Dear Canute,

These links will be very useful to you.

http://onlinelibrary.wiley.com/doi/10.1002/joc.4334/abstract

http://download.springer.com/static/pdf/970/art%253A10.1007%252Fs00382-014-2418-8.pdf?originUrl=http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs00382-014-2418-8&token2=exp=1470745470~acl=%2Fstatic%2Fpdf%2F970%2Fart%25253A10.1007%25252Fs00382-014-2418-8.pdf%3ForiginUrl%3Dhttp%253A%252F%252Flink.springer.com%252Farticle%252F10.1007%252Fs00382-014-2418-8*~hmac=ac9e72e5035e1a9cf7f1b0ce3b6ed9032787b71976ee83977956e123b72e2c0f

You can also read this book on Validation of Weather Generator outputs.

http://ukclimateprojections.metoffice.gov.uk/media.jsp?mediaid=87941&filetype=pdf

I hope this helps. All the best !

Formerly climatology was regional, as defined by Koppen and others, notably Trewartha.

The paper by Belda et Al (2014) shows the climate regions of the world (except Antarctica) for two periods, 1901-1931 and 1975-2005. Between the two periods separated by 75 years.

Climate classification revisited from Köppen to Trewartha, Belda, M. et al, Climate Research, 2014

http://www.int-res.com/articles/cr_oa/c059p001.pdf

Belda et al is one of several papers describing climate regions using temperature and precipitation data from the CRU.

The question might be, how much would the Koppen-Trewartha regions change between the states estimated using CRU data compared to states using projections from models.

The problem would be to resolve in your own mind whether you would be prepared equally to present either positive or negative results.

Starting from past data you can produce a "prediction" of present. You can validate them using present data (if available). If prediction is correct, you can use that rules to produce "near future" prediction.

For details see following link

http://link.springer.com/article/10.1007%2Fs10661-012-2951-z

Thanks Francesco

I used the historical and GCM derived climate data to calculate R2 (R square), but i am told that R2 is not a good method to validate the GCM derived data, what are other statistics can i use to ascertain that the GCMs are predicting well the observed climate?