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24 March 1987, Volume 6 Issue 1   
  • ON SOME VERTICAL INTERPOLATION SCHEMES AND NEW FORM OF HYDROSTATIC EQUATION
  • Qian Yongfu
  • 1987 Vol. 6 (1): 21-30. 
  • Abstract ( ) PDF (658KB) ( )
  • The accuracy of vertical interpolation of the initial data in numerical prediction is one of widely concerned problems.Some vertical interpolation schemes are checked in this paper by using given vertical profiles of both the temperature and the geopotential height fields.those schemes are the Lagrange method,the local linear interpolation method and the local spline method which is suggested in this paper by the author. Tests indicate that all of those three methods have quite good accuracy when the vertical resolution is high, for example, the number of vertical levels is ten or more, none of them can give satisfactory results when the vertical resolution is very low, for instance, the number of the levels is three or less. Generally speaking, the vertical resolution with 5 or more levels will obtain quite adequate interpolation accuracy. It is also suggested that a new form of the hydrostatic equation which is given in this paper should be used in order to keep the initial accuracy of the interpolated data. The new form keeps the balance between the temperature and the geopotential height fields in the vertical direction.