R/calc_longterm_monthly_stats.R
calc_longterm_monthly_stats.Rd
Calculates the longterm mean, median, maximum, minimum, and percentiles of annual monthly mean flow values for all months and all data (Longterm) from a daily streamflow data set. Calculates statistics from all values, unless specified. Returns a tibble with statistics.
calc_longterm_monthly_stats( data, dates = Date, values = Value, groups = STATION_NUMBER, station_number, percentiles = c(10, 90), roll_days = 1, roll_align = "right", water_year_start = 1, start_year, end_year, exclude_years, months = 1:12, complete_years = FALSE, include_annual = TRUE, custom_months, custom_months_label, transpose = FALSE, ignore_missing = FALSE )
data  Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers).
Leave blank if using 

dates  Name of column in 
values  Name of column in 
groups  Name of column in 
station_number  Character string vector of seven digit Water Survey of Canada station numbers (e.g. 
percentiles  Numeric vector of percentiles to calculate. Set to 
roll_days  Numeric value of the number of days to apply a rolling mean. Default 
roll_align  Character string identifying the direction of the rolling mean from the specified date, either by the first
( 
water_year_start  Numeric value indicating the month ( 
start_year  Numeric value of the first year to consider for analysis. Leave blank to use the first year of the source data. 
end_year  Numeric value of the last year to consider for analysis. Leave blank to use the last year of the source data. 
exclude_years  Numeric vector of years to exclude from analysis. Leave blank to include all years. 
months  Numeric vector of months to include in analysis (e.g. 
complete_years  Logical values indicating whether to include only years with complete data in analysis. Default 
include_annual  Logical value indicating whether to include annual calculation of all months. Default 
custom_months  Numeric vector of months to combine to summarize (ex. 
custom_months_label  Character string to label custom months. For example, if 
transpose  Logical value indicating whether to transpose rows and columns of results. Default 
ignore_missing  Logical value indicating whether dates with missing values should be included in the calculation. If

A tibble data frame with the following columns:
month of the year, included 'Annual' for all months, and 'CustomMonths' if selected
mean of all annual monthly means for a given month over all years
median of all annual monthly means for a given month over all years
maximum of all annual monthly means for a given month over all years
minimum of all annual monthly means for a given month over all years
each nth percentile selected for annual monthly means for a given month over all years
annual 10th percentile selected for annual monthly means for a given month over all years
annual 90th percentile selected for annual monthly means for a given month over all years
# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat()) if (file.exists(tidyhydat::hy_downloaded_db())) { # Calculate longterm monthly statistics using data argument with defaults flow_data < tidyhydat::hy_daily_flows(station_number = "08NM116") calc_longterm_monthly_stats(data = flow_data, start_year = 1980) # Calculate longterm monthly statistics using station_number argument with defaults calc_longterm_monthly_stats(station_number = "08NM116", start_year = 1980) # Calculate longterm monthly statistics regardless if there is missing data for a given year calc_longterm_monthly_stats(station_number = "08NM116", ignore_missing = TRUE) # Calculate longterm monthly statistics for water years starting in October calc_longterm_monthly_stats(station_number = "08NM116", start_year = 1980, water_year_start = 10) # Calculate longterm monthly statistics with custom years calc_longterm_monthly_stats(station_number = "08NM116", start_year = 1981, end_year = 2010, exclude_years = c(1991,1993:1995)) # Calculate longterm monthly statistics for 7day flows for JulySeptember months only, # with 25 and 75th percentiles calc_longterm_monthly_stats(station_number = "08NM116", roll_days = 7, months = 7:9, percentiles = c(25,75), ignore_missing = TRUE, include_annual = FALSE) # removes the Longterm numbers # Calculate longterm monthly statistics and add custom stats for JulySeptember calc_longterm_monthly_stats(station_number = "08NM116", start_year = 1980, custom_months = 7:9, custom_months_label = "Summer") }#> Warning: One or more calculations included missing values and NA's were produced. Filter data for complete years or months, or use to ignore_missing = TRUE to ignore missing values.#> # A tibble: 14 x 8 #> STATION_NUMBER Month Mean Median Maximum Minimum P10 P90 #> <chr> <fct> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> #> 1 08NM116 Jan 1.16 0.972 6.12 0.316 0.619 1.63 #> 2 08NM116 Feb 1.19 0.981 3.83 0.353 0.612 1.81 #> 3 08NM116 Mar 1.89 1.49 6.93 0.507 0.906 3.10 #> 4 08NM116 Apr 8.65 8.26 23.9 1.60 3.49 13.3 #> 5 08NM116 May 24.6 23.9 45.0 14.0 15.7 32.9 #> 6 08NM116 Jun 22.0 21.5 48.6 3.15 11.4 34.1 #> 7 08NM116 Jul 6.28 4.20 25.6 0.921 1.90 13.5 #> 8 08NM116 Aug 2.03 1.71 5.07 0.872 1.13 3.36 #> 9 08NM116 Sep 2.10 1.72 6.06 0.700 0.986 3.74 #> 10 08NM116 Oct 2.06 1.84 5.25 0.533 0.989 3.44 #> 11 08NM116 Nov 2.01 1.61 5.41 0.498 0.715 3.53 #> 12 08NM116 Dec 1.29 1.10 3.65 0.450 0.537 2.20 #> 13 08NM116 Annual 6.28 6.26 11.1 2.88 4.18 8.23 #> 14 08NM116 Summer 3.48 2.67 11.5 1.06 1.40 6.30