Partition NEE fluxes into GPP and Reco using the daytime method.

Source: R/PartitioningLasslop10.R

Partition NEE fluxes into GPP and Reco using the daytime method.

partitionNEEGL(
  ds,
  NEEVar = if (!missing(NEEVar.s)) NEEVar.s else paste0("NEE", suffixDash, "_f"),
  TempVar = if (!missing(TempVar.s)) TempVar.s else "Tair_f",
  VPDVar = if (!missing(VPDVar.s)) VPDVar.s else "VPD_f",
  RadVar = if (!missing(RadVar.s)) RadVar.s else "Rg_f",
  suffix = if (!missing(Suffix.s)) Suffix.s else "",
  NEEVar.s,
  TempVar.s,
  VPDVar.s,
  RadVar.s,
  Suffix.s,
  ...,
  controlGLPart = partGLControl(),
  isVerbose = TRUE,
  nRecInDay = 48L,
  lrcFitter = RectangularLRCFitter()
)

Arguments

ds

dataset with all the specified input columns and full days in equidistant times

NEEVar

Variable of NEE

TempVar

Filled air or soil temperature variable (degC)

VPDVar

Filled Vapor Pressure Deficit - VPD - (hPa)

RadVar

Filled radiation variable

suffix

string inserted into column names before identifier for NEE column defaults

...

further arguments to partGLExtractStandardData(), such as PotRadVar

controlGLPart

further default parameters, see partGLControl()

isVerbose

set to FALSE to suppress output messages

nRecInDay

number of records within one day (for half-hourly data its 48)

lrcFitter

R5 class instance responsible for fitting the light response curve. Current possibilities are RectangularLRCFitter(), NonrectangularLRCFitter(), and LogisticSigmoidLRCFitter().

Value

A data.frame with columns:

  • Reco_DT_<suffix>: predicted ecosystem respiration: mumol CO2/m2/s

  • GPP_DT_<suffix>: predicted gross primary production mumol CO2/m2/s

  • <LRC>: Further light response curve (LRC) parameters and their standard deviation depend on the used LRC (e.g. for the non-rectangular LRC see NonrectangularLRCFitter_getParamNames). They are estimated for windows and are reported with the first record of the window.

  • FP_VARnight : NEE filtered for nighttime records (others NA)

  • FP_VARday : NEE filtered for daytime records (others NA)

  • NEW_FP_Temp : temperature after filtering for quality flag, degree Celsius

  • NEW_FP_VPD : vapour pressure deficit after filtering for quality flag, hPa

  • FP_RRef_Night : basal respiration estimated from nighttime (W / m2)

  • FP_qc : quality flag:

    • 0 : good parameter fit,

    • 1 : some parameters out of range, required refit,

    • 2 : next parameter estimate is more than two weeks away

  • FP_dRecPar : records until or after closest record that has a parameter estimate associated

  • FP_errorcode : information why LRC-fit was not successful or was rejected, see result of LRC_fitLRC()

  • FP_GPP2000 : predicted GPP at VPD = 0 and PAR = 2000 : a surrogate for maximum photosynthetic capacity

  • FP_OPT_VPD : list object of fitting results including iOpt and covParms

  • FP_OPT_NoVPD : list object of fitting results with fit neglecting the VPD effect

Details

The daytime-based partitioning of measured net ecosystem fluxes into gross primary production (GPP) and ecosystem respiration (Reco).

The fit to the light-response-curve is done by default using the Rectangular hyperbolic function, as in Lasslop et al. (2010).

Alternative fittings can be used by providing the corresponding subclass of LightResponseCurveFitter-class to lrcFitter argument.

see LRC_predictGPP()

References

  1. Lasslop G, Reichstein M, Papale D, et al. (2010) Separation of net ecosystem exchange into assimilation and respiration using a light response curve approach: critical issues and global evaluation. Global Change Biology, Volume 16, Issue 1, Pages 187-208