Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 15, 2401-2419, 2011
https://doi.org/10.5194/hess-15-2401-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
29 Jul 2011
Copula-based statistical refinement of precipitation in RCM simulations over complex terrain
P. Laux1, S. Vogl2, W. Qiu1, H. R. Knoche1, and H. Kunstmann1,2 1Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany
2University of Augsburg, Institute for Geography, Regional Climate and Hydrology, 86135 Augsburg, Germany
Abstract. This paper presents a new Copula-based method for further downscaling regional climate simulations. It is developed, applied and evaluated for selected stations in the alpine region of Germany. Apart from the common way to use Copulas to model the extreme values, a strategy is proposed which allows to model continuous time series. As the concept of Copulas requires independent and identically distributed (iid) random variables, meteorological fields are transformed using an ARMA-GARCH time series model. In this paper, we focus on the positive pairs of observed and modelled (RCM) precipitation. According to the empirical copulas, significant upper and lower tail dependence between observed and modelled precipitation can be observed. These dependence structures are further conditioned on the prevailing large-scale weather situation. Based on the derived theoretical Copula models, stochastic rainfall simulations are performed, finally allowing for bias corrected and locally refined RCM simulations.

Citation: Laux, P., Vogl, S., Qiu, W., Knoche, H. R., and Kunstmann, H.: Copula-based statistical refinement of precipitation in RCM simulations over complex terrain, Hydrol. Earth Syst. Sci., 15, 2401-2419, https://doi.org/10.5194/hess-15-2401-2011, 2011.
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