medfate (version 2.2.1)

transp_stomatalregulation: Stomatal regulation

Description

Set of high-level functions used in the calculation of stomatal conductance and transpiration. Function transp_profitMaximization calculates gain and cost functions, as well as profit maximization from supply and photosynthesis input functions. Function transp_stomatalRegulationPlot produces a plot with the cohort supply functions against water potential and a plot with the cohort photosynthesis functions against water potential, both with the maximum profit values indicated.

Usage

transp_profitMaximization(supplyFunction, photosynthesisFunction, Gswmin, Gswmax, 
                          gainModifier = 1.0, costModifier = 1.0, costWater = "dEdP")
transp_stomatalRegulationPlot(x, meteo, day, timestep, 
                              latitude, elevation, slope = NA, aspect = NA,
                              type="E")

Arguments

supplyFunction

Water supply function (see hydraulics_supplyFunctionNetwork).

photosynthesisFunction

Function returned by photo_photosynthesisFunction().

Gswmin, Gswmax

Minimum and maximum stomatal conductance to water vapour (mol<U+00B7>m-2<U+00B7>s-1).

gainModifier, costModifier

Modifiers (exponents) of the gain and cost functions defined in Sperry et al. (2017).

costWater

Cost water function, either "dEdP" (default) or "kterm" (experimental).

x

An object of class spwbInput built using the 'Sperry' transpiration mode.

meteo

A data frame with daily meteorological data series:

• DOY: Day of the year (Julian day).

• Precipitation: Precipitation (in mm).

• MeanTemperature: Mean temperature (in degrees Celsius).

• MinTemperature: Minimum temperature (in degrees Celsius).

• MaxTemperature: Maximum temperature (in degrees Celsius).

• MinRelativeHumidity: Minimum relative humidity (in percent).

• MaxRelativeHumidity: Maximum relative humidity (in percent).

• Radiation: Solar radiation (in MJ/m2/day).

• WindSpeed: Wind speed (in m/s). If not available, this column can be left with NA values.

day

An integer to identify a day within meteo.

timestep

An integer between 1 and ndailysteps specified in x (see defaultControl).

latitude

Latitude (in degrees).

elevation, slope, aspect

Elevation above sea level (in m), slope (in degrees) and aspect (in degrees from North).

type

A string with plot type, either "E" (transpiration flow), "Ag" (gross photosynthesis), "An" (net photosynthesis), "Gsw" (stomatal conductance to water vapour), "T" (temperature) or "VPD" (leaf vapour pressure deficit).

Value

Function transp_profitMaximization returns a list with the following elements:

• Cost: Cost function [0-1].

• Gain: Gain function [0-1].

• Profit: Profit function [0-1].

• iMaxProfit: Index corresponding to maximum profit (starting from 0).

References

Sperry, J. S., M. D. Venturas, W. R. L. Anderegg, M. Mencuccini, D. S. Mackay, Y. Wang, and D. M. Love. 2017. Predicting stomatal responses to the environment from the optimization of photosynthetic gain and hydraulic cost. Plant Cell and Environment 40, 816-830 (doi: 10.1111/pce.12852).

See Also

transp_transpirationSperry, hydraulics_supplyFunctionNetwork, biophysics_leafTemperature, photo_photosynthesis, spwb_day, plot.spwb_day

Examples

# NOT RUN {
#Load example daily meteorological data
data(examplemeteo)

#Load example plot plant data
data(exampleforestMED)

#Default species parameterization
data(SpParamsMED)


#Initialize soil with default soil params (2 layers)
examplesoil = soil(defaultSoilParams(2))

#Initialize control parameters
control = defaultControl(transpirationMode="Sperry")

#Initialize soil with default soil params (2 layers)
examplesoil2 = soil(defaultSoilParams(2))

#Initialize input
x2 = forest2spwbInput(exampleforestMED,examplesoil2, SpParamsMED, control)

# Stomatal VPD curve and chosen value for the 12th time step at day 100
transp_stomatalRegulationPlot(x2, examplemeteo, day=100, timestep = 12,
                              latitude = 41.82592, elevation = 100, type="VPD")
# }