Dynamic_Model {chillR}

Dynamic_Model

Description

Calculation of cumulative chill according to the Dynamic Model

This function calculates winter chill for temperate trees according to the Dynamic Model.

Chill Portions are calculated as suggested by Erez et al. (1990).

Usage

Dynamic_Model(
  HourTemp,
  summ = TRUE,
  E0 = 4153.5,
  E1 = 12888.8,
  A0 = 139500,
  A1 = 2.567e+18,
  slope = 1.6,
  Tf = 277
)

Arguments

HourTemp

Vector of hourly temperatures in degree Celsius.

summ

Boolean parameter indicating whether calculated metrics should be provided as cumulative values over the entire record (TRUE) or as the actual accumulation for each hour (FALSE).

E0

numeric. Parameter E_0 of the dynamic model

E1

numeric. Parameter E_1 of the dynamic model

A0

numeric. Parameter A_0 of the dynamic model

A1

numeric. Parameter A_1 of the dynamic model

slope

numeric. Slope parameter for sigmoidal function

Tf

numeric. Transition temperature (in degree Kelvin) for the sigmoidal function.

Value

Vector of length length(HourTemp) containing the cumulative Chill Portions over the entire duration of HourTemp.

Author(s)

Eike Luedeling

References

Dynamic Model references:

Erez A, Fishman S, Linsley-Noakes GC, Allan P (1990) The dynamic model for rest completion in peach buds. Acta Hortic 276, 165-174

Fishman S, Erez A, Couvillon GA (1987a) The temperature dependence of dormancy breaking in plants - computer simulation of processes studied under controlled temperatures. J Theor Biol 126(3), 309-321

Fishman S, Erez A, Couvillon GA (1987b) The temperature dependence of dormancy breaking in plants - mathematical analysis of a two-step model involving a cooperative transition. J Theor Biol 124(4), 473-483

Examples

weather<-fix_weather(KA_weather[which(KA_weather$Year>2006),])

hourtemps<-stack_hourly_temps(weather,latitude=50.4)

res <- Dynamic_Model(hourtemps$hourtemps$Temp)