一、郑州市的干旱灾害和特点郑州市地跨淮河、黄河两大流域,是南北气候的过渡地带,常年平均降雨量628mm。降雨量年际变化大,年内分布不均,汛期降雨量占全年降雨量的70%左右。郑州市又是从豫西山区到豫东平原的过渡地带。气候和地形的两个过渡带决定了郑州市旱涝灾害频繁,特别是干旱灾害极为严重。建国后,中原地区几乎年年发生干旱,其中1961年受旱面积21.9万hm~2,1986年受旱面积23.5万hm~2,1991年受旱面积30.8万hm~2。最近一次较大旱 I. DROUGHT DISCOVERY AND CHARACTERISTICS IN ZHENGZHOU Zhengzhou covers the Huaihe and Yellow River basins. It is a transition zone between the north and the south. The average annual rainfall is 628mm. The interannual variation of rainfall is large with uneven distribution during the year, and rainfall in the flood season accounts for about 70% of the annual rainfall. Zhengzhou City is also the transition zone from the mountainous area in the west of Henan to the plain in the east of Henan Province. The two transitional zones of climate and topography determine the frequent droughts and floods in Zhengzhou City, especially the severe drought. After the founding of the People’s Republic of China, the drought in the Central Plains took place almost annually, of which 219,000 hectares were affected in 1961, 235,000 hectares in 1986, and 308,000 hectares in 1991. The last major drought