The control integration with the CM3-Model, in which the atmospheric forcing is kept constant (CTL). The IPCC Data Distribution Centre (DDC) distributes data of a 240-year period according to the length of the climate change experiments (the greenhouse gas and the all anthropogenic forcing runs) available from Hadley Centre. The dates in the control run are arbitrary, really, since there is no climate change. 2091 corresponds to 1859. To obtain the control year for a given anomaly year, subtract 232. The anomaly runs start on 1st Dec 1859, and the relevant part of the control run on 1st Dec 2091. These data represent monthly averaged surface values of selected variables for the IPCC-Data Distribution Centre. (see also http://www.ipcc-data.org/ )