Gutiérrez Llorente, José Manuel

Herrera García, Sixto

Jury, Martin W.

English

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Geophysical Research AbstractsVol. 19, EGU2017-13764, 2017EGU General Assembly 2017© Author(s) 2017. CC Attribution 3.0 License.On the representation of atmospheric blocking in EURO-CORDEXcontrol runsMartin W. Jury (1), Sixto García (2), and José M. Gutiérrez (3)(1) University of Graz, Wegener Center for Climate and Global Change, Graz, Austria(martinwolfgang.jury@edu.uni-graz.at), (2) Grupo de Meteorología. Departamento Matematica Aplicada y Ciencias de laComputación, Universidad de Cantabria, Santander, Spain, (3) Grupo de Meteorología. Instituto de Física de Cantabria.CSIC-Universidad de Cantabria, Santander, SpainWhile regional climate models (RCMs) have been shown to yield improved projections, due to better representa-tions of orography and higher resolved scales, impacts on mesoscale phenomena like atmospheric blocking havebeen hardly addressed. In this study we clarify if the EURO-CORDEX domain is large enough to allow the RCMsto significantly amplify the blocking representation in reference to the underlying driving data.Therefore, we analyzed blocking accompanying anomalies in temperature near the surface (TAS) and pre-cipitation rate (PR) for a set of RCMs. 5 RCMs stem from the ensemble of EURO-CORDEX control runs, while3 RCMs are WRF models with different nudging realizations, all of them are driven by ERA-Interim. The usedblocking detection method detects blockings by localizing high pressure systems between 55◦N and 65◦N withthe use of geopotential height gradients on the 500 hPa level (Z500), and was applied to ERA-Interim and thementioned RCM data between 1981 and 2010. Detected blockings centers were spatially attributed to threesectors, which have been shown to display distinctive impacts on TAS and PR during blocking episodes. As areference for TAS and PR we used 86 weather stations across Europe from the ECA&D dataset.Our results indicate, that little improvement can be expected in the representation of Z500 fields by theRCMs. Most of them show less blocking than the driving data, while blocking representation was most inagreement with the driving data for RCMs that have been strongly conditioned to the driving data. Further, in ouridealized setting the RCMs were not able to reproduce the anomalies for TAS connected to blocking. Moreover,using the blocking index of the driving data could be considered correct, because the representation of TAS andPR for falsely detected blocking and non-blocking days in the RCMs did not deviate strongly.

On the representation of atmospheric blocking in EURO-CORDEX 
control runs

https://repositorio.unican.es/xmlui/bitstream/10902/13022/3/OnTheRepresentation.pdf

On the representation of atmospheric blocking in EURO-CORDEX control runs

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