To Predict CO2 Concentration
§Add one additional prognostic variable, CO2
qOnly advection and diffusion in the model
qSource/Sink from the surface
qNo feedback between the integrated CO2 and radiative properties in SPEEDY
qNo chemical processes
NOT well-known
Predict the atmospheric concentration of CO2 
when there is only source of fossil fuel emission
In order to do a data assimilation of CO2, I need a model which has a CO2 as a prognostic variable.  So, I added one prognostic variable which has only the process of advection and diffusion.  Like the equation that Dr. Inez Fung introduced, I didnÕt consider any chemical processes and there is no feedback between the integrated CO2 and radiative properties in SPEEDY.  And the source of CO2 is only from the surface.  Here, IÕll just show you the result of CO2 concentration when there is only the forcing from fossil fuel emission.