emission_rates.txt, an ASCII file, contains the information of the time- and altitude-dependent volcanic emission rates 
for the 2011 Nabro case study that are reconstructed by applying the "mean rule" and the "product rule" proposed in this paper. 

Header lines:
# $1 = time [s]
# $2 = altitude [km]
# $3 = emission rate (mean rule) [kg m^-1 s^-1]
# $4 = emission rate (product rule) [kg m^-1 s^-1]

1st column of data: the date and time of the emissions expressed as the number of seconds 

2nd column of data: the altitude of the emissions

3rd column of data: emission rate reconstructed by applying the "mean rule"

4th column of data: emission rate reconstructed by applying the "product rule"