firstFrost: Mean first frost day

In agroclim: Climatic Indices for Agriculture

Mean first frost day

Description

Calculates the first frost day within a predefined period.

Usage

firstFrost(
  mn,
  dates,
  iniday = "07-01",
  endday = "06-30",
  type = "doy",
  thres = 0
)

Arguments

mn	vector of daily minimum temperature series.
dates	vector of dates corresponding with daily temprature series
iniday	first day of the year ("dd-mm") when frost occurrence will be considered.
endday	last day of the year ("dd-mm") when frost occurrence will be considered.
type	type of output. It can be "doy" for day of the year (julian day) or "date" for data format ("dd-mm").
thres	temperature threshold considered to trigger frost occurrence (0 by default).

Details

The function is able to span over years. If the argument "enddate" is a date earlier than "inidate", the considered period will cover from "inidate" to the end of the year and from the beginning of the next year to "enddate".

Value

Depending on argument type, the output will be a numeric vector of julian days (type = "doy") or a vector of characters with dates (type = "date").

Examples

firstFrost(mn = daily_tmin,
            dates = seq.Date(as.Date('1981-01-01'),
                             as.Date('2010-12-31'), by ='day'),
            iniday = '07-01',
            endday = '06-30',
            type = 'doy')

agroclim documentation built on Oct. 14, 2022, 9:05 a.m.