FlowScreen (version 2.0)

MAMn: Calculate mean annual minimum n-day flows

Description

This function calculates the calculates the mean annual minimum n-day flow by calendar year or by hydrologic year. This function can also be used to find the annual minimum series by setting n=1.

Usage

MAMn(TS, n = 7, by = "hyear", threshold.missing = 0.5)

Value

Returns a numeric vector containing the calculated MAM n-day flow for each year in the input time series. The "times" attribute provides the corresponding year for each calculated value. Note: a partial start year or end year in the time series that exceeds the threshold set by 'threshold.missing' will be automatically truncated from the output.

Arguments

TS

data.frame of streamflow time series loaded with read.flows.

n

Numeric value for the number of days in the n-day flow period. Default is 7.

by

Character string indicating whether to use hydrologic years or calendar years. Default is "hyear". Other option is "year".

threshold.missing

Numeric value indicating the fraction of data that can be missing in a single year. Years with a missing data above this threshold will have NA values returned. Default is 0.5 (max of 50% missing data allowed).

Author

Jennifer Dierauer

See Also

screen.metric

Examples

data(caniapiscau)
cania.ts <- create.ts(caniapiscau, hyrstart = 4)
cania.ts <- drop.years(cania.ts)
cania.ts <- set.plot.titles(cania.ts, 
title.elements = c("StationID", "StnName", "StateProv"))

# find the annual minimum series and plot 
res <- MAMn(cania.ts, n=1)
res2 <- screen.metric(res, ylabel = "Q (m3/s)", title = TRUE)

# do the same with MAM 7-day flow instead of annual minimum
res <- MAMn(cania.ts, n=7)
res2 <- screen.metric(res, ylabel = "Q (m3/s)", title = TRUE)