112 Modellingthe climate
2 Richardson, L. F. 1922. Weather Prediction by Numerical Processes.
Cambridge: Cambridge University Press. Reprinted by Dover, 1965.
3 For more details see, for instance, Houghton, The Physics of Atmo-
spheres.
4 For more detail see:
Chapter 13 in Houghton,The Physics of Atmospheres.
Palmer, T. N. 1993. A nonlinear perspective on climate change.Weather,
48 , pp. 314–26.
Palmer, T. N. 1999.Journal of Climatology, 12 , pp. 575–91.
5 An equation such asy=ax+bis linear; a plot ofyagainstxis a straight
line. Examples of non-linear equationsarey=ax^2 +bory+xy=ax+b;
plots ofyagainstxfor these equations would not be straight lines. In
the case of the pendulum,the equations describing themotion are only
approximately linear for very small angles from the vertical where the
sine of the angle is approximately equal to the angle; at larger angles
this approximation becomes much less accurate and the equations are
non-linear.
6 More detail in McAvaney, B. J.et al. 2001. In Houghton, J. T., Ding, Y.,
Griggs, D. J., Noguer, M., van der Linden, P. J., Dai, X., Maskell, K., Johnson,
C. A. (eds.)Climate Change 2001: The Scientific Basis.Contribution of
Working Group I to the Third Assessment Report of the Intergovernmen-
tal Panel on Climate Change. Cambridge: Cambridge University Press,
Chapter 8.
7 See, for instance:
Cane, M. A.1992. In Trenberth, K. E. (ed.)Climate SystemModelling.
Cambridge: Cambridge University Press, pp. 583–616.
McAvaneyet al., Chapter 8, in Houghton,Climate Change 2001.
Federov, A. V.et al. 2003. How predictable is El Ni ̃no?Bulletin of the
American Meteorological Society, 84 , pp. 911–919.
8 Folland, C. K., Owen, J., Ward, M. N., Colman, A. 1991. Prediction of
seasonal rainfall in the Sahel region using empirical and dynamical methods.
Journal of Forecasting, 10 , pp. 21–56.
9 Information from Folland, C., Hadley Centre, UK.
10 Xue, Y. 1997. Biosphericfeedback on regional climate in tropical north
Africa.Quarterly Journal of the Royal Meteorological Society, 123 , pp.
1483–1515.
11 Associated with water vapour feedback is alsolapse rate feedbackwhich
occurs because, associated with changes of temperature and water vapour
content in the troposphere, are changes in the average lapse rate (the rate of
fall of temperature with height). Such changes leadto this further feedback,
which is generally much smaller in magnitude than water vapour feedback
but of the opposite sign, i.e. negative instead of positive. Frequently, when
overall values for water vapour feedback are quoted the lapse rate feedback
has been included. For more details see Houghton,The Physics of Atmo-
spheres.