seglenplot {lfstat}

Bar chart of recession length

Description

Plots a bar chart to find a good value for argument 'seglength' when using recession.

Usage

seglenplot(lfobj,
           threslevel = 70,
           thresbreaks = c("fixed","monthly","seasonal"),
           thresbreakdays = NULL,
           rainpeaklevel = 0.95,
           na.rm = TRUE)

Arguments

lfobj

An object of class 'lfobj'

threslevel

The threshold level (70 means Q70)

thresbreaks

'fixed' uses a fixed threshold level, 'monthly' calculates the threshold for every month separately, 'seasonal' calculates thresholds for every season defined using 'thresbreakdays'.

thresbreakdays

Needed if thresbreaks = 'seasonal' to define the periods for which separate thresholds should be calculated, see details

rainpeaklevel

A level between 0 and 1 or a logical vector, see details.

na.rm

Should NAs in the series be ignored?

Details

For recession analysis it is necessary to define flood discharge peaks (rain peaks) in the hydrograph. Argument rainpeaklevel defines a day to be a discharge peak, if rainpeaklevel * flow > flow[day before] and rainpeaklevel * flow > flow[day after].

If 'thresbreakdays' or 'seasonbreakdays' is a single day, e.g. '01/06', the start of the hydrological year is taken as the second break day. If more than two seasons are to be specified, a vector of all break days is needed.

Value

A bar chart

Warning

Other then in the manual, we implemented a bar chart instead of a histogram. To save space, empty bars are not plotted!

Author(s)

Daniel Koffler and Gregor Laaha

References

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

See Also

recession

Examples

data(ngaruroro)
seglenplot(ngaruroro)