A SIMILARITY SCHEME FOR QUANTITATIVE FORECAST OF PRECIPITATION OF TYPHOONS

A quantitative scheme is put forward in our work of forecasting the storm rainfall of typhoons for specific sites. Using the initial parameters, weather situations and physical quantities as well as numerical weather prediction products, the scheme constructs multivariate, objective and similarity criteria for environmental factors for the time between the current and forthcoming moment within the domain of forecast. Through defining a non-linear similarity index, this work presents a comprehensive assessment of the similarity between historical samples of typhoons and those being forecast in terms of continuous dynamic states under the multivariate criteria in order to identify similar samples. The historical rainfall records of the similar samples are used to run weighted summarization of the similarity index to determine site-specific and quantitative forecasts of future typhoon rainfall. Samples resembling the typhoon being forecast are selected by defining a non-linear similarity index composed of multiple criteria. Trial tests have demonstrated that this scheme has positive prediction skill.