EBAS reader: Handle time step sizes that differ over the provided time series

[jgriesfeller]

This concerns all types of EBAS readers...

From EMEP report 2022:

Precipitation:
Amberd looks VERY high

Remaining issue: Når jeg ser på Amberd, så er måleperiodene totalt irregulære. Det varierer mellom en halv dag og flere dager 
(feks 10 jan fra 10:20 til 19:10, og 4.3 kl 7 til 9.3 kl 7). Dette klarer ikke Pyaerocom å håndtere (ihvertfall ikke enda), 
så disse dataene må vi kaste ut.

• The first discussion needs to be about how we want pyaerocom to handle this?
• What to do if not all time steps fit?

How it is today (to my best knowledge):
Because the colocation can't handle time colocation with start and stop times. it has to assume a certain time step size and do the colocation on the middle points. We do accept small deviations from the time step sizes we have (details are here:

pyaerocom/pyaerocom/tstype.py

Lines 22 to 42 in b06cfde

	class TsType:
	VALID = TS_TYPES
	VALID_ITER = VALID[:-1]
	FROM_PANDAS = PANDAS_FREQ_TO_TS_TYPE
	TO_PANDAS = TS_TYPE_TO_PANDAS_FREQ
	TO_NUMPY = TS_TYPE_TO_NUMPY_FREQ
	TO_SI = TS_TYPE_TO_SI
	TS_MAX_VALS = {
	"minutely": 360, # up to 6hourly
	"hourly": 168, # up to weekly
	"daily": 180, # up to 6 monthly
	"weekly": 104, # up to ~2yearly
	"monthly": 120,
	} # up to 10yearly
	# "monthly": "days" below is because each month does not have the same number of days
	# netcdf does time calculation for you given starting day and days past (CF convention)
	TSTR_TO_CF = {"hourly": "hours", "daily": "days", "monthly": "days"}
	TOL_SECS_PERCENT = 5

But the devil might like in the details of the reader implementations

[lewisblake]

I would say we should ask the modelers how they want the comparison done and then we implement that rather than us coming up with a solution which they might not be satisfied with. If we are to include this data, what should we do with it? If no solution is given, then it is fair to throw out this station.

[jgriesfeller]

@lewisblake agreed. The "probblem" right now is that the station is not ignored automatically. (Yes, I should have mentioned that above)
Pyaerocom's focus is to get as much data as possible.

[lewisblake]

To be discussed: https://github.com/metno/AeroToolsIssues/issues/80