Brulhet, J. and Texier, D. and Noblet, N. and Paillard, D. and Degnan, P. and Becker, A. and Cortes, A. and Pinedo, P. and Recreo Jiménez, Fernando and Agüero Prieto, Almudena and Ruiz García, Casilda and Lomba Falcón, Luis and Torres Pérez-Hidalgo, Trinidad José and Lucini, Manuel and Ortiz Menéndez, José Eugenio and Marbaix, P. and Kageyama, M. and Lunt, D.
Deliverable D8a: Development of the rule-based downscaling methodology for BIOCLIM Workpackage 3. Work Package 3, Simulation of the future evolution of the biosphere system using the hierarchical strategy. Modelling Sequential Biosphere Systems under Climate Change for Radioactive Waste Disposal (BIOCLIM).
Monografía (Project Report).
E.T.S.I. Minas (UPM), Francia.
One of the tasks of BIOCLIM WP3 was to develop
a rule-based approach for downscaling from the
MoBidiC model of intermediate complexity (see
Ref.1) in order to provide consistent estimates of
monthly temperature and precipitation for the specific
regions of interest to BIOCLIM (Central Spain, Central
England and Northeast France, together with Germany
and the Czech Republic). Such an approach has been
developed and used in a previous study funded by Nirex
to downscale output from an earlier version of this
climate model covering the Northern Hemisphere only,
LLN 2-D NH, to Central England, and evaluated using
palaeoclimate proxy data and General Circulation
Model (GCM) output for this region. This previous study
[Ref.2] provides the starting point for the BIOCLIM
A statistical downscaling methodology has been
developed by Philippe Marbaix of CEA/LSCE for use
with the second climate model of intermediate
complexity used in BIOCLIM – CLIMBER-GREMLINS
(see Ref.1). This statistical methodology is described
in Deliverable D8b [Ref.3]. Inter-comparisons of all the
downscaling methodologies used in BIOCLIM (including
the dynamical methods applied in WP2 – see Ref.4 and
Ref.5) are discussed in Deliverable D10-12 [Ref.6].
The rule-based methodology assigns climate states or
classes to a point on the time continuum of a region
according to a combination of simple threshold
values which can be determined from the coarse
scale climate model. Once climate states or classes
have been defined, monthly temperature and
precipitation climatologies are constructed using
analogue stations identified from a data base of
present-day climate observations. The most appropriate
climate classification for BIOCLIM purposes is the
Køppen/Trewartha scheme (Ref.7 ; see Appendix 1).
This scheme has the advantage of being empirical, but
only requires monthly averages of temperature and
precipitation as input variables.