make_seasLAI: Construct the seasonal course of leaf area index from...

In LWFBrook90R: Simulate Evapotranspiration and Soil Moisture with the SVAT Model LWF-Brook90

Construct the seasonal course of leaf area index from parameters

Description

A daily sequence of leaf area index is derived from maximum and minimum values, dates and shape parameters using different methods.

Usage

make_seasLAI(
  method = "b90",
  year,
  maxlai,
  winlaifrac = 0,
  budburst_doy = 121,
  leaffall_doy = 279,
  emerge_dur = 28,
  leaffall_dur = 58,
  shp_optdoy = 220,
  shp_budburst = 0.5,
  shp_leaffall = 10,
  lai_doy = c(1, 121, 150, 280, 320, 365),
  lai_frac = c(0, 0, 0.5, 1, 0.5, 0)
)

Arguments

method	Name of method for generating the sequence. Must be one of "b90", "linear", "Coupmodel".
year	Vector of years to be returned.
maxlai	Maximum leaf are index.
winlaifrac	Fraction of maxlai during winter (ignored when method = 'linear').
budburst_doy	Budburst day of year (ignored when method = 'linear').
leaffall_doy	Day of year when leaf fall begins (ignored when method = 'linear').
emerge_dur	Number of days from budburst until maximum leaf area index is reached.
leaffall_dur	Number of days until minimum leaf are index is reached.
shp_optdoy	Day of year when optimum value is reached (required when method = "Coupmodel").
shp_budburst	Shape parameter for the growth phase (required when method = "Coupmodel").
shp_leaffall	Shape parameter growth cessation (required when method = "Coupmodel").
lai_doy	Integer vector of days of years.
lai_frac	Vector of values of fractional leaf area index corresponding to lai_doy (required when method = "linear").

Value

A vector of daily lai values covering the years specified.

Examples

# Intraannual courses of leaf area index
lai_b90 <- make_seasLAI(method = "b90",
                       year = 2001,
                       maxlai = 5,
                       winlaifrac = 0,
                       budburst_doy = 121,
                       leaffall_doy = 280,
                       emerge_dur = 15,
                       leaffall_dur = 30)

lai_doy <- c(1,110,117,135,175,220,250,290,365)
lai_frac <- c(0.1,0.1,0.5,0.7,1.2,1.2,1.0,0.1,0.1)
lai_linear <- make_seasLAI(method = "linear",
                          year = 2001,
                          maxlai = 5,
                          lai_doy = lai_doy,
                          lai_frac = lai_frac)

lai_coupmodel <- make_seasLAI(method = "Coupmodel",
                             year = 2001,
                             maxlai = 5,
                             winlaifrac = 0.1,
                             budburst_doy = 110,
                             leaffall_doy = 280,
                             shp_optdoy = 180,
                             shp_budburst = 0.5,
                             shp_leaffall = 5)

plot(lai_b90, type = "n", xlab = "doy", ylab = "lai [m²/m²]", ylim = c(0,6))
lines(lai_b90, col ="green",lwd = 2,)
lines(lai_linear, col ="red",lwd = 2)
lines(lai_coupmodel, col ="blue",lwd = 2)

# incorparating between-year variability
years <- 2001:2003
lai <- make_seasLAI(method = "Coupmodel",
                   year = years,
                   maxlai = c(4,6,5),
                   budburst_doy = c(100,135,121),
                   leaffall_doy = 280,
                   shp_budburst = c(3,1,0.3),
                   shp_leaffall = 3,
                   shp_optdoy =c(210,180,240) )

dates <- seq.Date(as.Date("2001-01-01"), as.Date("2003-12-31"), by = "day")
plot(dates,lai, col = "green", ylab = "lai [m²/m²]",
     type ="l", xlab = "", lwd = 2)

LWFBrook90R documentation built on June 8, 2025, 11:20 a.m.