lfstat (version 0.9.4)

MAM: Mean Annual Minimum

Description

Computes the Mean Annual Minimum (MAM-n) for any given n.

Usage

MAM(lfobj, n = 7, year = "any",breakdays = NULL, yearly = FALSE)

Arguments

lfobj

An object of class "lfobj"

n

Mean Annual minimum for n-days, e.g. n=7 computes MAM7

year

The year for which the BFI should be computed. If hyearstart != 1 the BFI is calculated for the hydrological year! "any" means the whole series should be taken. If a vector of years is given, all this years are included in the calculation.

breakdays

A vector of breakdays if the BFI should be calculated for different seasons.

yearly

If TRUE, the BFI is calculated for each hydrological year separately.

Value

specified year. If yearly is true, a vector of the annual BFIs is returned. If breakdays are specified, separated values for every season are given.

Warning

At the moment there is no check for seasonal overlap. E.g. The MAM7 of 1991 and 1992 could take the same days for calculation if the are in n/2-days range. This problem could be avoided by choosing a "meaningfull" hyearstart and breakdays, usually dates out of the low flow seasons.

Details

If breakdays is a single day, e.g. "01/06", the start of the hydrological year is taken as the second breakday. If more than two seasons are to be specified, a vector of all breakdays is needed.

References

Gustard, A. & Demuth, S. (2009) (Eds) Manual on Low-flow Estimation and Prediction. Operational Hydrology Report No. 50, WMO-No. 1029, 136p.

See Also

meanflow,Q95

Examples

data(ngaruroro)
MAM(ngaruroro)
MAM(ngaruroro, n=1) #Mean annual minimum
MAM(ngaruroro, year = c(1991,1995)) #Taking values from 1991 and 1995
MAM(ngaruroro, year = 1991:1995) #Taking values from 1991 to 1995 (1991,1992,...,1995)
MAM(ngaruroro, breakdays = c("01/11","01/05"))
MAM(ngaruroro, year = 1991)