Editing IPCC:Wg1:Chapter:Chapter-1-comments (section)

==== 1.5.3.3 From Global to Regional Models ====

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The need for accurate climate information at the regional scale is increasing (Section 10.1). High-resolution global climate models, such as those taking part in HighResMIP, provide more detailed information at the regional scale ( [[#Roberts--2018|Roberts et al., 2018]] ). However, due to the large computational resources required by these models, only a limited number of simulations per model are available. In addition to CMIP global models, regional information can be derived using regional climate models (RCMs) and downscaling techniques, presented in [https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-10 Chapter 10] and the Atlas. RCMs are dynamical models, similar to GCMs, that simulate a limited region and are forced with boudary conditions from a global simulation, often correcting for biases (Section 10.3, Cross-Chapter Box 10.2 and Annex II). This approach allows the use of a higher resolution within the chosen domain, and thus better represents important drivers of regional climate such as mountain ranges, land management and urban effects. RCMs resolving atmospheric convection explicitly are now included in intercomparisons ( [[#Coppola--2020|Coppola et al., 2020]] ) and are used in Chapters 10, 11 and 12. Other approaches, such as statistical downscaling, are also used to generate regional climate projections (Section 10.3; [[#Maraun--2018|Maraun and Widmann, 2018]] ).

The number of climate centres or consortia that carry out global climate simulations and projections has grown from 11 in the first CMIP to 19 in CMIP5 and 28 for CMIP6 ( [[#1.5.4.2|Section 1.5.4.2]] and Annex II). Regional climate models participating in the Coordinated Regional Downscaling Experiment (CORDEX) are more diverse than the global ESMs ( [[#1.5.4.3|Section 1.5.4.3]] and Annex II) and engage an even wider international community (Figure 1.20).

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'''Figure 1.20 |''' '''World map showing the increased diversity of modelling centres contributing to CMIP and CORDEX.''' Climate models are often developed by international consortia. One such consortium, EC-Earth, is shown as an example under the label '''8 EU Cities''' (involving SMHI, Sweden; KNMI, The Netherlands; DMI, Denmark; AEMET, Spain; Met Éireann, Ireland; CNR‐ISAC, Italy; Instituto de Meteorologia, Portugal; and FMI, Finland). There are too many such collaborations to display all of them on this map. More complete information about institutions contributing to CORDEX and CMIP6 is found in Annex II.
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