Improved parameterization of the SDWBA for estimating krill target strength

ffiffiffi 2 p =2 radians, and predictions were validated with empirical TS and total TS data at 120 kHz, and over a broad bandwidth, respectively. For general application, parameteriza- tion of the SDWBA model is improved to account explicitly for dependence among four of the model parameters: standard length of krill, number of cylinders used to describe its shape, amplitude of inter-element phase variability, and acoustic frequency. The model im- provements are demonstrated, and the uncertainty in orientation distribution of krill beneath survey vessels and its ramifications on krill biomass estimates are highlighted.