Author: Krzysztof Markowicz, e-mail kmark@igf.fuw.edu.pl
Date: Last modified, Dec 2025

Device: 
Aethalometer AE-31
Instrument to measure black carbon concentration and aerosol absorption coefficient at 7 wavelengths (370 470 520 590 660 880 950 nm)
All data saved in UTC time

Structure of files:
Lev 1.0 raw data includes ASCII files:
Daily files without header. The data includes following columns:
year, month,day,hour,minute,sec, BC370, BC470,...,BC950,air flow, 
SZ370, SB370, RZ370, RB370, baypassfraction370,Atenuation370, ,...SZ950, SB370, RZ950, RB950, baypassfraction950,Atenuation950
where
BC - black carbon concentration ng/m3
SB - Sensing Beam detector output with lamps on.
SZ - Sensing Beam detector Zero offset output with lamps off.
RB - Reference Beam detector output with lamps on.
RZ - Reference beam detector Zero output with lamps off. 

Lev 1.5 matlab file.
Data from this level includes corrected optical properties.
(see processlev15aeth.m file for mode details)

Data includes data structure with following fields:
 year: year
 month: month
 day: day
 time: time [UTC]
 doy: day of year
 timeMATLAB: matlab format (number of days since Jan 1 of 0)
 lambda: wavelengths
 ATN: attenuation ceofficient
 BC: black carbon concentration
 ABS: absorption coefficient
 AE350_450: absorption Angstrom exponent 
Lev 2.0 the same structure as the Lev 1.5 data.