摘要
本文提出用年旱涝指数来研究气候变化规律,具有一定的物理意义及代表性。对北京地区旱涝变化规律分析表明:有5年及22年周期变化规律。 在旱涝预测方面,本文还提出一种新的时间序列预测方法——周期模式法,它较之传统的方差分析方法具有较多的优越性。用它对北京地区年度旱涝趋势作预测试验。
Water supplement is .very important in Beijing where drought has frequently occurred since the 1960s. The climatic prospect about drought or flood is studied in this paper. The-study will focus the attention on three problems: first, how is the climate situation about dryness and wetness described? Second, how do they vary with time? Third, which method will be better for forecasting them?
The yearly dryness/wetness index for describing climate situation is proposed in this paper. It is the sum over twelve of the monthly moisture index which is the standardized monthly precipitation. It is more meaningful and representative than the index of yearly precipitation. The series of the yearly dryness/wetness index in Beijing for the period from 1869 to 1987 have been built. Furthermore, it is investigated using power spectral analysis and! variance analysis for its characteristics of the periodic variation, and is found that the mainr periods are 5-yr and 22-yr.
The period patterns, for 5-yr and 22-yr are extracted, by means of the period pattern method proposed in this paper. The patterns are represented by the eigenvectors of the cross-product matrix of the period matrix whose elements are from the original series arranged as, an array according to the length of the period.
The forecasting of the dryness/wetness index is completed through the regression equation in which the period patterns are considered as the predictors. The results show that the water supplement will probably get improvement in Beijing by the end of this century.
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
1990年第1期102-109,共8页
Acta Geographica Sinica
关键词
北京
旱涝
指数
变化规律
测试
Drought and flood
The dryness/wetness index
The period pattern me- thod
