find_date_permanent_snow: Find start date of permanent snow in a winter

In bniebuhr/winteranalyzer: WInTer conditions and CHaracterization for reindeer husbandry

Description

This function uses a time series of snow depth to find the beginning of the permanent snow in a given winter. This is based on calculating the minimum amount of snow in a window of a given temporal length to check if, after a given snow event, there was melting and the snow vanished.

Usage

find_date_permanent_snow(
  date,
  snow_depth,
  plot = TRUE,
  temp.window.size = 14,
  endrule = c("min", "NA", "trim", "keep", "constant", "func")[1],
  align = c("left", "center", "right")[1],
  set_start = NULL,
  debug = FALSE,
  ...
)

Arguments

date	vector. Date of the weather records.
snow_depth	vector. Snow depth values.
plot	logical. Whether the plot of the start date of permanent snow should be plotted or not. Default is 'TRUE'.
temp.window.size	numeric. Size of the temporal window to calculate the minimum amount of snow, in days. Default is 14 days.
endrule	character. String indicating how the values at the beginning and the end, of the array, should be treated. Default is "min". For more options, see the function runmin).
align	character. How should the temporal window be aligned? Default is "left". For more information, see runmin).
set_start	POSIX object. Date and time of the start of the winter. Used mainly for debugging, to test other dates. Default is NULL.
debug	logical. If debugging, plot also the snow depth values after minimum filtering. Default is FALSE.
...

Value

Date object. Start date of the permanent snow in a winter.

Examples

library(dplyr)
data(weather_mittadalen)

weather_2019 <- weather_mittadalen %>%
  dplyr::filter(year == 2019)

with(weather_2019, find_date_permanent_snow(date, snow_depth, temp.window.size = 14))

# not run
with(weather_2019, find_date_permanent_snow(date, snow_depth, temp.window.size = 14,
                                            set_start = lubridate::ymd_h("2018-11-01 00")))

bniebuhr/winteranalyzer documentation built on Dec. 31, 2020, 8:56 p.m.