Model tuning refers to the process of adjusting and refining a model to make it perform better. It involves changing the settings or parameters of a model to improve its accuracy and effectiveness in solving a specific problem. Full definition
The basic thrust of the article is that climate modeling groups are making significant efforts to increase the transparency and availability of model tuning processes for the next round of intercomparisons (CMIP6). (realclimate.org)
This an accepted method of model tuning called inversion; however, inversion can produce non unique solutions. (judithcurry.com)
To establish the range of sea level rise resulting from the choice of different SRES scenarios, results for thermal expansion and land - ice change from simple models tuned to several AOGCMs are used (as in Section F. 3 for temperature). (ipcc.ch)