medfate (version 0.7.4)

transp: Transpiration submodel functions

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.stomatalRegulation calculates profit maximization for all time steps in a day, starting from stand description, soil description and meteorological input. 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, type, 
                          Gwmin, Gwmax, kleafmax = NA)
transp.stomatalRegulation(x, soil, meteo, day,
                             latitude, elevation)
transp.stomatalRegulationPlot(x, soil, meteo, day, timestep, 
                              latitude, elevation)

Arguments

supplyFunction

Water supply function (see hydraulics.supplyFunctionNetwork).

photosynthesisFunction

Function returned by photo.photosynthesisFunction().

type

Optimization type (1,2 or 3).

Gwmin, Gwmax

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

kleafmax

Maximum leaf hydraulic conductance (flow per pressure drop).

x

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

soil

An object of class soil.

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

Elevation above sea level (in m).

Value

Values returned for each function are:

• transp.profitMaximization: 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).

• transp.stomatalRegulation: A list whose elements correspond to cohorts. Each element has the following subelements:

  • supply: Supply function (see hydraulics.supplyFunctionNetwork).

  • photoSunlit, photoShade: Photosynthesis function for sunlit and shade leaves and for each time step (see photo.leafPhotosynthesisFunction).

  • PMSunlit, PMShade: Profit maximization for sunlit and shade leaves and each time step (see transp.profitMaximization).

Details

Details of the transpiration submodel are given in a vignette.

References

Sperry, J. S., M. D. Venturas, W. R. L. Anderegg, M. Mencuccini, D. S. Mackay, Y. Wang, and D. M. Love. 2016. Predicting stomatal responses to the environment from the optimization of photosynthetic gain and hydraulic cost. Plant Cell and Environment.

See Also

hydraulics.supplyFunctionNetwork, biophysics.leafTemperature, photo.photosynthesis, spwb

Examples

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

#Load example plot plant data
data(exampleforest)

#Default species parameterization
data(SpParamsMED)

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

#Initialize control parameters
control = defaultControl()
#Switch to 'Complex' transpiration mode
control$transpirationMode="Complex"

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

transp.stomatalRegulationPlot(x2, examplesoil2, examplemeteo, day=100, timestep = 12,
                              latitude = 41.82592, elevation = 100)
# }