Get proportion of rainfall above reference

Calculates the proportion of rainfall above the refrerence_rainfall value. Usually the reference corresponds to the 95th percentile of a climate normal/reference period. The proportion is often calculated in an annual basis and is a measure of the proportion of annual total rain that falls in intense events. This measure provides information about the importance of intense rainfall events for total annual rainfall.

precipitation_above_reference(
  precipitation,
  reference_precipitation,
  wet_day_threshold = 1
)

Arguments

precipitation

vector with rainfall values

reference_precipitation

reference value of precipitation

wet_day_threshold

Numeric. Amount of precipitation at which the day is considered a wet day. Defaults to 1.

Value

a value between 0 and 1

See also

Other rainfall functions: get_reference_precipitation()

Examples

library(dplyr)
# Simulate one measurement of rain per day for 10 years
rainfall <- rlnorm(10*365)
years <- rep(2001:2010, each = 365)
rain_data <- tibble(rainfall = rainfall, year = years)
# We chose a climate normal
climate_normal <- c(2001, 2005)

rain_data %>%
# calculate reference rainfall
  mutate(ref = get_reference_precipitation(rainfall,
                                            year,
                                            climate_normal,
                                            percentile = 95L)) %>%
# calculate prorportion of rainfall above reference
  group_by(year) %>%
  summarise(prop_above = precipitation_above_reference(rainfall, ref))
#> # A tibble: 10 × 2
#>     year prop_above
#>    <int>      <dbl>
#>  1  2001     0.253 
#>  2  2002     0.196 
#>  3  2003     0.187 
#>  4  2004     0.156 
#>  5  2005     0.157 
#>  6  2006     0.171 
#>  7  2007     0.333 
#>  8  2008     0.183 
#>  9  2009     0.246 
#> 10  2010     0.0986