PowerPoint Presentation

Problem of Mass Conservation

§Imperfect conservation of mass (spectral dynamics)

§Empirical correction

qSum up CO2 forcing from the whole surface

üA=·(CO2 forcing) for every timestep (40 min)

qAccumulate total mass of CO2 in the simulation: B

üB= · (CO2 concentration) over all grids for every timestep

qMultiplying the ratio of A/B to every grid

üA>B (loss of mass in SPEEDY)


	During this work, I found that SPEEDY does not conserve the mass perfectly, which results from the numerical problem of spectral dynamics. So, I just corrected this problem empirically. Since I know total amount of source from the surface, I multiplied the ratio of total mass that the model should have to the total mass that the model has into every gridpoint.