In cdmuir/tealeaves: Solve for Leaf Temperature Using Energy Balance

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

In some cases, users may not wish to provide a parameter value, but rather have a value calculated based on other parameters. Currently, the only parameters that can be provided as functions are:

nu_constant in constants()
sh_constant in constants()
T_sky in enviro_par()

I plan to make more of these in the future, but I'll briefly demonstrate how one would change the T_sky function. The default function from Okajima et al. (2012), which was hard-coded in versions 1.0.0 and 1.0.1, is:

library(tealeaves)

leaf_par   <- make_leafpar()   # leaf parameters
enviro_par <- make_enviropar() # environmental parameters
constants  <- make_constants() # physical constants

enviro_par$T_sky

Let's change it simply be the air temperature (T_air). The current requirements for this function as of version 1.0.2 are:

It must take pars as the only argument, where pars is the concatenated set of leaf (leaf_par()) and environmental parameters (enviro_par())
It must return T_sky in units K. You can ensure this by using units::set_units(., K)

enviro_par <- make_enviropar(
  replace = list(T_sky = function(pars) {pars$T_air})
)
enviro_par$T_sky

T_leaf <- tleaf(leaf_par, enviro_par, constants, quiet = TRUE)

knitr::kable(T_leaf)