未来5a华北地区小麦生育期降水量变化趋势分析

Analysis on the Change Trend of Precipitation during Wheat Growth Period in North China in the Next 5 Years

根据北京、天津、太原、石家庄近60 a冬小麦生育期降水量数据,综合运用多年趋势线、3 a滑动平均值法、Hurst指数法、M-K突变分析法,对该地区冬小麦生育期降水量进行分析,同时使用加权马尔可夫链对降水量进行预测,目的是了解华北地区冬小麦生育期自然降水的变化趋势,并对未来降水进行预测。结果表明,近60 a来,冬小麦生育期降水量略呈下降趋势,且各站点差异较大,下降幅度从高到低排序为天津>北京>太原>石家庄。Hurst指数均大于0.5且都接近0.5,表明各站点未来降水变化均具有持续性,但持续性不强。通过M-K突变分析可知,降水突变年份可能出现在20世纪七八十年代,但近年来各地区生育期降水量基本上均呈下降趋势。构建了马尔可夫链降水预测模型,预测精度都在20%以内,完全符合预测标准。比较预测的未来5 a的降水量与之前年份的降水量发现,未来华北地区冬小麦生产区生育期降水量均呈下降趋势,但下降持续性不强。

To understand the trend of natural precipitation during the growth period of winter wheat in North China and predict future precipitation,according to the precipitation data of winter wheat growth period in Beijing,Tianjin,Taiyuan and Shijiazhuang in the past 60 years,the multi-year trend line,3-year sliding average method,Hurst index method and M-K mutation analysis method were comprehensively applied,precipitation was predicted using a weighted Markov chain.The results showed that in the past 60 years,the precipitation of winter wheat growth period had a slight downward trend,and the difference between the stations was large,the order of decline range from high to low was Tianjin>Beijing>Taiyuan>Shijiazhuang.The Hurst index was greater than 0.5 and both were close to 0.5,indicating that the future precipitation changes of each site were persistent,but the persistence was not strong.According to the M-K mutation analysis,the precipitation year might appear in the 1970 s and 1980 s,but in recent years,the precipitation during the growth period had basically declined.On the other hand,the Markov chain precipitation prediction model was constructed,and the prediction accuracy was within 20%,which fully met the prediction criteria.Comparing the predicted precipitation in the next 5 years with the previous annual precipitation,it was found that the precipitation in the winter wheat production area in North China had a downward trend,but the decline was not strong.