N_sigma_bs
N_sigma_bs is an analysis variable useful for the purposes of biomass estimation.
Let D be the domain over which the sample mean is to be calculated.
Then N_sigma_bs is calculated as follows:
Where:
N = Number of fish in the domain D (-)
sbs = Expected backscattering cross-section of an individual fish in the domain D (m2)
sv = The linear mean Sv for all samples in the domain D (m2/m3)
V = the integration volume (m3)
and
Sv_mean and Volume_integration are the respective analysis variables with those names.