吉林省九台市作物生育期降水量特征分析

利用吉林省九台市气象站1977—2009年水稻和玉米生育期降水量观测资料,采用线性趋势法、累计距平法、频率分析法、方差分析法对九台市作物生育期降水量特征进行了分析,研究其降雨的随机性、趋势性和周期性,揭示了降水量丰枯交替变化特点以及未来的发展趋势。研究表明,作物生育期降水量呈减小的趋势且存在着丰枯周期变化,降水量主要存在2a、11a周期。

Falling water flow measurement in U shaped channel

This article is mainly based on Dey（2003） test at the level of the U-shaped channel,using the model of sharp crested weir with zero crest, curve fitting, dimensionless flow analysis method derived the equation of discharge with the water-height on vertical drop.This way of water measurement not only used in water without impurity,but also used as a measurement facilities of water with a certain amount of sediment concentration. Derived formula in this article is simple, easy and practical ;the relative error is within the accuracy of 5.26%.