The function calculates degree days using the following approximations: single or double sine wave, single or double triangulation (University of California Integrated Pest Management Program 2016) . Double approximation methods assume symmetry, such that a day's thermal minimum is equal to that of the previous day. Double sine wave approximation of degree days from Allen (1976) .

degree_days(T_min, T_max, LDT = NA, UDT = NA, method = "single.sine")

Arguments

T_min

numeric Minimum temperature of the day (C).

T_max

numeric Maximum temperature of the day (C).

LDT

numeric lower developmental threshold (C).

UDT

numeric upper developmental threshold (C).

method

character type of method being used. Current choices: "single.sine", "double.sine", "single.triangulation", and "double.triangulation".

Value

numeric degree days (C).

References

Allen JC (1976). “A Modified Sine Wave Method for Calculating Degree Days.” Environmental Entomology, 5(3), 388-396. doi:10.1093/ee/5.3.388 .

University of California Integrated Pest Management Program (2016). Degree Days: Methods. http://ipm.ucanr.edu/WEATHER/ddfigindex.html.

Examples

  degree_days(T_min  = 7, 
              T_max  = 14, 
              LDT    = 12, 
              UDT    = 33, 
              method = "single.sine")
#> [1] 0.47
  degree_days(T_min  = 7, 
              T_max  = 14, 
              LDT    = 12, 
              UDT    = 33, 
              method = "single.triangulation")
#> [1] 0.29