add_seasons: Add a column of seasons

In fasstr: Analyze, Summarize, and Visualize Daily Streamflow Data

Add a column of seasons

Description

Adds a column of seasons identifiers to a data frame with a column of dates called 'Date'. The length of seasons, in months, is provided using the seasons_length argument. As seasons are grouped by months the length of the seasons must be divisible into 12 with one of the following season lengths: 1, 2, 3, 4, 6, or 12 months. The start of the first season coincides with the start month of each year; 'Jan-Jun' for 6-month seasons starting with calendar years or 'Dec-Feb' for 3-month seasons starting with water year starting in December.

Usage

add_seasons(
  data,
  dates = Date,
  station_number,
  water_year_start = 1,
  seasons_length
)

Arguments

data	Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers). Leave blank or set to NULL if using station_number argument.
dates	Name of column in data that contains dates formatted YYYY-MM-DD. Only required if dates column name is not 'Date' (default). Leave blank or set to NULL if using station_number argument.
station_number	Character string vector of seven digit Water Survey of Canada station numbers (e.g. "08NM116") of which to extract daily streamflow data from a HYDAT database. Requires tidyhydat package and a HYDAT database. Leave blank if using data argument.
water_year_start	Numeric value indicating the month (1 through 12) of the start of water year for analysis. Default 1.
seasons_length	Numeric value indicating the desired length of seasons in months, divisible into 12. Required.

Value

A tibble data frame of the source data with additional column:

Season

season identifier labelled by the start and end month of the season

Examples

# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {

# Add a column with four annual seasons starting in January
add_seasons(station_number = "08NM116",
            seasons_length = 4)

# Add a column with two annual seasons (of 6 months length) starting in October
add_seasons(station_number = "08NM116", 
            water_year_start = 10,
            seasons_length = 6)
            
}

fasstr documentation built on March 31, 2023, 10:25 p.m.