Seasonal discharge response to temperature-driven changes in evaporation and snow processes in the Rhine Basin

Abstract

Abstract. This study analyses how temperature-driven changes in evaporation and snow processes influence the discharge in the Rhine Basin. Using an efficient distributed hydrological model at high spatio-temporal resolution, we performed two experiments to understand how changes in temperature affect the discharge. In the first experiment, we compared two 10-year periods (1980s and 2010s) to determine how changes in discharge can be related to changes in evaporation, snowfall, melt from snow and ice, and precipitation. By simulating these periods, we can exchange the forcing components (evaporation, temperature for snowfall and melt, and precipitation), to quantify their individual and combined effects on the discharge. Around half of the observed changes could be explained by the changes induced by temperature effects on snowfall and melt (10 %), temperature effects on evaporation (16 %), and precipitation (19 %), showing that temperature-driven changes in evaporation and snow (26 %) are larger than the precipitation-driven changes (19 %). The remaining 55 % was driven by the interaction of these variables: e.g. the type of precipitation (interaction between temperature and precipitation) or the amount of generated runoff (interaction between evaporation and precipitation). In the second experiment we exclude the effect of precipitation and run scenarios with realistically increased temperatures. These simulations show that discharge is generally expected to decrease due to the positive effect of temperature on (potential) evaporation. However, more liquid precipitation and different melt dynamics from snow and ice can slightly offset this reduction in discharge. Earlier snowmelt leaves less snowpack available to melt during spring, when it historically melts, and amplifies the discharge reduction caused by the enhanced evaporation. These results are tested over a range of rooting depths. This study shows how the combined effects of temperature-driven changes affect discharge. With many basins around the world depending on meltwater, a correct understanding of these changes and their interaction is vital.

Continuous Negotiation in Climate Adaptation: The Challenge of Co-Evolution for the Capability Approach to Justice

“…If there is less water available for flushing the Haringvliet and the Nieuwe Waterweg, there will be fewer days that the Haringvliet sluices can be opened under the conditions of the Kierbesluit. This reduces the effectivity of the Haringvliet Kierbesluit measure in its current form [77]. Besides, translating recent findings about the risk of accelerated melting of the Antarctic ice sheet, researchers find that saltwater intrusion may also intensify because of sea level rise.…”

“…(Details of the water management regime: The discharge volume of the Haringvliet sluices depends primarily on the river discharge of the Rhine at Lobith, near the German border. Between 2000 and 2011, it was measured that 24.2-30.4% of the Rhine discharge discharged into the sea via the Haringvliet sluices [77]. The average discharge of the Rhine river is 1960 m 3 /2 and the catchment area is around 170,000 km 2 .…”

“…The average discharge of the Rhine river is 1960 m 3 /2 and the catchment area is around 170,000 km 2 . The average discharge of the Meusse river is significantly smaller, 230 m 3 /s, and the catchment area is around 33.000 km 2 [76,77]).…”

Melting Alpine Water Towers Aggravate Downstream Low Flows: A Stress‐Test Storyline Approach

“…Such alternative modeling scenarios have been used in other contexts and studies, all aiming for (a) a better understanding of process changes and (b) system response related to practice and management during extreme conditions. Buitink et al (2021), e.g., swapped the model forcing between two different decades, i.e., temperature, precipitation, and evaporation, each in a separate hydrological model run, to disentangle their effects on streamflow changes in the Rhine basin. Stoelzle et al (2020) and Hellwig et al (2021) introduced a "stress-test" approach, in which past drought events were modeled and altered by reducing the groundwater recharge before the event for German catchments.…”

Mapping terrestrial evaporation regimes : a data-driven analysis of land-atmosphere interactions under climate change

“…Here, ET p is assumed to be a fraction (α MD = 0.8) of the surface net radiation. The Q leakage is based on Clapp and Hornberger Clapp and Hornberger (1978) and Buitink et al Buitink et al (2021):…”