IDHeatwavesAlternative: Identify heat waves in a time series

In futureheatwaves: Find, Characterize, and Explore Extreme Events in Climate Projections

Description

This function identifies heat waves in a time series of temperature data using a heat wave definition that a heat wave must be a certain number of days above the greater of either a given threshold or 80 degrees Fahrenheit.

Usage

IDHeatwavesAlternative(threshold, datafr, numDays)

Arguments

threshold	Numeric string with threshold temperature used in the heat wave definition, in degrees Fahrenheit.
datafr	A dataframe with daily temperature projections in the the city being processed. This dataframe must have two columns: (1) the first column must have the date of each observation, with class "Date" and; (2) the second column must have temperatures in degrees Fahrenheit. In the normal running of this package, this dataframe will be generated by the closure created by createCityProcessor.
numDays	Integer greater than 0 giving the number of days to use in the extreme event definition (e.g., numDays = 2 would define a heat wave as two or more days above the threshold temperature).

Value

Returns the dataframe entered as datafr, but with new columns providing heat wave identifiers. The returned dataframe will have new columns for whether a day was part of a heat wave (hw, 0 / 1), and if it was part of a heat wave, the number of the heat wave (hw.number).

Note

There are a few cases near the edges of data frames when this function would return that a day was not a heat wave when it was. First, if the first day of the dataset is a heat wave because preceeding days exceeded the threshold, but the second day in the dataframe is not above the threshold, this function would not capture that the first day was a heat wave. A similar caveat applies to the last day in the dataframe. In northern hemisphere studies, this should not be a concern, as it is unlikely that Jan. 1 or Dec. 31 would qualify as a heat wave. However, care should be taken when using this function either with Southern Hemisphere cities or when exploring exposures that, unlike heat waves, may occur very early or late in the calendar year.

Examples

data(datafr)
hw_ids <- IDHeatwavesAlternative(threshold = 80, datafr = datafr,
                                 numDays = 3)

futureheatwaves documentation built on May 2, 2019, 9:43 a.m.