calculate_longterm_leaf: leaf-to-ambient CO2 ratio (chi_o) and Water use efficiency...
In bgctw/etpart: Partitioning evapotranspiration into transpiration and evaporation

Description Usage Arguments Details Value References Examples

Calculate long-term effective "internal" leaf-to-ambient CO2 (chi_o) and Water use efficiency (WUE_o)

calculate_longterm_leaf(
  data,
  altitude,
  C = config$C,
  config = priego_config(),
  constants = etpart_constants()
)

`data`	Data.frame with columns GPP: photosynthesis (umol CO2 m-2 s-1) VPD: vapor pressure deficit (kPa). Tair: air temperature (deg C).
`altitude`	numeric value defining elevation (m).
`C`	Empirical coeficient for C3 species. (see Wang et al., 2017; Plant Nature)
`config`	configuration (`priego_config`) with entry C for default of argument C
`constants`	physical constants, see `etpart_constants`

the following metrics are calculated:

chi_o:

logistic_chi_o = 0.0545*(Tair_g-25)-0.58*log(VPD_g)-0.0815*Z+C

chi_o <- exp(logistic_chi_o)/(1+exp(logistic_chi_o))

WUE_o:

WUE_o <- (390*(1-chi_o)*96)/(1.6*VPD_g)*0.001

Tair_g and VPD_g are calculated based on the mean value of the growing period. The growing period is estimated as those periods over the 85 quantile of GPP.

list with numeric entries:

`chi_o`	long-term effective "internal" leaf-to-ambient CO2 (unitless)
`WUE_o`	long-term effective Water use efficiency (umolCO2 mmol-1)

Wang, H., I. C. Prentice, et al., (2017), Towards a universal model for carbon dioxide uptake by plants, Nature Plants, 3(9), 734-741.

Reichstein, M., et al. (2005), On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm, Global Change Biology, 11(9), 1424-1439.