I am trying to extract data from one data set (contains water quality data -- chlorophyll, dissolved oxygen, temp, etc), using information from another data set that contains tidal information (low tide times).
Background: It has recently come to my attention that due to hydrodynamics it will be best to only look at WQ data points measured at low tide, when I had previously just taken the daily average.
Is there a way I can extract specific WQ data based on if it aligns with date/time of the tidal data??? Caveats -- the times might not match up exactly, WQ data was measured every 15 minutes so I need the closest point(s) to the low tide time.