Utah Model

Quantifies the chill accumulation by means of converting temperatures to chill-units.

utah_model(x, total = TRUE)

Arguments

x	Vector containing temperature values (Celsius-degree).
total	TRUE Shows the total value of accumulation, FALSE shows the value of chill-unit for each temperature (TRUE is default).

Value

The function returns values the chill-units for each temperature of vector (Total = FALSE), or returns the chill-units accumulation (Total = TRUE).

Details

The model is based on chill-units, where 1 chill-unit is when the tree is exposure between 2.4°C and 9.1°C, being the optimum temperature 6°C . When the temperature is between 9.1°C and 12.4°C, the chill-unit is 0.5. The chill-units accumulation is 0 when occurs temperature below 1.4 and between 12.5°C and 15.9°C. When the temperature is between 16°C and 18°C, the chill-unit is -0.5. When the temperature is above 18°C, the chill-unit is -1.

References

Richardson, E, A. et al. 1974. "A Model for Estimating the Completation of Rest for 'Redhaven' and 'Elberta' Peach Trees". Research Reports & Notes.

Examples

x <- rnorm(500, 5, 3)
utah_model(x)
#> [1] 396.5
utah_model(x, FALSE)
#>   [1] 1.0 1.0 0.5 1.0 0.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.0 0.0 1.0 0.0
#>  [19] 0.0 1.0 1.0 1.0 0.0 0.5 1.0 0.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
#>  [37] 0.5 1.0 1.0 1.0 1.0 1.0 1.0 0.0 1.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0
#>  [55] 1.0 1.0 0.0 0.0 0.5 1.0 0.0 1.0 1.0 0.5 0.0 1.0 0.0 1.0 1.0 1.0 1.0 0.5
#>  [73] 1.0 1.0 1.0 1.0 0.0 0.0 0.5 0.5 0.0 1.0 0.0 1.0 1.0 0.0 1.0 1.0 0.5 1.0
#>  [91] 1.0 1.0 0.0 0.5 0.0 1.0 0.5 1.0 0.0 0.5 1.0 1.0 0.0 0.5 1.0 1.0 1.0 1.0
#> [109] 1.0 1.0 0.5 1.0 1.0 1.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0
#> [127] 1.0 1.0 0.5 1.0 1.0 0.5 0.5 0.5 1.0 0.5 0.5 0.5 1.0 1.0 0.5 1.0 1.0 0.5
#> [145] 1.0 0.5 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 1.0 1.0
#> [163] 1.0 0.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 1.0 0.0 1.0 0.5 0.0
#> [181] 1.0 1.0 1.0 1.0 0.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 0.5 1.0 1.0
#> [199] 0.5 1.0 1.0 1.0 1.0 0.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 0.0 1.0
#> [217] 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 0.5 1.0 0.5 0.5 1.0 0.5 1.0 1.0
#> [235] 0.5 1.0 0.5 1.0 1.0 0.5 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 0.5 1.0 1.0 1.0
#> [253] 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 0.5 0.5 0.0 1.0 0.5
#> [271] 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0
#> [289] 1.0 1.0 0.0 1.0 1.0 0.0 1.0 1.0 1.0 0.0 1.0 0.5 1.0 1.0 0.0 0.0 0.5 1.0
#> [307] 1.0 1.0 1.0 0.0 1.0 0.0 1.0 1.0 0.0 0.0 0.5 1.0 1.0 1.0 1.0 1.0 0.0 0.0
#> [325] 1.0 1.0 1.0 1.0 1.0 1.0 0.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0
#> [343] 0.0 1.0 0.0 1.0 1.0 1.0 0.5 1.0 1.0 0.5 0.0 1.0 1.0 1.0 0.0 1.0 1.0 1.0
#> [361] 0.5 0.0 1.0 0.5 1.0 0.5 0.0 0.0 0.0 1.0 0.5 0.0 1.0 1.0 1.0 1.0 0.5 0.0
#> [379] 0.0 1.0 0.0 0.5 1.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 1.0 1.0
#> [397] 0.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 0.5 0.5 0.5 1.0 1.0 1.0
#> [415] 1.0 1.0 1.0 0.0 0.5 0.5 0.5 1.0 1.0 1.0 0.5 1.0 1.0 0.5 1.0 1.0 1.0 0.0
#> [433] 0.0 1.0 1.0 1.0 0.0 1.0 1.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
#> [451] 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 0.0 1.0 0.0 1.0 1.0 1.0
#> [469] 1.0 0.5 0.0 0.5 1.0 0.5 1.0 1.0 1.0 0.5 1.0 1.0 1.0 0.5 1.0 1.0 1.0 1.0
#> [487] 1.0 0.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0