DynModel_driver {chillR}

DynModel_driver

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

DynModel_driver(
  temp,
  times,
  A0 = 139500,
  A1 = 2.567e+18,
  E0 = 4153.5,
  E1 = 12888.8,
  slope = 1.6,
  Tf = 4,
  deg_celsius = TRUE
)

Arguments

temp

Vector of temperatures.

times

numeric vector. Optional times at which the temperatures where measured, if not given, hourly temperatures will be assumed

A0

numeric. Parameter A_0 of the dynamic model

A1

numeric. Parameter A_1 of the dynamic model

E0

numeric. Parameter E_0 of the dynamic model

E1

numeric. Parameter E_1 of the dynamic model

slope

numeric. Slope parameter for sigmoidal function

Tf

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

deg_celsius

boolean. whether or not the temperature vector and the model temperature parameters are in degree Celsius (Kelvin otherwise)

Details

This function gives idential results as Dynamic_Model for hourly temperature data, returns more details but is also a bit slower in the R code version

Value

List containint four vectors of length(temp) with elements x is the PDBF, y the accumulated chill, delta the chill portions and xs, which is x_s=A_0/A_1\exp(-(E_0-E_1)/T) Portions over the entire duration of HourTemp.

Author(s)

Carsten Urbach <[e-mail]>

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$Year>2006),])
hourtemps<-stack_hourly_temps(weather,latitude=50.4)
res2 <- DynModel_driver(temp=hourtemps$hourtemps$Temp)