JDay_earlier function

Check whether a Julian date is before or after another one

For two Julian dates, this function checks whether the first date is earlier than the second date within a user-defined phenological season. This is particularly useful for seasons that start in one year and end in the next, because simple > or < operations can produce wrong results then.

JDay_earlier(check_date, ref_date, season = c(1, 366))

Arguments

• check_date: integer ranging from 1 to 366, indicating a Julian date. This is the date for which to check whether it is before the reference date. If this is a vector, all elements are checked against the reference date.
• ref_date: integer ranging from 1 to 366, indicating a Julian date. This is the reference date.
• season: integer vector of length 2, specifying the beginning and end of the phenology season, respectivcely.

Returns

Boolean result (TRUE/FALSE) of the comparison.

Examples

JDay_earlier(check_date=10,ref_date=365,season=c(305,59))

Author(s)

Eike Luedeling