GPPFouriertest: GPPFourier test function
In GPPFourier: Calculate Gross Primary Production (GPP) from O2 Time Series

Description Usage Arguments Details Author(s) References See Also

GPPFourier test function

GPPFouriertest(x, dt = NULL, units = "days", Detrend = FALSE,
  filter = FALSE, Nfilt = NULL, circular = FALSE, sides = 2,
  filtcorrect = TRUE, trunclight = TRUE, fDL = NULL, usefft = FALSE,
  padlength = 0, fourierderive = FALSE, confine = "days", taper = FALSE,
  p = 0.1)

`x`	O2 time series from which GPP is to be calculated
`dt`	Sample time step
`units`	Time unit of sampling time step
`Detrend`	Toggle time series detrending. See GPPFourierPreprocess
`filter`	Toggle time series filtering. See GPPFourierPreprocess
`Nfilt`	Moving average filter width
`circular`	Moving average circular boundary condition (see documentation of filter())
`sides`	Moving average central or one sided (see documentation of filter())
`filtcorrect`	Logical controlling whether GPP estimate is corrected for signal falsely removed by filtering
`trunclight`	Use truncated sinusoid approximation for light&GPP. If FALSE, a sinusoid approximation is assumed
`fDL`	Relative fraction of light hours during the day
`usefft`	If FALSE the amplitude at diel freqyency is computed directly. If TRUE fft() is used to estimate amplitude at diel frequency.
`padlength`	Number of zeroes to be appended to the time series to increase frequency resolution
`fourierderive`	Calculate derivative in the frequency domain or not
`confine`	Confine time series to integer number of days or tidal cycles
`taper`	Taper the time series with spec.taper()
`p`	Fraction of the time series to be tapered at each side

This function allows to play around with the basics behind GPPFourier and GPPFourierPreprocess

trunclight controls whether GPP is assumed to evolving as a truncated sinusoid over a day or as a pure sinusoidal. This assumption determines the relation between time averaged GPP and the Fourier amplitude at diel frequency

usefft: by default GPPFourier() calculates the amplitude at diel frequency directly fft() calculates the full Fourier transform of the time series. The amplitude at diel frequency can be derived from the Fourier transform

fourierderive: if TRUE time derivation is performed in the Fourier domain by multiplying with i x omega, omega being the diurnal angular frequency. Thus the GPPFouriertest returns the amplitude at diel frequency of dx/dt. If fourierderive is FALSE, the amplitude at diel frequency of x is returned (multiplied with the factor determined by trunclight

Tom Cox <tom.cox@uantwerp.be>

Cox T.J.S. et al. (2015) 'Estimating primary production from oxygen time series: a novel approach in the frequency domain', Limnology And Oceanography:Methods 13, 529-552. DOI: 10.1002/lom3.10046

GPPFourier, GPPFourierPreprocess

GPPFourier documentation built on Sept. 22, 2017, 5:06 p.m.