中国雨日变化趋势的分形研究

Fractal research on rainy day change trend in China

利用1951-2002年中国752个台站的雨日资料,运用分形理论和R/S分析法,研究并预测了中国五大降水区年雨日的气候变化趋势。研究表明:中国五大降水区未来的年雨日变化趋势与过去50 a的变化有着很好的自相似性。为了更深入研究雨日的未来的变化,设计了两项Hurst指数试验,用两项试验结果与年雨日年际变化趋势的对应关系来推断未来的变化趋势及其转折与突变。结果表明:中国五大降水区年雨日有着一致的减少趋势,但其变化呈现显著的地域分异特征。依照五大降水区的气候倾向率,西北区、西南区、青藏高原区、东部北方区、东部南方区未来平均每10 a雨日减少分别为4.1d,11.4d,3.7d,6.8d和5.9d,其中西南区年雨日减少最多。期间,中国五大降水区虽有气候变化的转折,但不存在雨日气候变化的突变点。

Using the rainy day data from the year 1951 to 2002 years in 752 meteorological stations of China, the authors studied and forecasted climatic change of annual rainy days in five major precipitation regions of China with basic principle of the fractal theory and R/S analytic method. The study indicates that, there is a similarity on climatic change of annual rainy day in future to that in past 50 years. Two items of Hurst index experiment were designed to further research on climatic change of rainy day, which are used to forecast the tendency, transition and sudden change of rainy day according to the corresponding relation between two experimental results and the years change tendency of rainy day. The result indicates that, annual rainy days has completely consistent tendency to reduce in the five regions of China, but the change of rainy day shows different characteristic in regions. The rainy day will reduce 6.8 days every 10 years in the next 10 years in the North of Eastern China and 5.9 days every 10 years in the South of Eastern China. The reduction of rainy days in southwestern China is the most, which will be 11.7 days every 10 years . And the reduction of that in Tibet Plateau and northwestern China is the lowest, which will be 3.7 and 4. 1 days every 10 years respectively and be not stable. And there is a transition of climatic change, but there is not sudden change of climatic change of rainy day in this period.