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Philipp A.,University of Augsburg | Bartholy J.,Eötvös Loránd University | Beck C.,University of Augsburg | Erpicum M.,University of Liège | And 16 more authors.
Physics and Chemistry of the Earth | Year: 2010

A new database of weather and circulation type catalogs is presented comprising 17 automated classification methods and five subjective classifications. It was compiled within COST Action 733 " Harmonisation and Applications of Weather Type Classifications for European regions" in order to evaluate different methods for weather and circulation type classification. This paper gives a technical description of the included methods using a new conceptual categorization for classification methods reflecting the strategy for the definition of types. Methods using predefined types include manual and threshold based classifications while methods producing types derived from the input data include those based on eigenvector techniques, leader algorithms and optimization algorithms. In order to allow direct comparisons between the methods, the circulation input data and the methods' configuration were harmonized for producing a subset of standard catalogs of the automated methods. The harmonization includes the data source, the climatic parameters used, the classification period as well as the spatial domain and the number of types. Frequency based characteristics of the resulting catalogs are presented, including variation of class sizes, persistence, seasonal and inter-annual variability as well as trends of the annual frequency time series. The methodological concept of the classifications is partly reflected by these properties of the resulting catalogs. It is shown that the types of subjective classifications compared to automated methods show higher persistence, inter-annual variation and long-term trends. Among the automated classifications optimization methods show a tendency for longer persistence and higher seasonal variation. However, it is also concluded that the distance metric used and the data preprocessing play at least an equally important role for the properties of the resulting classification compared to the algorithm used for type definition and assignment. © 2010.

Kreienkamp F.,Climate and Environment Consulting Potsdam GmbH | Spekat A.,Climate and Environment Consulting Potsdam GmbH | Enke W.,Climate and Environment Consulting Potsdam GmbH
Theoretical and Applied Climatology | Year: 2010

In this investigation, a circulation index was used which is capable of tracing blocked states of the hemispheric circulation which has a relevance for a mid-latitude window between 40° and 60°N and between 30°W and 30°E. Results with respect to the seasonality of blocking situations are presented. Additionally, it is shown to which degree the circulation conditions, as they are simulated by the ECHAM5-MPI/OM1 climate model, have a tendency to exhibit blocking. Finally, results are presented which indicate the developments in blocking if the index is applied to scenario runs of the model. © 2010 Springer-Verlag.

Routschek A.,TU Bergakademie Freiberg | Schmidt J.,TU Bergakademie Freiberg | Kreienkamp F.,Climate and Environment Consulting Potsdam GmbH
Catena | Year: 2014

This study investigates changes in erosion rates at high temporal and spatial resolution for three example catchments in West, North and East Saxony/Germany under climate change. The study is based on the A1B IPCC-scenario and model outputs of four models: ECHAM5-OPYC3 (general circulation model), WETTREG2010 (statistical downscaling climate model), METVER (agricultural model for calculation of daily initial soil moisture) and EROSION 3D as a process-based soil erosion model. Simulations were run for measured and projected single rainstorm events at a temporal resolution of 5. min. Soil loss was simulated for two future periods from 2041 to 2050 and 2091 to 2100, respectively. Results were compared to simulated soil loss based on 10. years of measured climate data from 1989 to 2007. Expected changes in land use, soil management due to changed crop rotation and shifted harvest date are taken into account as scenario studies.Outputs of the regional climate model show that the total number of rainstorms with intensities. ≥. 0.1. mm/min is decreasing in future while rainfall intensities are increasing. Periods of heavy rainstorms will mostly shift from summer to autumn. While the total amount of annual rainfall is decreasing and the duration of sunshine is strongly increasing, soils become drier. Dry periods will appear more often in late autumn.Results of the simulations with EROSION 3D quantify the impacts of climate change on erosion rates. Climate change will lead to a significant increase of soil loss by 2050 and a partial decrease by 2100. Not adapting soil management and land use will aggravate erosion rates.The impacts of land use, soil management and soil properties on soil erosion by water are higher than the effects of changed precipitation patterns. Current soil protection measures are suitable for soil conservation under conditions of a changed climate. © 2014 Elsevier B.V.

Kreienkamp F.,Climate and Environment Consulting Potsdam GmbH | Spekat A.,Climate and Environment Consulting Potsdam GmbH | Enke W.,Climate and Environment Consulting Potsdam GmbH
Atmosphere | Year: 2013

In this paper, the weather generator (WG) used by the empirical statistical downscaling method WETTREG (weather situation-based regionalization method (in German: WETTerlagen-basierte REGionalisierungsmethode)), is described. It belongs to the class of multi-site parametric models that aim at the representation of the spatial dependence among weather variables with conditioning on exogenous atmospheric predictors. The development of the WETTREG WG was motivated by (i) the requirement of climate impact modelers to obtain input data sets that are consistent and can be produced in a relatively economic way and (ii) the well-sustained hypothesis that large scale atmospheric features are well reproduced by climate models and can be used as a link to regional climate. The WG operates at daily temporal resolution. The conditioning factor is the temporal development of the frequency distribution of circulation patterns. Following a brief description of the strategy of classifying circulation patterns that have a strong link to regional climate, the bulk of this paper is devoted to a description of the WG itself. This includes aspects, such as the utilized building blocks, seasonality or the methodology with which a signature of climate change is imprinted onto the generated time series. Further attention is given to particularities of the WG's conditioning processes, as well as to extremes, areal representativity and the interface of WGs and user requirements. © 2013 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).

Spekat A.,Climate and Environment Consulting Potsdam GmbH | Kreienkamp F.,Climate and Environment Consulting Potsdam GmbH | Enke W.,Climate and Environment Consulting Potsdam GmbH
Physics and Chemistry of the Earth | Year: 2010

When carrying out an intercomparison of the methods participating in COST Action 733, particularly when looking at their applications-orientedness, investigating the discriminative power concerning target properties is an apt approach. CEC-TC, an alternative classification which builds the patterns from the impact up is presented in the context of such an intercomparison. That method is briefly presented and subsequently discussed in conjunction with other methods that participate in the COST Action. © 2010 Elsevier Ltd.

Kreienkamp F.,Climate and Environment Consulting Potsdam GmbH | Baumgart S.,Climate and Environment Consulting Potsdam GmbH | Spekat A.,Climate and Environment Consulting Potsdam GmbH | Enke W.,Climate and Environment Consulting Potsdam GmbH
Atmosphere | Year: 2011

When assessing the magnitude of climate signals in a regional scale, a host of optional approaches is feasible. This encompasses the use of regional climate models (RCM), nested into global climate models (GCM) for an area of interest as well as employing empirical statistical downscaling methods (ESD). In this context the question is addressed: Is an empirical statistical downscaling method capable of yielding results that are comparable to those by dynamical RCMs? Based on the presented ESD method, the comparison of RCM and ESD results show a high amount of agreement. In addition the empirical statistical downscaling can be applied directly to a GCM or a GCM-RCM cascade. The paper aims at comparing the consequences of employing various CGM-RCM-ESD combinations on the derived future changes of temperature and precipitation. This adds to the insight on the scale dependency of downscaling strategies. Results for one GCM with several scenario runs driving several RCMs with and without subsequent empirical statistical downscaling are presented. It is shown that there are only small differences between using the GCM results directly or as a GCM-RCM-ESD cascade. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

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