模型参数及率定：

 

目标

-         总水量平衡

-         径流过程线形状相似

-         洪峰拟合

-         低流量拟合

最初调整:

-         Lmax 和 Umax ：平衡水量

-         CQOF 和 CK12 ：调整流量峰值

-         CKBF ：调整基流

进一步的参数调整（重复进行）:

-         确定某个参数值变化是否改进率定；

-         一次只调整一个参数值；

-         第一次尝试时数值改变幅度要大些

 

需3－5年长序列的水文、气象观测资料用于NAM率定 

 

初始条件

-         须输入各蓄水层的蓄水量（在界面是以相对比例因子输入），估测的径流量和基流。

-         如果模拟是从枯季末开始，则可以设置根区含水量为其最大含水量的0.1-0.3倍，基流设为出口处的实测流量值，其余参数都设为0。

-         可以通过模拟开始几年前的模拟结果作为本次模拟的初始条件。

考虑初始条件估测的可能出现的误差情况，建议忽略模拟期前3-6个月的结果。

率定时，请参考以下：

A calibration usually commences by adjusting the water balance in the

system. The total evapotranspiration over a certain period should correspond

to the accumulated net precipitation minus runoff. The evapotranspiration

will increase when increasing the maximum water contents in

the surface storage Umax and the root zone storage Lmax, and vice versa.

The peak runoff events are caused by large quantities of overland flow.

The peak volume can be adjusted by changing the overland flow runoff

coefficient (CQOF), whereas the shape of the peak depends on the time

constant used in the runoff routing (CK12).

The amount of base flow is affected by the other runoff components; a

decrease in overland flow or interflow will result in a higher baseflow, and

vice versa. The shape of the baseflow recession is a function of the baseflow

time constant (CKBF). If the baseflow recession changes to a slower

recession after a certain time, a lower groundwater reservoir should be

added, including calibration of CQlow and CKlow.

Initially, the root zone threshold values TOF, TIF and TG can be set to

zero. After a first round of calibration of the parameters Umax, Lmax,

CQOF, CK12 and CKBF, the threshold parameters can be adjusted for further

refinement of the simulation results.

For individual calibration of the groundwater parameters GWLBF0 and SY,

the simulated groundwater level is compared to observed groundwater

levels. Inclusion of the shallow groundwater reservoir description is

important in lowland areas, as found e.g. in swamps or river delta areas,

where the groundwater table may reach the ground surface during the wet

season.

NAM模型参考文献：

/41/ Abbott, M.B. and J.C. Refsgaard (eds) (1996), Distributed Hydrological

Modelling, Kluwer Academic Press, The Netherlands, 321

p.

/42/ Brakensiek, D.L. (1979), Comments on 'Empirical Equations for

some soil Hydraulic Properties' by Roger B. Clapp and George M.

Hornberger, Water Resources Research, 15 (4), 989-990.

/43/ Brakensiek, D.L., Engleman, R.L. and Rawls, W.J. (1981), Variation

within texture classes of soil water parameters, Trans. ASAE,

24, 335-339.

/44/ Cosby, B.J., Hornberger, G.M., Clapp, R.B. and Ginn, T.R. (1984),

A statistical exploration of the relationships of soil moisture characteristics

to the physical properties of soils, Water Resources

Research, 20 (6), 682-690.

/45/ Doorenbos, J. and W.O. Pruitt (1977), Guidelines for Predicting

Crop Water Requirements. FAO Irrigation and Drainage paper No.

24. Food and Agricultural Organization of the United Nations.

/46/ Duan, Q., Sorooshian, S., Gupta, V. (1992), Effective and efficient

global optimization for conceptual rainfall-runoff models, Water

Resources Research, 28(4), 1015-1031.

/47/ Li, R.-M., Stevens, M.A. and Simons, D.B. (1976), Solutions to

Green-Ampt infiltration equations, J. Irrig. and Drain. Div., Amer.

Soc. Civil. Eng., 102 (IR2), 239-248.