TY - GEN A1 - Casanueva, Anna A1 - Keuler, Klaus A1 - Kotlarski, Sven A1 - Herrera, Sixto A1 - Fernández, Jésus A1 - Gutiérrez, J. M. A1 - Boberg, Fredrik A1 - Colette, Augustin A1 - Bøssing Christensen, Ole A1 - Goergen, Klaus A1 - Jacob, Daniela A1 - Nikulin, Grigory A1 - Teichmann, Claas A1 - Vautard, Robert T1 - Daily precipitation statistics in a EURO-CORDEX RCM ensemble: Added value of raw and bias-corrected high-resolution simulations T2 - Climate Dynamics N2 - Daily precipitation statistics as simulated by the ERA-Interim-driven EURO-CORDEX regional climate model (RCM) ensemble are evaluated over two distinct regions of the European continent, namely the European Alps and Spain. The potential added value of the high-resolution 12 km experiments with respect to their 50 km resolution counterparts is investigated. The statistics considered consist of wet-day intensity and precipitation frequency as a measure of mean precipitation, and three precipitation-derived indicators (90th percentile on wet days—90pWET, contribution of the very wet days to total precipitation—R95pTOT and number of consecutive dry days—CDD). As reference for model evaluation high resolution gridded observational data over continental Spain (Spain011/044) and the Alpine region (EURO4M-APGD) are used. The assessment and comparison of the two resolutions is accomplished not only on their original horizontal grids (approximately 12 and 50 km), but the high-resolution RCMs are additionally regridded onto the coarse 50 km grid by grid cell aggregation for the direct comparison with the low resolution simulations. The direct application of RCMs e.g. in many impact modelling studies is hampered by model biases. Therefore bias correction (BC) techniques are needed at both resolutions to ensure a better agreement between models and observations. In this work, the added value of the high resolution (before and after the bias correction) is assessed and the suitability of these BC methods is also discussed. Three basic BC methods are applied to isolate the effect of biases in mean precipitation, wet-day intensity and wet-day frequency on the derived indicators. Daily precipitation percentiles are strongly affected by biases in the wet-day intensity, whereas the dry spells are better represented when the simulated precipitation frequency is adjusted to the observed one. This confirms that there is no single optimal way to correct for RCM biases, since correcting some distributional features typically leads to an improvement of some aspects but to a deterioration of others. Regarding mean seasonal biases before the BC, we find only limited evidence for an added value of the higher resolution in the precipitation intensity and frequency or in the derived indicators. Thereby, evaluation results considerably depend on the RCM, season and indicator considered. High resolution simulations better reproduce the indicators’ spatial patterns, especially in terms of spatial correlation. However, this improvement is not statistically significant after applying specific BC methods. KW - dded value; Bias correction; EURO-CORDEX; Precipitation indices; Regional climate models Y1 - 2016 U6 - https://doi.org/10.1007/s00382-015-2865-x SN - 1432-0894 VL - 47 IS - 3/4 SP - 719 EP - 737 ER - TY - GEN A1 - Prein, Andreas A1 - Gobiet, Andreas A1 - Truhetz, Heimo A1 - Keuler, Klaus A1 - Goergen, Klaus A1 - Teichmann, Claas A1 - Fox Maule, C. A1 - Meijgaard, Erik van T1 - Precipitation in the EURO-CORDEX 0.11° and 0.44° simulations: high resolution, high benefits? T2 - Climate Dynamics N2 - In the framework of the EURO-CORDEX initiative an ensemble of European-wide high-resolution regional climate simulations on a 0.11∘(∼12.5km) grid has been generated. This study investigates whether the fine-gridded regional climate models are found to add value to the simulated mean and extreme daily and sub-daily precipitation compared to their coarser-gridded 0.44∘(∼50km) counterparts. Therefore, pairs of fine- and coarse-gridded simulations