摘要
松花江 (哈尔滨江段 )、嫩江 (江桥站 )洪水可划分成 5个等级。第 1级为无洪水 ,又可分为2个副级 ,即 1a级为中水 ,1b级为枯水 ;第 2级为警戒洪水 ;第 3级为一般洪水 ;第 4级为大洪水 ;第 5级为特大洪水。各级划分是采用流体力学能量方程 ,位能与动能之和用E指数表示 ,再将E值按P -Ⅲ型分布将其密度函数转换成Z指数 ,按Z值正态分布特点划分洪水等级。松花江在98年中共发生过 19次洪水 ,嫩江在 47年中共发生过 10次洪水 ,可见松花江洪水次数远高于嫩江洪水次数。 90年代这两江洪水有多发趋势。
Songhua River(Harbin reach)and Nen River(Jiangqiao Station)floods can be classified into five grades . The fifth grade means severe flood;The fourth grade means heavy flood;The third grade means nomal flood;The second grade means warn flood and the first grade means no flood.The first grade contains tow subgrades,1a stands for midium water and 1b stand for low water.The main method employed in classifying grades is Energy Equation in Hydromechanics.E index stands for the sum of potential energy and kinetic energy.According to P-Ⅲ type distribution , its density function is converted into Z index.Finally,the flood grades can be classified according to the property of normal distribution of Z index. This method is objective,quantative,easy to apply and to remeber.Flood occur in Songhua river 19 times in the 98 years.Flood occur in nen river 10 times in the 47years,what is more times that flood occur in Songhua river is more than that in Nen river.and that flood in the rivers in the years of 90th appears tendency of uptrend.
出处
《黑龙江气象》
2000年第1期13-16,共4页
Heilongjiang Meteorology
基金
黑龙江省科学技术委员会下达"松花江洪水经济环境影响评估及预报对策研究"(1 999~ 2 0 0 0年攻关项目 )
