This page describes the parameters that can be used to customize the Jönsson model. The model was developed by Jonsson2011;textualbarrks. Look here to find out how to apply the model.
The date, when the degree days start to sum up ('MM-DD').
Base temperature to calculate degree days to trigger the onset.
Degree days that are required to trigger the onset of
infestation. Additionally, the maximum temperature must exceed tfly.
Minimum temperature that beetles need to fly.
Base temperature to calculate degree days for development.
Lower/upper limit of degree days that are required for a generation to fully develop
Share in total development when the egg development starts and the juvenile beetle's development ends respectively. Usable if the development below/above these thresholds should account for mating, oviposition etc.
The beetles are considered to be in
white stages (egg, larva, pupa) if their development exceeds dev_mortal_min
and subceeds dev_mortal_max. During these stages, the beetles could die
due to a mortality event. NULL means that no lower/upper threshold is
defined.
Date when the model ends (no further development will be modeled).
When the daylength falls below daylength_dia
and the average daily temperature falls below tdia_min, diapause
will be initiated. The default value for the critical daylength was set to
19.3 hours according to Schroeder2017;textualbarrks who
examined the photoperiodic diapause induction in Sweden. If the model is used
for other regions, this value should be adjusted.
In barrks, model() is used to customize a model. The following code
illustrates which parameters are available for the Jönsson model and specifies their
default values.
model("joensson", # ==== onset ====
dd_onset_start_date = '01-01',
dd_onset_base = 5,
dd_onset_threshold = 120,
# ==== onset + development ====
tfly = 20,
# ==== development ====
dd_development_base = 5,
dd_total_dev_lower = 625,
dd_total_dev_upper = 750,
dev_start = 0,
dev_end = 1,
dev_mortal_min = 0,
dev_mortal_max = 1,
model_end_date = '12-31',
# ==== diapause ====
daylength_dia = 19.3,
tdia_min = 15
)
model(), phenology(), model.joensson.apply
Other model customizations:
model.bso.customize,
model.chapy.customize,
model.lange.customize,
model.phenips.customize,
model.phenips_clim.customize,
model.rity.customize