of eight reanalysis-driven models are compared to fine-gridded observations in the Alps, Germany, Sweden, Norway, France, the Carpathians, and Spain. A clear result is that the 0.11∘ simulations are found to better reproduce mean and extreme precipitation for almost all regions and seasons, even on the scale of the coarser-gridded simulations (50 km). This is primarily caused by the improved representation of orography in the 0.11∘ simulations and therefore largest improvements can be found in regions with substantial orographic features. Improvements in reproducing precipitation in the summer season appear also due to the fact that in the fine-gridded simulations the larger scales of convection are captured by the resolved-scale dynamics . The 0.11∘ simulations reduce biases in large areas of the investigated regions, have an improved representation of spatial precipitation patterns, and precipitation distributions are improved for daily and in particular for 3 hourly precipitation sums in Switzerland. When the evaluation is conducted on the fine (12.5 km) grid, the added value of the 0.11∘ models becomes even more obvious. KW - Regional climate modeling KW - EURO-CORDEX KW - Extremes Y1 - 2016 U6 - https://doi.org/10.1007/s00382-015-2589-y SN - 0930-7575 SN - 1432-0894 VL - 46 IS - 1 SP - 383 EP - 412 ER - TY - GEN A1 - Knist, Sebastian A1 - Goergen, Klaus A1 - Keuler, Klaus T1 - Land-atmosphere coupling in EURO-CORDEX evaluation experiments T2 - Journal of Geophysical Research Atmosperes N2 - Interactions between the land surface and the atmosphere play a fundamental role in the weather and climate system. Here we present a comparison of summertime land-atmosphere coupling strength found in a subset of the ERA-Interim-driven European domain Coordinated Regional Climate Downscaling Experiment (EURO-CORDEX) model ensemble (1989 – 2008). Most of the regional climate models (RCMs) reproduce the overall soil moisture interannual variability, spatial patterns, and annual cycles of surface exchange fluxes for the different European climate zones suggested by the observational Global Land Evaporation Amsterdam Model (GLEAM) and FLUXNET data sets. However, some RCMs differ substantially from FLUXNET observations for some regions. The coupling strength is quantified by the correlation between the surface sensible and the latent heat flux, and by the correlation between the latent heat flux and 2 m temperature. The first correlation is compared to its estimate from the few available long-term European high-quality FLUXNET observations, and the latter to results from gridded GLEAM data. The RCM simulations agree with both observational datasets in the large-scale pattern characterized by strong coupling in southern Europe and weak coupling in northern Europe. However, in the transition zone from strong to weak coupling covering large parts of central Europe many of the RCMs tend to overestimate the coupling strength in comparison to both FLUXNET and GLEAM. The RCM ensemble spread is caused primarily by the different land surface models applied, and by the model-specific weather conditions resulting from different atmospheric parameterizations Y1 - 2017 U6 - https://doi.org/10.1002/2016JD025476 SN - 2169-8996 VL - 122 IS - 1 SP - 79 EP - 103 ER - TY - GEN A1 - Becker, Andreas A1 - Schaller, Eberhard A1 - Keuler, Klaus T1 - Continuous four-dimensional source attribution for the Berlin area during two days in July 1994. Part II: Sensitivy studies N2 - The multiple nested three-dimensional (3D) mesoscale Eulerian grid point model MM5 is directly coupled with a Lagrangian particle trajectory model in order to perform a four-dimensional source attribution for the area of Berlin based on the horizontal distribution of the import probability density (IPD). KW - LaMM5 KW - Source-receptor relationship KW - Euler-Lagrange model system KW - vertical mixing KW - FluMOB experiment Y1 - 2001 ER - TY - GEN A1 - Jacob, Daniela A1 - Keuler, Klaus A1 - Georgievski, Goran A1 - Radtke, Kai T1 - EURO-CORDEX: