Editing HadCM3 (section)

{{short description|Coupled climate model}}
{{Use dmy dates|date=September 2022}}

'''HadCM3''' (abbreviation for ''Hadley Centre Coupled Model, version 3'') is a coupled atmosphere-ocean [[general circulation model]] (AOGCM) developed at the [[Hadley Centre]] in the United Kingdom.<ref>{{cite journal |last=Gordon |first=C. |author2=Cooper, C. |author3=Senior, C.A. |author4=Banks, H. |author5=Gregory, J.M. |author6=Johns, T.C. |author7=Mitchell, J.F.B. |author7-link=John F. B. Mitchell |author8=Wood, R.A. |year=2000 |title=The simulation of SST, sea ice extents and ocean heat transports in a version of the Hadley Centre coupled model without flux adjustments |journal=Climate Dynamics |volume=16 |pages=147–168 |url=http://www.met-office.gov.uk/research/hadleycentre/models/gordon00/index.html |archiveurl=https://web.archive.org/web/20011114021921/http://www.met-office.gov.uk/research/hadleycentre/models/gordon00/index.html |archivedate=14 November 2001 |doi=10.1007/s003820050010 |issue=2–3 |bibcode=2000ClDy...16..147G |s2cid=128588784 |url-access=subscription }}</ref><ref>{{cite journal |last=Pope |author-link=Vicky Pope |first=V.D. |author2=Gallani, M.L. |author3=Rowntree, P.R. |author4=Stratton, R.A.  |year=2000 |title=The impact of new physical parameterizations in the Hadley Centre climate model – HadAM3 |journal=Climate Dynamics |volume=16 |pages=123–146 |url=http://www.met-office.gov.uk/research/hadleycentre/models/pope00/index.html |archiveurl=https://web.archive.org/web/20010707000718/http://www.met-office.gov.uk/research/hadleycentre/models/pope00/index.html |archivedate=7 July 2001 |doi=10.1007/s003820050009 |issue=2–3 |bibcode=2000ClDy...16..123P |s2cid=129848975 |url-access=subscription }}</ref><ref>{{cite journal |last=Collins |first=M. |author2=Tett, S.F.B. |author3=Cooper, C.  |year=2001 |title=The internal climate variability of HadCM3, a version of the Hadley Centre coupled model without flux adjustments |journal=Climate Dynamics |volume=17 |issue=1 |pages=61–81 |doi=10.1007/s003820000094 |bibcode=2001ClDy...17...61C |s2cid=129349364 }}</ref>  It was one of the major models used in the [[IPCC Third Assessment Report]] in 2001.

Unlike earlier AOGCMs at the Hadley Centre and elsewhere (including its predecessor HadCM2), HadCM3 does not need flux adjustment (additional "artificial" heat and freshwater fluxes at the ocean surface) to produce a good simulation. The higher ocean resolution of HadCM3 is a major factor in this; other factors include a good match between the atmospheric and oceanic components; and an improved ocean mixing scheme (Gent and McWilliams). HadCM3 has been run to produce simulations for periods of over a thousand years, showing little drift in its surface climate.

HadCM3 is composed of two components: the atmospheric model HadAM3 and the ocean model HadOM3 (which includes a sea ice model). Simulations use a [[360-day calendar]], where each month is 30 days.