Convert a summed variable to a rate

Converts accumulated or summed meteorological variables (e.g., precipitation) to a rate by dividing by the time interval between observations. This is useful for standardizing variables recorded as cumulative sums to rate units (per second).

Usage

convert_sum_to_rate(dt, v_var_to_convert = NA, time_name = NA)

Arguments

dt

A `data.table` containing the variables to convert. Modified by reference.

v_var_to_convert

Character vector of column names in `dt` to convert from a sum to a rate. For example, `c("P_12_1_1", "LWS_4_1_2")`. If `NA` (default), no conversion is performed.

time_name

Character string specifying the name of the time column in `dt` (e.g., `"DATECT"`). Used to calculate the interval length between the first two observations. If `NA` (default), an error will occur.

Value

The `data.table` `dt` with specified columns converted to rates (units per second). The input table is modified by reference and invisibly returned.

Details

The function calculates the time interval from the first two observations and divides all specified variables by this interval length (in seconds). Units are converted from their original units to rates per second.

Note: Unit attributes in the metadata are not automatically updated; ensure metadata reflects the new rate units after conversion.

See also

add_era5 for an application converting ERA5 precipitation