OperativeT: Calculates Operative Temperature

In ilyamaclean/microctools: Various worker functions for microclimc package

Calculates Operative Temperature

Description

The function OperativeT calculates the humid operative temperature of an organism

Usage

OperativeT(
  Rabs,
  gH,
  gV,
  tair,
  ea,
  pk = 101.3,
  surfwet = 1,
  em = 0.97,
  fluxother = 0,
  method = "iter"
)

Arguments

Rabs	Absorbed long- and shortwave radiation as returned by Radbs() (W / m^2)
gH	conductance for heat (mol / m^2 / sec)
gV	conductance for vapour (mol / m^2 / sec)
tair	temperature of air surrounding organism (deg C)
ea	Vapour pressur eof air surrounding organism (kPa)
pk	Atmospheric pressure (kPa)
surfwet	Fraction of surface area acting like a free‐water surface
em	thermal emissivity
fluxother	Fluxe sother than radiation, sensible and latent heat operating on organism (W / m^2). Positive if warming organism (e.g. metabolism), negative if leaving organism (e.g. ground heat flux)
method	one of iter, Penman or PenMon (see details)

Details

The Humid Operative Temperature is the temperature at which all fluxes operating on the organism sum to zero. If method = iter, this temperature is calaculated iteratively and the inputs must be single values rather than vectors. If method = open, radiation emmited is linearized by computing radiative conductance, and the Penman linearization for latent heat flux is used. The results obtained are similar, though not quite as accurate as those obtained using iter.If method = PenmMon, the Penman-Monteith equation is used, i.e. it is assumed that the temperature and humidity of the environment are influenced by evapotransporation from the organism, such that humidity increases and the air cools. In consequence, there is less latent heat flux, and the operative temperatures are higher.

Value

Humid Operative Temperature of organism - i.e. steady-state temperature of organism (deg C)

Examples

Rabs <- c(200:700)
OT1 <- 0
for (i in 1:length(Rabs)) OT1[i] <- OperativeT(Rabs[i], 0.3, 0.2, 15, 1.2, method = "iter")
OT2 <- OperativeT(Rabs, 0.3, 0.2, 15, 1.2, method = "open")
OT3 <- OperativeT(Rabs, 0.3, 0.2, 15, 1.2, method = "PenmMon")
plot(OT1 ~ Rabs, type = "l", ylim = c(0,40), lwd = 2)
par(new=T)
plot(OT2 ~ Rabs, type = "l", ylim = c(0,40), col = "blue", lwd = 2)
par(new=T)
plot(OT3 ~ Rabs, type = "l", ylim = c(0,40), col = "red", lwd = 2)

ilyamaclean/microctools documentation built on Jan. 25, 2023, 5:29 a.m.