【摘要】 通过对甘肃省 5 2 5年旱涝等级资料累积等级及跃变分析表明 ,甘肃日趋干旱化。其中 ,中部和河西地区最严重 ,陇东次之 ,渭水流域最小。河西、中部、陇东和渭水流域气候变化具有明显的差异性 ,近 5 2 5年来中部地区气候跃变不明显。近 2 0 0年来河西地区气候跃变系数具有与陇东、渭水流域相反的变化趋势。近百年来旱涝等级资料的第一主成分有显著的 3年、8年、1 1年周期 ,第二主成分有 1 4年、2 9年的周期。通过对主成分与近 5 0年产量波动关系的研究 ,第一和第二主成分在 7～ 9年和 2～ 2 .44年、2 2年以上周期时影响夏粮产量 ,但二者对夏粮产量均为负贡献 ,它们与产量波动关系极其密切。除超短波外 ,旱涝对产量的影响滞后约半年时间。并通过对干旱累积效应的分析 ,确定了近 5 2 5年发生特大旱的次数、持续时间、等级及其对夏粮的影响。更多还原

【Abstract】 The accumulative total effect and climatic upspring analysis of 525\|year drought and excessive rain ranking data in Gansu shows that drought is increasing. It is severest in the western and central Gansu but Weishui area is the least inflnenced. It also shows that the climatic changes are obviously different in different parts of Gansu. The climatic upspring of the central remains dim during recent 525 years. The climatic upspring coefficient of western Gansu has the change trend opposite to those of eastern Gansu and Weishui area during recent 200 years. The first main component of recent 100 year Through drought and excessive rain ranking data has an obvious 3\|,8\|,11\|year Cyc,the second component 14\|,29\|year Cyc. Through our study their relation with 50\|year yield undulation is that the first and second main component are of minus contribution at 7\|9,2\|2.44, over 22 year Cyc and they have very close relations\|with yield undulation. The effect of drought and excessive rain is delayed about half a year except short waves. Also the analysis of accumulative total drought effect shows the relation of 525 year top grade droughts with tmies,duration,degress and influences on summer yields.更多还原