Climatic Change in the Tohoku District (II)

[摘要] In the third chapter, we try the stochastic analysis and forecasting of the mean August temperature at Miyako in the Tohoku district. That is, the original data are so complicated that they are separated into six simple components: secular trend m(t), three harmonics with 7.4-year, 13-year and 11.4-year periods, V7.4(t), V13(t) and V11.4(t), and two fluctuations with two cyclic periodicities, U10(t) and U2(t). Each component is precisely analysed and composite values are forecasted with the precision expressed by probability.In the fourth chapter, the periodicities picked up in the second chapter are synoptically analysed. Namely, in view of synoptic climatology, we recognize the significant difference between the patterns of August temperature anomalies in the maximum years and in the minimum years of the V7.4(t) in which the V13(t) is under consideration. Such differences are found in the upper westerly currents at Tateno and in the paths of typhoons in August. Lastly, using the cross correlation coefficients, we investigate on the lag relation between Wolf's sun-spot numbers and the residual temperature series where two harmonics, V7.4(t) and V13(t), are eliminated.

[学科分类] 大气科学