水文頻率適線法案例（目估）

主講：馬雪琴楊凌職業(yè)技術(shù)學(xué)院副教授

工程水文及水利計(jì)算年徑流水文頻率計(jì)算——水文頻率適線法案例【例】某河某斷面的流量資料見(jiàn)下表（單位m3/s)。試用適線法推求該站年徑流量的頻率曲線，并確定相應(yīng)于頻率為P=10%設(shè)計(jì)豐水年、P=50%設(shè)計(jì)枯水年、P=90%設(shè)計(jì)枯水年的設(shè)計(jì)年徑流量。年份1956195719581959196019611962196319641965年徑流量766.9346.4459.0627.9646.5516.5345.1581.3936.5289.6年份1966196719681969197019711972197319741975年徑流量621.5581.8387.7660.3502.9497.1450.1682.3497.5365.1年份197619771978197919801981198219831984

年徑流量582.0822.0500.6670.2466.1429.8406.8374.7413.2年份(m3/s)序號(hào)

①②③④⑤⑥⑦⑧1956766.91936.53.31.7600.7600.57761957346.428226.71.5450.5450.29701958459.03766.910.01.4420.4420.19541959627.94682.313.31.2830.2830.08011960646.55670.216.71.2600.2600.06761961516.56660.320.01.2410.2410.05811962345.17646.523.31.2150.2150.04621963581.38627.926.71.1800.1800.03241964936.59621.530.01.1680.1680.02821965289.61058233.31.0940.0940.00881966621.511581.836.71.0940.0940.00881967581.812581.340.01.0930.0930.00861968387.713516.543.30.971-0.0290.00081969660.314502.946.70.945-0.0550.00301970502.915500.650.00.941-0.0590.00351971497.116497.553.30.935-0.0650.00421972450.117497.156.70.934-0.0660.00441973682.318466.160.00.876-0.1240.01541974497.51945963.30.863-0.1370.01881975365.120450.166.70.846-0.1540.02371976582.021429.870.00.808-0.1920.03691977822.022413.273.30.777-0.2230.04971978500.623406.876.70.765-0.2350.05521979670.224387.780.00.729-0.2710.07341980466.125374.783.30.704-0.2960.08761981429.826365.186.70.686-0.3140.09861982406.827346.490.00.651-0.3490.12181983374.728345.193.30.649-0.3510.12321984413.229289.696.70.544-0.4560.2079合計(jì)15427.4

28.999-0.0012.3369解：①計(jì)算、點(diǎn)繪經(jīng)驗(yàn)點(diǎn)②算繪理論頻率曲線

由統(tǒng)計(jì)參數(shù)初值，均值=532m3/s，變差系數(shù)Cv=0.30，設(shè)偏態(tài)系數(shù)Cs=2Cv=0.60，作為初試值，查模比系數(shù)表，計(jì)算不同頻率P相應(yīng)的xP值并列表，繪制理論頻率曲線，并與經(jīng)驗(yàn)點(diǎn)進(jìn)行擬合。m3/s③適線適線過(guò)程頻率p(%)(1)12510205075909599第一次適線Cv=0.30,Cs=2Cvkp(2)1.831.711.541.401.240.970.780.640.560.44xp(3)973.6909.7819.3744.8659.7516.0415.0340.5297.9234.1Cv=0.30Cs=2Cv曲線中部偏于點(diǎn)上方曲線上下部偏于點(diǎn)下方③適線適線過(guò)程頻率p(%)(1)12510205075909599第二次適線Cv=0.32,Cs=3Cv(采用)kp(4)1.961.811.601.431.240.950.770.640.580.48xp(5)1042.7962.9851.2760.8659.7505.4409.6340.5308.6255.4Cv=0.32Cs=3Cv適線結(jié)果

由曲線可以得出，頻率10%、50%、90%對(duì)應(yīng)