The Initial Field Constructions for Numerical Weather Prediction in the Low Latitudinal Regions by a New Mixed Type Autocorrelation Function

Abstract

A univariate statistical scheme for the analysis of geopotential height fields has been developed based upon optimum interpolation. The data archived from a set of subjective analyses were used to compute the required correlation functions. The computed height autocorrelation functions were fitted by an appropriate function which would definitely reftect the charac teristics of the statistical structure in the low latitudinal regions. Rather than representing the model by the negative squared exponential form proposed by Gaudin (1963), a representation consisting of a polynomial exponential func tion was used to fully trace the finer structure of the statistical quantities.The analyzed geopotential height fields were obtained through the compu tation of the geopotential height autocorrelation model. As a measurement of accuracy, this scheme has been tested at target stations. The root mean squares between the analysed data and those obtained from radiosonde data have been carried out to verify its performance as well.