11 research outputs found
Recurrence of Drought Events Over Iberia. Part II: Future Changes Using Regional Climate Projections
ZukĂŒnftige Ănderungen der Windenergie-Potentiale ĂŒber Europa in einem groĂen CMIP5 Multi-Modell Ensemble
KlimafolgenIn dieser Studie wird ein statistisch-dynamisches (SDD) Regionalisierungs-Verfahren verwendet, welches es ermöglicht regionale Windenergie-Potenziale (WEP) fĂŒr das gegenwĂ€rtige und das zukĂŒnftige Klima aus einem sehr groĂen GCM Ensemble zu bestimmen. Das SDD benutzt zum einen eine Wetterlagen-Klassifizierung, und zum anderen das Regional-Modell COSMO-CLM (0.22°) um regionale Windfelder einzelner ReprĂ€sentanten dieser Wetterlagen zu simulieren. Insgesamt werden 22 CMIP5 Modelle in dieser Studie betrachtet. ZukĂŒnftige Ănderungen der WEP ĂŒber Europa in diesen 22 CMIP5 Modellen werden fĂŒr die kommenden Jahrzehnte (2021-2060) sowie fĂŒr die zweite HĂ€lfte des 21. Jahrhunderts (2061-2100) in einem RCP4.5 und einem RCP8.5 Szenario bestimmt. Das CMIP5 Ensemble-Mittel weist fĂŒr beide zukĂŒnftigen ZeitrĂ€ume und Szenarien auf eine Zunahme der jĂ€hrlichen WEP ĂŒber Nord- und Mitteleuropa und auf eine Abnahme ĂŒber SĂŒdeuropa hin. GroĂe Unterschiede zeigen sich bei der Betrachtung der einzelnen Modelle, sowohl im Hinblick auf die StĂ€rke als auch auf das Vorzeichen der Ănderung. Eindeutigere Ergebnisse zeigen sich hingegen fĂŒr spezielle Jahreszeiten. Vor allem fĂŒr die 2. HĂ€lfte des 21. Jahrhunderts wird fĂŒr die meisten Modelle ĂŒber Nord- und Zentraleuropa mehr WEP im Winter und weniger WEP im Sommer festgestellt. Dies hĂ€tte eine starke Zunahme der intra-annualen VariabilitĂ€t zur Folge. Generell sind die genannten Ănderungen fĂŒr 2061-2100 und dem RCP8.5 Szenario stĂ€rker als fĂŒr 2021-2060 und dem RCP4.5 Szenario. Sehr groĂe Unsicherheiten zwischen den CMIP5 Modellen herrschen bezĂŒglich der inter-annualen VariabilitĂ€t von WEP in einem zukĂŒnftigen Klima. Die Zukunfts-Prognosen variieren je nach Modell zwischen einer Abnahme der VariabilitĂ€t um mehr als 40% und einer Zunahme von knapp 50%. Auch innerhalb einzelner Modelle zeigen sich je nach zukĂŒnftigem Zeitraum oder Szenario zum Teil gegenteilige Trends. Insgesamt zeigt diese Studie, dass eine generelle Ănderung der WEP ĂŒber Europa in einem zukĂŒnftigen Klima wahrscheinlich ist. Nichtsdestoweniger sind aufgrund der gefundenen Unsicherheiten weitere Untersuchungen mit Multi-Modell Ensembles nötig und sinnvoll
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Decadal predictability of regional scale wind speed and wind energy potentials over Central Europe
Decadal predictions on timescales from one year to one decade are gaining importance since this time frame falls within the planning horizon of politics, economy and society. The present study examines the decadal predictability of regional wind speed and wind energy potentials in three generations of the MiKlip (âMittelfristige Klimaprognosenâ) decadal prediction system. The system is based on the global Max-Planck-Institute Earth System Model (MPI-ESM), and the three generations differ primarily in the ocean initialisation. Ensembles of uninitialised historical and yearly initialised hindcast experiments are used to assess the forecast skill for 10 m wind speeds and wind energy output (Eout) over Central Europe with lead times from one year to one decade. With this aim, a statistical-dynamical downscaling (SDD) approach is used for the regionalisation. Its added value is evaluated by comparison of skill scores for MPI-ESM large-scale wind speeds and SDD-simulated regional wind speeds. All three MPI-ESM ensemble generations show some forecast skill for annual mean wind speed and Eout over Central Europe on yearly and multi-yearly time scales. This forecast skill is mostly limited to the first years after initialisation. Differences between the three ensemble generations are generally small. The regionalisation preserves and sometimes increases the forecast skills of the global runs but results depend on lead time and ensemble generation. Moreover, regionalisation often improves the ensemble spread. Seasonal Eout skills are generally lower than for annual means. Skill scores are lowest during summer and persist longest in autumn. A large-scale westerly weather type with strong pressure gradients over Central Europe is identified as potential source of the skill for wind energy potentials, showing a similar forecast skill and a high correlation with Eout anomalies. These results are promising towards the establishment of a decadal prediction system for wind energy applications over Central Europe
Nonâlinear plantâplant interactions modulate impact of extreme drought and recovery on a Mediterranean ecosystem
Interaction effects of different stressors, such as extreme drought and plant invasion, can have detrimental effects on ecosystem functioning and recovery after drought. With ongoing climate change and increasing plant invasion, there is an urgent need to predict the short- and long-term interaction impacts of these stressors on ecosystems.