new high-resolution climate change projections for European impact research T2 - Regional Environmental Change N2 - A new high-resolution regional climate change ensemble has been established for Europe within the World Climate Research Program Coordinated Regional Downscaling Experiment (EURO-CORDEX) initiative. The first set of simulations with a horizontal resolution of 12.5 km was completed for the new emission scenarios RCP4.5 and RCP8.5 with more simulations expected to follow. The aim of this paper is to present this data set to the different communities active in regional climate modelling, impact assessment and adaptation. The EURO-CORDEX ensemble results have been compared to the SRES A1B simulation results achieved within the ENSEMBLES project. The large-scale patterns of changes in mean temperature and precipitation are similar in all three scenarios, but they differ in regional details, which can partly be related to the higher resolution in EURO-CORDEX. The results strengthen those obtained in ENSEMBLES, but need further investigations. The analysis of impact indices shows that for RCP8.5, there is a substantially larger change projected for temperature-based indices than for RCP4.5. The difference is less pronounced for precipitation-based indices. Two effects of the increased resolution can be regarded as an added value of regional climate simulations. Regional climate model simulations provide higher daily precipitation intensities, which are completely missing in the global climate model simulations, and they provide a significantly different climate change of daily precipitation intensities resulting in a smoother shift from weak to moderate and high intensities. Y1 - 2014 U6 - https://doi.org/10.1007/s10113-013-0499-2 SN - 1436-378X VL - 14 IS - 2 SP - 563 EP - 578 ER - TY - GEN A1 - Jacob, Daniela A1 - Keuler, Klaus A1 - Georgievski, Goran A1 - Radtke, Kai T1 - Erratum to: EURO-CORDEX: new high-resolution climate change projections for European impact research T2 - Regional Environmental Change Y1 - 2014 U6 - https://doi.org/10.1007/s10113-014-0587-y SN - 1436-378X N1 - weitere Autoren VL - 14 IS - 2 SP - 579 EP - 581 ER - TY - GEN A1 - Prein, Andreas A1 - Gobiet, Andreas A1 - Suklitsch, Martin A1 - Truhetz, Heimo A1 - Awan, N. K. A1 - Keuler, Klaus A1 - Georgievski, Goran T1 - Added value of convection permitting seasonal simulations T2 - Climate Dynamics Y1 - 2013 U6 - https://doi.org/10.1007/s00382-013-1744-6 VL - 41 SP - 2655 EP - 2677 ER - TY - GEN A1 - Kotlarski, Sven A1 - Keuler, Klaus A1 - Bøssing Christensen, Ole A1 - Colette, Augustin A1 - Déqué, Michel T1 - Regional climate modeling on European scales: A joint standard evaluation of the EURO-CORDEX RCM ensemble T2 - Geoscientific Model Development Y1 - 2014 U6 - https://doi.org/10.5194/gmd-7-1297-2014 N1 - 11 weitere Autoren IS - 7 SP - 1297 EP - 1333 ER - TY - GEN A1 - Panitz, Hans-Jürgen A1 - Dosio, Alessandro A1 - Büchner, Mathias A1 - Lüthi, Daniel A1 - Keuler, Klaus T1 - COSMO-CLM (CCLM) climate simulations over CORDEX Africa domain: Analysis of the ERA-Interim driven simulations at 0.44◦ and 0.22◦ resolution T2 - Climate Dynamics Y1 - 2014 U6 - https://doi.org/10.1007/s00382-013-1834-5 SN - 1432-0894 SN - 0930-7575 VL - 42 IS - 11-12 SP - 3015 EP - 3038 ER - TY - GEN A1 - Böhm, Uwe A1 - Keuler, Klaus A1 - Österle, Hermann A1 - Kücken, Martin A1 - Hauffe, Detlef T1 - Quality of a climate reconstruction for the CADSES regions T2 - Meteorologische Zeitschrift N2 - We used the regional climate model CCLM 4 to reconstruct the climate over the CADSES regions for the period 1961-2000. This most recent model version is currently still in a test phase. The simulation quality for this part of the entire simulation area is exemplarily analyzed by using a small but representative subset of model variables. Mean sea level pressure is chosen as an indicator for the behavior of the near-surface dynamics. Furthermore, the two regional variables 2 m temperature and precipitation are evaluated, which