With the mesoscale model being used as the dynamical frame, and coupled with the cloud model of explicit scheme, a numerical simulation is conducted on the macro parameters of cloud fields, water vapour of cloud and size-distribution of the spectrum of cloud particles, based on which the application of cloud model in aviation is also investigated.

The Singular Spectrum Analysis method,especially on the fundamental property of identifying the oscillatory compo-nents,is described.It is applied to a 30-year surface temperature series of east-southem china with a windows length of 100 days.Two main low-frequency oscillations with period of 35-40day and about 20 days are found to be robust,accounting for about 90% of total variance in the relevant frequency band.