We established a combined precipitation exclusion and shrub invasion (Cistus ladanifer) experiment in a Mediterranean cork oak (Quercus suber) ecosystem with four treatments: (1) Q. suber control; (2) Q. suber with rain exclusion; (3) Q. suber invaded by shrubs; and (4) Q. suber with rain exclusion
In an average precipitation year, the interaction effects of both stressors were neutral. However, the combination of imposed drought and shrub invasion led to amplifying interaction effects during an extreme drought by strongly reducing tree transpiration. Contrarily, the imposed drought reduced the competitiveness of the shrubs in the following recovery period, which buffered the negative effects of shrub invasion on Q. suber.
Our results demonstrate the highly dynamic and nonlinear effects of interacting stressors on ecosystems and urges for further investigations on biotic interactions in a context of climate change pressures
Skill and added value of the MiKlip regional decadal prediction system for temperature over Europe
In recent years, several decadal prediction systems have been developed to provide multi-year predictions of the climate for the next 5â10âyears. On the global scale, high decadal predictability has been identified for the North Atlantic sector, often extending over Europe. The first full regional hindcast ensemble, derived from dynamical downscaling, was produced within the German MiKlip project (âdecadal predictionsâ). The ensemble features annual starting dates from 1960 to 2017, with 10 decadal hindcasts per starting year. The global component of the prediction system uses the MPI-ESM-LR and the downscaling is performed with the regional climate model COSMO-CLM (CCLM). The present study focusses on a range of aspects dealing with the skill and added value of regional decadal temperature predictions over Europe. The results substantiate the added value of the regional hindcasts compared to the forcing global model as well as to un-initialized simulations. The results show that the hindcasts are skilful both for annual and seasonal means, and that the scores are comparable for different observational reference data sets. The predictive skill increases from earlier to more recent start-years. A recalibration of the simulation data generally improves the skill further, which can also be transferred to more user-relevant variables and extreme values like daily maximum temperatures and heating degree-days. These results provide evidence of the potential for the regional climate predictions to provide valuable climate information on the
Abstract
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In recent years, several decadal prediction systems have been developed to provide multi-year predictions of the climate for the next 5â10âyears. On the global scale, high decadal predictability has been identified for the North Atlantic sector, often extending over Europe. The first full regional hindcast ensemble, derived from dynamical downscaling, was produced within the German MiKlip project (âdecadal predictionsâ). The ensemble features annual starting dates from 1960 to 2017, with 10 decadal hindcasts per starting year. The global component of the prediction system uses the MPI-ESM-LR and the downscaling is performed with the regional climate model COSMO-CLM (CCLM). The present study focusses on a range of aspects dealing with the skill and added value of regional decadal temperature predictions over Europe. The results substantiate the added value of the regional hindcasts compared to the forcing global model as well as to un-initialized simulations. The results show that the hindcasts are skilful both for annual and seasonal means, and that the scores are comparable for different observational reference data sets. The predictive skill increases from earlier to more recent start-years. A recalibration of the simulation data generally improves the skill further, which can also be transferred to more user-relevant variables and extreme values like daily maximum temperatures and heating degree-days. These results provide evidence of the potential for the regional climate predictions to provide valuable climate information on the decadal time-scale to users
Windstorm losses in Europe : What to gain from damage datasets
