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Does dynamical downscaling introduce novel information in climate model simulations of precipitation change over a complex topography region?
Author(s) -
Tselioudis George,
Douvis Costas,
Zerefos Christos
Publication year - 2012
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.2360
Subject(s) - climatology , precipitation , downscaling , orography , orographic lift , environmental science , forcing (mathematics) , climate model , gcm transcription factors , climate change , atmospheric sciences , general circulation model , geology , meteorology , geography , oceanography
Current climate and future climate‐warming runs with the RegCM Regional Climate Model (RCM) at 50 and 11 km‐resolutions forced by the ECHAM GCM are used to examine whether the increased resolution of the RCM introduces novel information in the precipitation field when the models are run for the mountainous region of the Hellenic peninsula. The model results are inter‐compared with the resolution of the RCM output degraded to match that of the GCM, and it is found that in both the present and future climate runs the regional models produce more precipitation than the forcing GCM. At the same time, the RCM runs produce increases in precipitation with climate warming even though they are forced with a GCM that shows no precipitation change in the region. The additional precipitation is mostly concentrated over the mountain ranges, where orographic precipitation formation is expected to be a dominant mechanism. It is found that, when examined at the same resolution, the elevation heights of the GCM are lower than those of the averaged RCM in the areas of the main mountain ranges. It is also found that the majority of the difference in precipitation between the RCM and the GCM can be explained by their difference in topographic height. The study results indicate that, in complex topography regions, GCM predictions of precipitation change with climate warming may be dry biased due to the GCM smoothing of the regional topography. Copyright © 2011 Royal Meteorological Society