倒春寒的划分和预报服务探讨

本文利用预报区域1960～1995年春季逐日气象资料，分析得到了倒春寒天气的客观划分标准、气候特点、主要影响系统及其形势特征。采用较新特色的折扣回归模型，建立了三、四月份各旬倒春寒的集成预报方程；利用短期预报资料，研制出若干预报判据和消空指标，建立了短期预报回归方程，并编制出具有一定特色的预报服务系统。经1997年实际应用，倒春寒天气的预报准确率在经验预报的基础上提高20％左右。

A STUDY ON DIVISION OF LATE SPRING COLD AND ITS FORECASTING

The objective division for Late Spring Cold(LSC)weather is built using thedaily data of springs from l960 to 1995 in the associated area in this paper. The climatic char-acteristics of LSC and the pattern of influential weather systems have also been studied. Anadvanced discount regressive model has been taken here to build ensemble prediction equa-tions for lO-day forecasting of LSC in March or in April. By using short range forcasting da-ta,some forecasting criteria and emptying indices have been given to estiblish the regressiveequations. A forecasting service system with certain distinguishing features is constructed,which had been put into pratical use for forecasting the LSC of 1997- The rate of predictionaccuracy has been improved about 20% with comparison of empirical forecasting,which is ex-actly what we expected.