global and
regional scales. The extent of warming is determined by system-specific
characteristics such as fluvial input. Here we examine the impact of ongoing
climate change on two alpine tributaries, the Aare River and the Rhône River,
and their respective downstream peri-alpine lakes: Lake Biel and Lake
Geneva. We propagate regional atmospheric temperature effects into river
discharge projections. These, together with anthropogenic heat sources, are
in turn incorporated into simple and efficient deterministic models that
predict future water temperatures, river-borne suspended sediment
concentration (SSC), lake stratification and river intrusion depth/volume in
the lakes. Climate-induced shifts in river discharge regimes, including
seasonal flow variations, act as positive and negative feedbacks in
influencing river water temperature and SSC. Differences in temperature and
heating regimes between rivers and lakes in turn result in large seasonal
shifts in warming of downstream lakes. The extent of this repressive effect
on warming is controlled by the lakes hydraulic residence time. Previous
studies suggest that climate change will diminish deep-water oxygen renewal
in lakes. We find that climate-related seasonal variations in river
temperatures and SSC shift deep penetrating river intrusions from summer
towards winter. Thus potentially counteracting the otherwise negative effects
associated with climate change on deep-water oxygen content. Our findings
provide a template for evaluating the response of similar hydrologic systems
to on-going climate change. |
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| ISSN: | 1027-5606 1607-7938 |