近50年来黄河流域400 mm等雨量线空间变化研究

以黄河流域及周边地区1 026个雨量（水文）站1956—2000年逐日降水过程资料为基础，以GIS技术为关键数据处理平台，建立等值线加权平均位置的定量化表征方法，采用时间序列分析技术，对黄河流域近50年来400 mm等雨量线的空间位移特征进行了系统揭示。1956—2000年间，黄河流域多年平均降雨量为454.62 mm；400 mm等雨量线加权平均位置坐标为（105°0′4″E，36°57′54″N）。整体上看，近50年来，黄河流域400 mm等雨量在纬向上的移动是典型的平稳随机序列过程；在经向上的移动尚不能满足平稳随机序列过程。趋势检验结果表明，黄河流域400 mm等雨量线有向东和向南发生移动的趋势，且向东移动的趋势显著。功率谱分析表明，黄河流域400 mm等雨量线在经向上发生迁移的显著周期为3年；在经向和纬向上均有7年和2年周期；同时，位移具有反向持久性。

A STUDY OF THE SPATIAL SHIFT OF 400 mm-RAINFALL CONTOURS IN THE YELLOW RIVER BASIN DURING RECENT 50 YEARS

Based on the daily serial rainfall data of 1026 rainfall gauges (or hydrological gauges) in the Yellow river basin and its surrounding regions during the period from 1956 to 2000, and on the key data disposal platform of GIS techniques, the spatial shift of 400mm rainfall contours in the Yellow river basin in the past 50 years has been analyzed with the method of time serials analysis and the quantified weighted average location (QWAL) token method of contours has been founded in this paper. The multi year yearly average rainfall in the Yellow river basin was 454.62mm and the QWAL of 400mm rainfall contours was (105o0′4″E，36o57′54″N) from 1956 to 2000. In the whole, the latitudinal shift of 400 mm rainfall contours in the Yellow River Basin in the recent 50 years has been a typical stationary random sequence, however the longitudinal shift serials cannot meet the requirement of the stationary random sequence. Trend test shows that spatial shift of the 400 mm rainfall contours in the Yellow river basin has the eastern and southern trends, while the eastern trend is notable. Power spectrum analysis indicates that the longitudinal shift of the 400 mm rainfall contours in the Yellow river basin has the notable cycle of 3 years, both longitudinal and latitudinal shifts have the 7 year and 2 year cycle. Hurst index shows that the displacement of QWALs of 400mm rainfall contours has the reverse permanence features. 