# WindowGPPFourier: Calculate GPP from O2 time series in consecutive time-windows... In GPPFourier: Calculate Gross Primary Production (GPP) from O2 Time Series

## Description

Calculate GPP from O2 time series in consecutive time-windows of prescribed length.

## Usage

 ```1 2 3 4``` ```WindowGPPFourier(x, dt = NULL, units = c("days", "hours", "mins"), Width = 14, Nblocks = floor(unclass(difftime(range(ts[, 1])[2], range(ts[, 1])[1], units = "days"))[1]/Width), fDL = NULL, phi, lambda, filtWidth = 16, ...) ```

## Arguments

 `x` Vector or dataframe containing consecutive O2 concentrations, sampled at regular intervals (time step = dt). In case of irregular time intervals, consider `resample`. When x is a data frame, time (POSIXt) must be in first column and O2 in second column; when x is a vector, dt must be provided. `dt` Sampling time step. Either a difftime object or a numerical value. When `dt` is given as a numerical value, `units` have to be provided. Can be omitted when `x` is a data frame, then `dt` is calculated from the time spacing between the first two samples. `units` Unit of sampling time step `Width` Width [days] of the time-windows for which GPP is calculated `Nblocks` Number of consecutive subsections on which to calculate GPP. By default the number of windows of Width fitting into the range of x[,1] Default the largest number of blocks ow width=Width that `fDL` Optional. Relative fraction of daylight. When `x` is a data frame, fDL is calculated with `fDLfun` `phi` Latitude of location where O2 series was recorded. Used to calculate relative fraction of light hours during the day, during which production takes place `lambda` Longitude of location where O2 series was recorded `filtWidth` [hours] Lenght of moving average filter to filter O2 series. See GPPFourierPreprocess() `...` Other parameters to be passed to `GPPFourier()`

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## Value

Average gross primary production in units of oxgen as in `x` per day.

## Author(s)

Tom Cox <tom.cox@uantwerp.be>

## References

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

`GPPFourierPreprocess`, `GPPFourier`, `GPPFourier_t`, `WindowGPPFourier.gts`, `SunRiseSet`