GranierConversions: Performs Granier-relevant data transformation

In bmcnellis/sapflux: Analyze Sapflux Traces

Description

Conversion here converts raw/partially converted data to a per-tree flow index, in three steps:

1. Convert raw voltage data to temperature differentials

2. Perform automatic dT zeroing

3. Apply the Granier calibration. Defaults to Granier (1987): u = 0.000119 * K ^ 1.231 . Other calibrations supported.

Usage

GranierConversions(flux, stop_at = "flux_density", multiplier = 25,
  refT = NULL, zero_method = "omit_NTE", index_eqn = NULL, JIT = FALSE,
  window = c(2300, 300))

GranierEqn(K)

Arguments

flux	'flux' class object
stop_at	This is a hack that should be ignored.
multiplier	Alternative to refT - simple voltage multiplier
refT	Reference probe temperature, calculate Seebeck coeff
zero_method	Method to use for temperature-zeroing routine
index_eqn	Equation to pass to generate the 'flux index'
JIT	TRUE/FALSE, use JIT/cmpfun() from package 'compiler' to try to speed up the zeroing function?
...	Further arguments.

Value

Returns the 'flux' object with data represented as a transpiration 'density' at the point of measurement, in units of centimeters of H2O per hour. Also updates metadata, when appropriate, as well as the datatype and output logs.

Functions

• GranierEqn: Granier's original 1987 conversion factor

See Also

Other zero: ByColumnOmitNTE, VPDThresholdNTE

Other zero: ByColumnOmitNTE, VPDThresholdNTE

Examples

# Custom Granier calibration:
eqn <- function(x) {
  # 'x' is equivalent to 'K' in Granier (1987)
    a <- 0.000224
    b <- 1.55
    u <- a * (K ^ b)
    return(u)
}
# Added a refT to account for lower temperatures at e.g. boreal study site
data <- GranierConversions(flux = flux, zero.method = "Omit.NTE",
                           index.eqn = eqn, refT = 7)

bmcnellis/sapflux documentation built on May 12, 2019, 10:27 p.m.