Willett et al. (2010)
Also: Willett et al. 2010
A comparison of large scale changes in surface humidity over land in observations and CMIP3 general circulation models
Willett, K. M., Jones, P. D., Thorne, P. W., & Gillett, N. P. (2010). A comparison of large scale changes in surface humidity over land in observations and CMIP general circulation model Environmental Research Letters 5 (2), 025210. Link to PDF
doi: 10.1088/1748-9326/5/2/025210
References
All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.