近半世纪华北干旱化趋势研究

首先 ,提出了一种新的干湿指数 ,该指数的主要特点是它是相对于一地的水份需要量而言的 ,并且针对干旱的特点 ,考虑了前期降水对近期干旱现象的贡献。利用该指数 ,对我国华北近几十年来的干湿变化进行了讨论 ,发现近半个世纪以来 ,华北的干旱化趋势是十分明显的。其次 ,对华北干旱化的季节结构和周期性变化特点进行了研究 ,得出了一些有意义的结论。最后 ,讨论了近年来华北的连续干旱现象 ,指出近两年来的连续干旱是近 5 0年来最为严重的 ,并且到目前为止仍没有明显的结束趋势 ,值得我们进一步关注。

Drought trend in North China in recent half century

A new index for drought and wetness is presented, which characterizes demand of water in some place and reflects the contribution of prephase precipitation to recent drought. This paper discusses the change of drought and wetness in North China in recent several decades. It is discovered that the drought trend in North China in recent half century is most obvious. Seasonal character and periodical change of drought trend in North China are investigated and some useful conclusions are drawn. Finally, the paper discusses successive drought phenomenon in North China in recent years and points out that the successive drought occurred in recent two years is the most serious in recent half century and without ending trace and it should be concerned about.