Important notes regarding the 'nat' simulation:

• The surface roughness due to vegetation cover was incorrectly set to present-day, rather than pre-industrial, values during this simulation. This results in a step-change between this 'nat' simulation and the 'all' simulation in 1750 (because the vegetation roughness is changed to pre-industrial cover at the start of the 'all' simulation). Simon Tett will be calculating some correction fields for each variable, which can be applied to the 'nat' simulation data to remove the vegetation error effects.
• The data files run from 1492-1999, but in SO&P we are using data from 1500-1999 only.