Detrend data prior to downscaling #54
Description
It is common in downscaling to remove a given trend (e.g. temperature) before applying any statistical downscaling, then reapply the trend after downscaling. Although there are issues surrounding this methodology, it is widely used, and it would be nice to provide an option for this. It is a little tricky to think about what this might mean logistically. Does GARD need to be able to read in an entire time series (~150yrs) in order to do this. It can be done on the coarse grid, so maybe it is feasible to fit all that data in Memory(?)