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| Hauptseite > Publikationsdatenbank > Groundwater Effects on Terrestrial Systems in Europe: Evolution of Past Heatwaves |
| Hauptseite > Publikationsdatenbank > Groundwater Effects on Terrestrial Systems in Europe: Evolution of Past Heatwaves |
| Conference Presentation (Other) | FZJ-2022-00656 |
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2021
Abstract: Due to climate change, hot years in Europe (EU) will likely happen more often, causing frequent hydroclimatic extreme events (e.g., heavy precipitation, droughts, heatwaves) with multiple socio-economic impacts. Consistent climate data is needed for strategies on climate change mitigation and adaptation, but high-resolution hydroclimatic data at EU-scale is still lacking. Moreover, in most climate models, the groundwater (GW) representation and interaction with the atmosphere is generally simplified or missing, leading to biases in simulation of the extreme heat events.We investigate heat events evolution in EU from 1976 to 2005, based on an ensemble of regional climate models (RCMs) forced by global climate models. The ensemble is complemented with Terrestrial Systems Modelling Platform (TSMP) simulations, where full 3D soil and GW dynamics are explicitly represented, closing the terrestrial water cycle from the GW across the land surface into the atmosphere. From the comparison of TSMP and other RCMs lacking GW, we assess the effects of GW on the evolution of EU heatwaves by analysing their main characteristics such as frequency, duration and intensity.Our results show that heat events are differently impacted by GW, depending on the time span and region. Moreover, GW does not have explicit effects on the hot (air temperature exceeds the 90th percentile) days frequency. Hence we found out that GW affects the duration of heat events by decreasing the mean number of hot day events with a duration longer than 3 days. The mean number of long hot events (duration > 6 days) is decreased by a factor of 1.5-2.3. Also, there is an increase in the mean number of short hot events (duration < 3 days). Interestingly, the amplitude (intensity) of heatwaves (heat events exceeding 6 consecutive days) is affected by GW too — the frequency of heatwaves with an amplitude larger than 4°C, in comparison to the 90th temperature percentile, is decreased by a factor of 2 and more, while, the frequency of heatwaves with low amplitudes is increased. As conclusion, GW smooths out the heatwaves effect on terrestrial systems in EU.The results emphasize the importance of GW in RCMs, and its impact on heatwaves evolution. Further, this study will be extended to investigate the future evolution of heatwaves based on different climate change scenarios.
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