Studies on Mass-conservation in Atmospheric Spectral Model
大气谱模式中质量守恒格式的研究

The global spectral models are widely used over the world in the operational numerical weather prediction,atmospheric dynamics and climate simulations.However,there is a problem that nowday spectral models cannot preserve the total atmospheric mass conservation. The problem is caused by using the natural logarithm of surface pressure, Inps, rather than pressure, ps, as one of the spectral represented prognostic variable. Use of p, as prognostic variable does not violate the total mass conervation, but it introduces a much more substantial aliasing erros in the calculation of the pressure gradient. In this paper, we work on the mass-conservation in atmospheric spectral model. Based on the past works, an alternative method of using specific volume,a,as themodynamic variable is proposed.This method, surface pressure, ps, as a prognostic varibable, and it does not cause difficulty in the calculation of the pressure gradient. The computational results show that the forecast quality is slightly improved.