gddcal {acdcR}

Calculating growing season degree days

Description

The function calculates the growing season degree days (GDDs) using single/double triangulation/sine methods.

Usage

gddcal(tL, tU, tMin, tMax, tMin2 = NULL, method = NULL)

Arguments

tL

Lower temperature threshold

tU

Upper temperature threshold

tMin

Minimum temperature

tMax

Maximum temperature

tMin2

Minimum temperature for the second half day

method

GDD calculation methods (default = single sine method)

Details

gddcal is a function for calculating growing season degree days (GDDs) through four approaches popularly used in agricultural production or relevant fields.

- method = 'stri': single triangulation method
- method = 'dtri': double triangulation method (need tMin2)
- method = 'ssin': single sine method
- method = 'dsin': double sine method (need tMin2)

The default is the single sine method. i.e., if method is not specified, gddcal uses the single sine method. For two double methods ('dtri' and 'dsin'), a second half day minimum temperature needs to be specified.

Value

A numeric of growing season degree days (GDDs)

References

Zalom, F. G., P. B. Goodell, Lloyd T. Wilson, W. W. Barnett, and W. J. Bentley. (1983) "Degree-Days, the Calculation and Use of Heat Units in Pest Management." Division of Agriculture and Natural Resources, University of California. 1-11.

See Also

gddprism

Examples

## Single Triangulation Method
gddcal(55,90,50,82,'stri')
## Double Triangulation Method
gddcal(55,90,50,82,45,'dtri')
## Single Sine Method
gddcal(55,90,50,82)
gddcal(55,90,50,82,'ssin')
## Double Sine Method
gddcal(55,90,50,82,45,'dsin')