are of relevance for hydrological applications. For additional analyses to identify sources of uncertainty, we used soil moisture and cloudiness. Altogether, the accuracy of the simulation results can be judged as being in good agreement with the results of similar simulations by other regional climate models over Europe. Area-averaged monthly mean 2 m temperatures during winter show a cold bias of about -2 K. The simulated mean sea level pressure is with a bias of about 2 hPa slightly too high compared to the used reference data set. Although cloud cover evaluation hints at insufficiencies in the corresponding parameterization, further analyses are required to unambiguously identify the causes for this cold bias. During summer, higher 2 m temperatures linked to reduced precipitation are identified in nearly identical regions over southern and southeastern Europe. Further analyses of soil moisture evolution and cloud cover give evidence for a source of uncertainty in the surface hydrological scheme. Altogether, the detected differences do not exceed the typical ranges of uncertainty in comparable regional climate simulations over Europe. For input in hydrological applications, however, the uncertainties produced by the CCLM simulation described here have to be reduced in the medium term. N2 - Das Klima über den CADSES-Regionen wurde mit dem regionalen Klimamodell CCLM, Version 4.0 für den Zeitraum 1961-2000 rekonstruiert. Diese aktuellste Modellversion befindet sich gegenwärtig noch in einer Testphase. Die Qualität der Simulation für diesen Teil des Simulationsgebietes wird beispielhaft anhand einer kleinen, aber repräsentativen Teilmenge von Modellvariablen analysiert. Der Druck auf Meeresniveau wurde ausgewählt als Indikator für das Verhalten der bodennahen Dynamik. Weiterhin wurden die beiden Variablen 2 m Temperatur und Niederschlag als wichtige regionale Variablen für hydrologische Anwendungen bewertet. Für zusätzliche Analysen zur Identifizierung von Ungenauigkeitsquellen verwendeten wir die Bodenfeuchte und die Bewölkung. Insgesamt kann die Genauigkeit dieser Simulationsresultate als gut im Vergleich zu Ergebnissen von Simulationsläufen anderer regionaler Klimamodelle für Europa beurteilt werden. Gebietsmittel der monatlichen 2 m Temperaturen im Winter zeigen einen systematischen Fehler von etwa -2 K. Der simulierte Druck auf Meeresniveau ist mit einem systematischen Fehler von etwa 2 hPa etwas zu hoch im Vergleich zum verwendeten Referenzdatensatz. Obwohl die Evaluierung der Wolkendecke auf Unzulänglichkeiten in der entsprechenden Parametrisierung hinweist, sind weitere Analysen nötig, um die Ursachen für das systematisch zu kalte Modellverhalten eindeutig zu identifizieren. Im Sommer treten über nahezu identischen Regionen in Süd- und Südosteuropa höhere 2 m Temperaturen sowie geringere Niederschlägen auf. Weitere Analysen der zeitlichen Entwicklung der Bodenfeuchte und der Wolkenbedeckung geben Anhaltspunkte für eine Quelle von Ungenauigkeit im hydrologischen Teil des Bodenmodells. Insgesamt überschreiten die nachgewiesenen Unterschiede nicht die typischen Fehlerbereiche in vergleichbaren Klimasimulationen über Europa. Als Antrieb für hydrologische Anwendungen ist es allerdings mittelfristig erforderlich, die Ungenauigkeiten der hier beschriebenen CCLM-Simulation zu verringern. Y1 - 2008 U6 - https://doi.org/10.1127/0941-2948/2008/0318 SN - 1610-1227 VL - 17 IS - 4 SP - 477 EP - 485 ER - TY - GEN A1 - Feldmann, Hendrik A1 - Früh, Barbara A1 - Schädler, Gerd A1 - Panitz, Hans-Jürgen A1 - Keuler, Klaus A1 - Jacob, Daniela A1 - Lorenz, Peter T1 - Evaluation of the precipitation for south-western Germany from high resolution simulations with regional climate models T2 - Meteorologische Zeitschrift Y1 - 2008 U6 - https://doi.org/10.1127/0941-2948/2008/0295 SN - 1610-1227 VL - 17 IS - 4 SP - 455 EP - 465 ER - TY - GEN A1 - Walter, Andreas A1 - Keuler, Klaus A1 - Block, Alexander A1 - Knoche, Richard A1 - Block, Alexander A1 - Kotlarski, Sven A1 - Müller-Westermeier, Gerhard