ch_flow_raster_trend {CSHShydRology}

R Documentation

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)

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