ch_flow_raster_trend {CSHShydRology}

Raster plot and simple trends of observed streamflows by periods

Description

Creates a raster plot plus trend plots for day of year, which are binned by a number of days (step), and the max, min, and median annual discharge across years. The plot contains four panels based upon binned data.

Usage

ch_flow_raster_trend(
  DF,
  step = 5,
  missing = FALSE,
  metadata = NULL,
  colours = c("lightblue", "cyan", "blue", "slateblue", "darkblue", "red")
)

Arguments

DF

- dataframe of daily flow data as read by ch_read_ECDE_flows

step

- a number indicating the degree of smoothing eg. 1, 5, 11.

missing

If FALSE years with missing data are excluded. If TRUE partial years are included.

metadata

a dataframe of station metadata, default is HYDAT_list.

colours

A vector of colours used for the raster plot. The default is c("lightblue","cyan", "blue", "slateblue", "darkblue", "red").

Details

The four plots are: (1) The maximum,minimum,and median flow with a trend test for each period: red arrows indicate decreases, blue arrows indicate increases. (2) The scale bar for the colours used in the raster plot, (3) The raster plot with a colour for each period and each year where data exist, and (4) A time series plot of the minimum, median, and maximum annual bin values. If there is no trend (p > 0.05) the points are black. Decreasing trends are in red, increasing trends are in blue.

Value

Returns a list containing:

stationID

Station ID eg. 05BB001

missing

How missing values were used FALSE = used, TRUE = removed

step

number of days in a bin

periods

number of periods in a year

period

period numbers i.e. 1:365/step

bins

values for each period in each year

med_period

median for each period

max_period

maximum for each period

min_period

minimum for each period

tau_period

Kendalls Tau for each period

prob_period

probability of Tau for each period

year

years spanning the data

median_year

median bin for each year

max_year

maximum bin for each year

min_year

minimum bin for each year

tau_median_year

value of tau and probability for annual median

tau_maximum_year

value of tau and probability for annual maximum

tau_minimum_year

value of tau and probability for annual minimum

Author(s)

Paul Whitfield

References

Whitfield, P. H., Kraaijenbrink, P. D. A., Shook, K. R., and Pomeroy, J. W. 2021. The Spatial Extent of Hydrological and Landscape Changes across the Mountains and Prairies of Canada in the Mackenzie and Nelson River Basins Based on data from a Warm Season Time Window, Hydrology and Earth Systems Sciences 25: 2513-2541.

See Also

ch_flow_raster

Examples

 data(CAN05AA008)
 mplot <- ch_flow_raster_trend(CAN05AA008, step=5)