Summarising Complex/Custom Time Periods

[ErikKusch]

Hi @pvanlaake,

for my work using ncdfCF, I require the summarise functionality of CFVariable objects. I wonder if this can be implemented by adjustments to this package here?

Let me describe the issue in more detail. To calculate ETCCDI (climate change indices), we need to first calculate a quantile range for each day of the year in a given base period (usually thirty years). Unfortunately, this is not as easy as looping over all days of a year (1-366) across all years. Instead, to calculate quantiles for the 1st of January, one must take all daily values belonging to January 1st as well as its two preceding and subsequent days across all years for this calculation.

I have written a function that creates these timewindows: https://github.com/Clim-Hub/ClimHub/blob/16-temporal_aggregate/R/Helper_DailyBootstrap.r (see the example and its output for how it works and what it outputs).

Any chance operations like these of a given time period specified by temporal resolution and number of steps to aggregate could be supported? How would I then summarise these windows over an epoch?

[pvanlaake]

From looking at your description, it appears that we have a function being applied over a rolling window in the "time" dimension, correct? If so, the solution should be implemented in ncdfCF, possibly with a helper function here.

[ErikKusch]

Correct!