add_delta_to_PPT: Additive Precipitation adjustment by a delta value
In Burke-Lauenroth-Lab/rSFSW2: Simulation Framework for SOILWAT2

Additive Precipitation adjustment by a delta value

add_delta_to_PPT(
  data,
  ind_events = NULL,
  addDelta = NULL,
  deltaPerEvent = NULL
)

`data`	A numeric vector. Daily values of precipitation.
`ind_events`	A logical or integer vector of the same length as `data` or `NULL`. If logical, then `TRUE`/`FALSE` for each element/day of `data` whether it precipitates or not. If integer, then the indices of `data` on which it precipitates. If `NULL`, then it will be calculated as `data > 0`.
`addDelta`	A numeric value or `NULL`. The total amount of precipitation that is to be added/removed from `data[ind_events]` together (divided among events), i.e., it requires the same unit as `data`.
`deltaPerEvent`	A numeric vector of the length equal to `sum(ind_events)` or `NULL`. The daily amount of precipitation that is to be added/removed from each `data[ind_events]`, i.e., it requires the same unit as `data`.

Provide one of the arguments addDelta or deltaPerEvent, but not both. The value of addDelta will be evenly split up among ind_events.

A list with two elements

data: A copy of data with adjusted values.
PPT_to_remove: The total amount of precipitation that could not be removed from data due to lack of precipitation.