Units of tilt

[signehl]

In the conversion of tilt from voltage to degrees (in the function getTiltDegrees on line 304 in L0toL1.py), the tilt is divided by 10:
tilt = tilt / 10

Why is this? In the logger programs (at least PROMICE_V2_2022_V1_2.CR1), the tilt is written out in V10^-2, so I assume it is not to go from V10^-2 to V as you would then divide by 100?

[signehl]

I cannot find the unit of the calibration coefficients anywhere in the PROMICE ESSD paper or i pypromice. But the answer must be there?

I am dealing with this issue since the unit in the GlacioBasis Zackenberg ZAC_L logger program is in mV and not V*10^-2 as newer versions of the logger program.

[PennyHow]

In the conversion of tilt from voltage to degrees (in the function getTiltDegrees on line 304 in L0toL1.py), the tilt is divided by 10:
tilt = tilt / 10

Tilt is directly lifted from the previous IDL processing scripts here:

https://github.com/GEUS-Glaciology-and-Climate/AWS_v3/blob/cccd8a40a2ffc619d00595c6436386e58e1918ac/AWSdataprocessing_v3.pro#L389

As shown in pypromice here:

pypromice/src/pypromice/process/L0toL1.py

Line 304 in e4ff5ed

tilt = tilt / 10

There is no documentation on the IDL scripts about why we do this, but we kept it in order to produce the same output.

I cannot find the unit of the calibration coefficients anywhere in the PROMICE ESSD paper or i pypromice. But the answer must be there?

This is where we apply the calibration coefficients in pypromice:

pypromice/src/pypromice/process/L0toL1.py

Lines 48 to 55 in e4ff5ed

	if hasattr(ds, 'dsr_eng_coef'):
	ds['dsr'] = (ds['dsr'] * 10) / ds.attrs['dsr_eng_coef'] # Convert radiation from engineering to physical units
	if hasattr(ds, 'usr_eng_coef'): # TODO add metadata to indicate whether radiometer values are corrected with calibration values or not
	ds['usr'] = (ds['usr'] * 10) / ds.attrs['usr_eng_coef']
	if hasattr(ds, 'dlr_eng_coef'):
	ds['dlr'] = ((ds['dlr'] * 10) / ds.attrs['dlr_eng_coef']) + 5.67E-8*(ds['t_rad'] + T_0)**4
	if hasattr(ds, 'ulr_eng_coef'):
	ds['ulr'] = ((ds['ulr'] * 10) / ds.attrs['ulr_eng_coef']) + 5.67E-8*(ds['t_rad'] + T_0)**4

Again, not sure what units these are provided in but perhaps @robertfausto or Allan knows? The calibration certificates for each instrument should come back to GEUS with units surely? If the units differ for logger program PROMICE_V2_2022_V1_2.CR1 then we should be able to incorporate this into pypromice