metrics.all: Streamflow metrics

In FlowScreen: Daily Streamflow Trend and Change Point Screening

Description

Calculates 30 different flow metrics, 10 each for high flows, low flows, and baseflow.

Usage

metrics.all(TS, Qmax = 0.95, Dur = 5, Qdr = 0.2, WinSize = 30,
  Season = c(4:9), NAthresh = 0.5, language = "English")

Arguments

TS	output from create.ts containing a data.frame of flow time series
Qmax	Numeric value for peaks over threshold quantile. Default is 0.95.
Dur	Numeric value for minimum number of days between flood peaks. Default is 5.
Qdr	Numeric value for drought quantile. Default is 0.2, i.e. the 80th percentile of the flow duration curve.
WinSize	Numeric value for moving window size (in days) for the moving window quantile drought threshold. See mqt. Default is 30.
Season	Numeric vector of months during which droughts start. Default is c(4:9) for non-frost season droughts.
NAthresh	Numeric value indicating the threshold for missing data points in any one year. Default is 0.5, indicating that years with more than 50 percent missing data will be omitted from the metric calculations. This value should always be set to greater than 0.1, as years with fewer observations than approximately 1 month will cause errors.
language	Character string indicating the language to be used for naming the different plot metrics. These names are used in screen.summary to label individual plots. Options are "English" or "French". Default is "English".

Details

This function calculates streamflow metrics and calculates the prewhitened trend using zyp.trend.vector and looks for changpoints in mean and variance using cpt.meanvar This function is intended for use as a data quality screening tool aimed at identifying streamflow records with anthropogenic impacts and should not be used to complete a temporal trend analysis, as the calculated metrics may not be appropriate for all catchments. See the functions linked in the following section for details on how each metric is calculated.

Value

Returns a list with the following elements:

metricTS: a list containing a vector of each metric calculated. Each vector has a times attribute providing either the year for metrics with one observation per year or a date for metrics that may have more than one observation per year (e.g., Peaks Over Threshold). This list has the following elements:

• Annual Maximum Series - calculated with pk.max

• Day of Annual Maximum - calculated with pk.max.doy

• Peaks Over Threshold (Qmax) - calculated with pks

• Inter-Event Duration - calculated with pks.dur

• Q80 - calculated with Qn

• Q90 - calculated with Qn

• Day of Year 25 percent Annual Volume - calculated with pk.cov

• Center of Volume - calculated with pk.cov

• Day of Year 75 percent Annual Volume - calculated with pk.cov

• Duration between 25 percent and 75 percent Annual Volume - calculated with cov

• Q10 - calculated with Qn

• Q25 - calculated with Qn

• Drought Start - calculated with dr.seas

• Drought Center - calculated with dr.seas

• Drought End - calculated with dr.seas

• Drought Duration - calculated with dr.seas

• Drought Severity - calculated with dr.seas

• Annual Minimum Flow - calculated with MAMn

• Mean Annual Minimum 7-day Flow - calculated with MAMn

• Mean Annual Minimum 10-day Flow - calculated with MAMn

• Mean Daily Discharge - calculated with bf.stats

• Annual Baseflow Volume - calculated with bf.stats

• Annual Mean Baseflow - calculated with bf.stats

• Annual Maximum Baseflow - calculated with bf.stats

• Annual Minimum Baseflow - calculated with bf.stats

• Mean Annual Baseflow Index - calculated with bf.stats

• Day of Year 25 percent Baseflow Volume - calculated with pk.bf.stats

• Center of Volume Baseflow - calculated with pk.bf.stats

• Day of Year 75 percent Baseflow Volume - calculated with pk.bf.stats

• Duration between 25 percent and 75 percent Baseflow Volume - calculated with pk.bf.stats

tcpRes: this list contains the results of the trend and changepoint analysis for each of the metrics in the metricTS list described above. Each list element is a list containing the following elements:

• MetricID - integer used to identify the metric

• MetricName - Name of the metric.

• Slope - numeric vector containing the intercept and slope of the prewhitened linear trend calculated using the Yue Pilon method. See zyp.trend.vector

• ci1 - upper bound of the trend's 95 percent confidence interval

• ci2 - lower bound of the trend's 95 percent conficence interval

• pval - Kendall's P-value computed for the detrended time series

• cpts - Most probable location of a changepoint, if one is detected.

• means - Mean before and after the changepoint

• NumObs - The number of data points for the metric

inData: A data.frame of the original input daily streamflow time series.

OmitYrs: A data.frame containing the years and the number of observations for any years omitted from the analysis due to insufficient data. If no years were omitted, NA is returned.

Author(s)

Jennifer Dierauer

See Also

See the documentation for individual functions linked in the output description for a details on methods.

See screen.metric to create individual plots for each metric.

Examples

# load subset of daily streamflow time series for the Caniapiscau River
data(cania.sub.ts)

## Not run: 
# calculate low flow, high flow, and baseflow metrics
res <- metrics.all(cania.sub.ts)

## End(Not run)

Example output

If singularity problems occur divide data by a factor, perhaps 1000 

FlowScreen documentation built on May 2, 2019, 1:09 p.m.