Windstorms are among the most impacting natural hazards affecting Western and Central Europe. Information on the associated impacts and losses are essential for risk assessment and the development of adaptation and mitigation strategies. In this study, we compare reported and estimated windstorm losses from five datasets belonging to three categories: Indices combining meteorological and insurance aspects, natural hazard databases, and loss reports from insurance companies. We analyse the similarities and differences between the datasets in terms of reported events, the number of storms per dataset and the ranking of specific storm events for the period October 1999 to March 2022 across 21 European countries. A total of 94 individual windstorms were documented. Only 11 of them were reported in all five datasets, while the large majority (roughly 60%) was solely recorded in single datasets. Results show that the total number of storms is different in the various datasets, although for the meteorological indices such number is fixed a priori. Additionally, the datasets often disagree on the storm frequency per winter season. Moreover, the ranking of storms based on reported/estimated losses varies in the datasets. However, these differences are reduced when the ranking is calculated relative to storm events that are common in the various datasets. The results generally hold for losses aggregated at European and at country level. Overall, the datasets provide different views on windstorm impacts. Thus, to avoid misleading conclusions, we use no dataset as âground truthâ but treat all of them as equal. We suggest that these different views can be used to test which features are relevant for calibrating windstorm models in specific regions. Furthermore, it could enable users to assign an uncertainty range to windstorm losses. We conclude that a combination of different datasets is crucial to obtain a representative picture of windstorm associated impacts
Impact of climate change on backup energy and storage needs in wind-dominated power systems in Europe
The high temporal variability of wind power generation represents a major challenge for the realization of a sustainable energy supply. Large backup and storage facilities are necessary to secure the supply in periods of low renewable generation, especially in countries with a high share of renewables. We show that strong climate change is likely to impede the system integration of intermittent wind energy. To this end, we analyze the temporal characteristics of wind power generation based on high-resolution climate projections for Europe and uncover a robust increase of backup energy and storage needs in most of Central, Northern and North-Western Europe. This effect can be traced back to an increase of the likelihood for long periods of low wind generation and an increase in the seasonal wind variability
The regional MiKlip decadal prediction system for Europe: Hindcast skill for extremes and userâoriented variables
Regional climate predictions for the next decade are gaining importance, as this period falls within the planning horizon of politics, economy, and society. The potential predictability of climate indices or extremes at the regional scale is of particular interest. The German MiKlip project (âmidâterm climate forecastâ) developed the first regional decadal prediction system for Europe at 0.44° resolution, based on the regional model COSMOâCLM using global MPIâESM simulations as boundary conditions. We analyse the skill of this regional system focussing on extremes and userâoriented variables. The considered quantities are related to temperature extremes, heavy precipitation, wind impacts, and the agronomy sector. Variables related to temperature (e.g., frost days, heat wave days) show high predictive skill (anomaly correlation up to 0.9) with very little dependence on leadâtime, and the skill patterns are spatially robust. The skill patterns for precipitationârelated variables (e.g., heavy precipitation days) and windâbased indices (like storm days) are less skilful and more heterogeneous, particularly for the latter. Quantities related to the agronomy sector (e.g., growing degree days) show high predictive skill, comparable to temperature. Overall, we provide evidence that decadal predictive skill can be generally found at the regional scale also for extremes and userâoriented variables, demonstrating how the utility of decadal predictions can be substantially enhanced. This is a very promising first step towards impactârelated modelling at the regional scale and the development of individual userâoriented products for stakeholders.The skill of the regional MiKlip decadal prediction system is analysed focussing on extremes and userâoriented variables. Variables related to temperature extremes and the agronomy sector show high predictive skill with very little dependence on leadâtime. Skill patterns for precipitationârelated variables and windâbased indices are less skilful and more heterogeneous, especially for the latter.The study was mainly funded by the Bundesministerium fĂŒr Bildung und Forschung (BMBF) under project FONA MiKlipâII
http://dx.doi.org/10.13039/501100002347AXA Research Fund
http://dx.doi.org/10.13039/50110000196