ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-7-17261-2007 Technical Note: Description and assessment of a nudged version of the new dynamics Unified Model Telford P. J. 1 Braesicke P. 1 Morgenstern O. 1 Pyle J. A. 1 University of Cambridge, Cambridge NCAS-Climate, UK 27 11 2007 7 6 17261 17297 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/7/17261/2007/acpd-7-17261-2007.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/7/17261/2007/acpd-7-17261-2007.pdf

We present a "nudged" version of the Met Office general circulation model, the Unified Model. We constrain this global climate model using ERA-40 reanalysis data with the aim of reproducing the observed "weather" over a year from September 1999. Quantitative assessments are made of its performance, focussing on dynamical aspects of nudging and demonstrating that the "weather" is well simulated.

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