TY  - JOUR
A1  - Ibebuchi, Chibuike Chiedozie
T1  - On the representation of atmospheric circulation modes in regional climate models over Western Europe
JF  - International Journal of Climatology
N2  - Atmospheric circulation is a key driver of climate variability, and the representation of atmospheric circulation modes in regional climate models (RCMs) can enhance the credibility of regional climate projections. This study examines the representation of large‐scale atmospheric circulation modes in Coupled Model Inter‐comparison Project phase 5 RCMs once driven by ERA‐Interim, and by two general circulation models (GCMs). The study region is Western Europe and the circulation modes are classified using the Promax rotated T‐mode principal component analysis. The results indicate that the RCMs can replicate the classified atmospheric modes as obtained from ERA5 reanalysis, though with biases dependent on the data providing the lateral boundary condition and the choice of RCM. When the boundary condition is provided by ERA‐Interim that is more consistent with observations, the simulated map types and the associating time series match well with their counterparts from ERA5. Further, on average, the multi‐model ensemble mean of the analysed RCMs, driven by ERA‐Interim, indicated a slight improvement in the representation of the modes obtained from ERA5. Conversely, when the RCMs are driven by the GCMs that are models without assimilation of observational data, the representation of the atmospheric modes, as obtained from ERA5, is relatively less accurate compared to when the RCMs are driven by ERA‐Interim. This suggests that the biases stem from the GCMs. On average, the representation of the modes was not improved in the multi‐model ensemble mean of the five analysed RCMs driven by either of the GCMs. However, when the best‐performed RCMs were selected on average the ensemble mean indicated a slight improvement. Moreover, the presence of the North Atlantic Oscillation (NAO) in the simulated modes depends also on the lateral boundary conditions. The relationship between the modes and the NAO was replicated only when the RCMs were driven by reanalysis. The results indicate that the forcing model is the main factor in reproducing the atmospheric circulation.
KW  - general circulation model
KW  - large‐scale atmospheric circulation modes
KW  - multi‐model ensemble
KW  - regional climate model
KW  - Western Europe
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312424
VL  - 43
IS  - 1
SP  - 668
EP  - 682
ER  - 
TY  - THES
A1  - Paxian, Andreas
T1  - Future changes in climate means and extremes in the Mediterranean region deduced from a regional climate model
T1  - Zukünftige Veränderungen von Klimamittelwerten und -extremwerten im Mittelmeerraum abgeleitet von einem regionalen Klimamodell
N2  - The Mediterranean area reveals a strong vulnerability to future climate change due to a high exposure to projected impacts and a low capacity for adaptation highlighting the need for robust regional or local climate change projections, especially for extreme events strongly affecting the Mediterranean environment. The prevailing study investigates two major topics of the Mediterranean climate variability: the analysis of dynamical downscaling of present-day and future temperature and precipitation means and extremes from global to regional scale and the comprehensive investigation of temperature and rainfall extremes including the estimation of uncertainties and the comparison of different statistical methods for precipitation extremes. For these investigations, several observational datasets of CRU, E-OBS and original stations are used as well as ensemble simulations of the regional climate model REMO driven by the coupled global general circulation model ECHAM5/MPI-OM and applying future greenhouse gas (GHG) emission and land degradation scenarios.
N2  - Der Mittelmeerraum weist eine starke Vulnerabilität gegenüber dem zukünftigen Klimawandel auf, da für diese Region starke klimatische Auswirkungen vorhergesagt werden, aber nur eine geringe Anpassungsfähigkeit besteht. Daher werden präzise Vorhersagen des regionalen oder lokalen Klimawandels benötigt, v.a. für Extremereignisse, welche den Mittelmeer-Lebensraum stark beeinträchtigen. Die vorliegende Studie untersucht zwei Hauptaspekte der Klimavariabilität im Mittelmeerraum: Zum Einen wird das dynamische Downscaling gegenwärtiger und zukünftiger Mittelwerte und Extremereignisse von Temperatur und Niederschlag von der globalen zur regionalen Skala analysiert. Zum Anderen wird eine umfassende Untersuchung von Temperatur- und Niederschlagsextremen samt Unsicherheitsabschätzung und Vergleich unterschiedlicher statistischer Methoden zur Bestimmung von Niederschlagsextremen durchgeführt. Für diese Untersuchungen stehen verschiedene Beobachtungsdaten von CRU, E-OBS und Messstationen sowie Ensemble-Simulationen des regionalen Klimamodells REMO zur Verfügung, das vom gekoppelten globalen “General Circulation Model” ECHAM5/MPI-OM angetrieben wird und zukünftige Treibhausgasemissions- und Landnutzungsänderungs-Szenarien verwendet.
KW  - Mittelmeerraum
KW  - Klima
KW  - Klimaänderung
KW  - Temperatur
KW  - Modell
KW  - Niederschlag
KW  - Klimaschwankung
KW  - Klimamodellierung
KW  - regionales Klimamodell
KW  - Mittelmeer
KW  - Modellierung
KW  - Extremwertstatistik
KW  - climate modelling
KW  - regional climate model
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-72155
ER  -