DynModel_driver function

DynModel_driver

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).

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 $A0$ of the dynamic model
• A1: numeric. Parameter $A1$ of the dynamic model
• E0: numeric. Parameter $E0$ of the dynamic model
• E1: numeric. Parameter $E1$ 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)

Returns

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 $xs=A0/A1\exp(-(E0-E1)/T$

Portions over the entire duration of HourTemp.

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

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)

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

Author(s)

Carsten Urbach urbach@hiskp.uni-bonn.de