A1 - Rechid, Diana A1 - Ahrens, Wilfried T1 - A high resolution reference data set of german wind velocity 1951-2001 and comparison with regional climate model results T2 - Meteorologische Zeitschrift Y1 - 2006 U6 - https://doi.org/10.1127/0941-2948/2006/0162 SN - 1610-1227 VL - 15 IS - 6 SP - 585 EP - 596 ER - TY - GEN A1 - Böhm, Uwe A1 - Kücken, Martin A1 - Ahrens, Wilfried A1 - Block, Alexander A1 - Hauffe, Detlef A1 - Keuler, Klaus A1 - Rockel, Burkhardt A1 - Will, Andreas T1 - The Climate Version of LM: Brief Description and Long-Term Applications T2 - COSMO Newsletter Y1 - 2006 UR - http://www.cosmo-model.org/content/model/documentation/newsLetters/newsLetter06/newsLetter_06.pdf IS - 6 SP - 225 EP - 235 ER - TY - GEN A1 - Kotlarski, Sven A1 - Block, Alexander A1 - Böhm, Ursula A1 - Jacob, Daniela A1 - Keuler, Klaus A1 - Knoche, Richard A1 - Rechid, Diana A1 - Walter, Artur T1 - Regional Climate Model Simulations as Input for Hydrological Applications: Evaluation of Uncertainties T2 - Advances in Geoscience Y1 - 2005 U6 - https://doi.org/10.5194/adgeo-5-119-2005 IS - 5 SP - 119 EP - 125 ER - TY - GEN A1 - Vautard, Robert A1 - Gobiet, Andreas A1 - Keuler, Klaus T1 - The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project T2 - Climate Dynamics Y1 - 2013 U6 - https://doi.org/10.1007/s00382-013-1714-z SN - 1432-0894 SN - 0930-7575 N1 - weitere Autoren VL - 41 IS - 9-10 SP - 2555 EP - 2575 ER - TY - GEN A1 - Georgievski, Goran A1 - Keuler, Klaus A1 - Will, Andreas A1 - Radtke, Kai T1 - Evaluation of Central European and Eastern Alpine seasonal climate simulated with CCLM: double nesting vs. direct forcing techniques T2 - COSMO Newsletter Y1 - 2011 UR - www.cosmo-model.org/content/model/documentation/newsLetters/newsLetter11/newsLetter_11.pdf IS - 11 SP - 133 EP - 142 ER - TY - GEN A1 - Früh, Barbara A1 - Feldmann, Hendrik A1 - Panitz, Hans-Jürgen A1 - Schädler, Gerd A1 - Jacob, Daniela A1 - Lorenz, Peter A1 - Keuler, Klaus T1 - Determination of precipitation return values in complex terrain and their evaluation T2 - Journal of Climate Y1 - 2010 U6 - https://doi.org/10.1175/2009JCLI2685.1 SN - 1520-0442 VL - 23 IS - 9 SP - 2257 EP - 2274 ER - TY - CHAP A1 - Keuler, Klaus A1 - Block, Alexander ED - Bärring, Lars ED - Laprise, Rene T1 - High resolution climate change simulation for Central Europe T2 - Extended abstracts of a WMO/WCRP-sponsored Regional-Scale Climate Modelling Workshop, high-resolution climate modelling, assessment, added value and applications, Lund, Sweden, 29 March-2 April 2004 Y1 - 2005 SP - 106 EP - 107 PB - Lund University CY - Lund, Sweden ER - TY - CHAP A1 - Keuler, Klaus A1 - Block, Alexander A1 - Schaller, Eberhard ED - Bärring, Lars ED - Laprise, Rene T1 - Assessment of quality and uncertainty in regional climate simulations T2 - Extended abstracts of a WMO/WCRP-sponsored Regional-Scale Climate Modelling Workshop, high-resolution climate modelling, assessment, added value and applications, Lund, Sweden, 29 March-2 April 2004 Y1 - 2005 SP - 68 EP - 69 PB - Lund University CY - Lund, Sweden ER - TY - CHAP A1 - Radtke, Kai S. A1 - Keuler, Klaus ED - Rockel, Burkhardt ED - Bärring, Lars ED - Reckermann, Marcus T1 - Climate change in Europe simulated by the regional climate model COSMO-CLM T2 - 2nd International Lund RCM Workshop : 21st Century Challenges in Regional-scale Climate Modelling, Lund University, Sweden, 4-8 May 2008, workshop proceedings Y1 - 2009 SP - 56 EP - 57 PB - International BALTEX Secretariat CY - GKSS Forschungszentrum Geesthacht ER - TY - CHAP A1 - Keuler, Klaus A1 - Radtke, Kai S. A1 - Schaller, Eberhard ED - Rockel, Burkhardt ED - Bärring, Lars ED - Reckermann, Marcus T1 - Effect of internal variability on regional climate change projections T2 - 2nd International Lund RCM Workshop : 21st Century Challenges in Regional-scale Climate Modelling, Lund University, Sweden, 4-8 May 2008, workshop proceedings Y1 - 2009 SP - 132 EP - 133 PB - International BALTEX Secretariat CY - GKSS Forschungszentrum Geesthacht ER -