Sediment echosounder raw data (Atlas Parasound P70) of RV SONNE during cruise 296/2 in the Golfo Almirante Montt (Chile)

Parametric sediment echosounder (Teledyne Atlas PARASOUND P70) data were recorded during RV SONNE cruise SO296/2, which took place in the Golfo Almirante Montt (Chile) between February 3rd and 8th 2023, to image the internal sediment structures of the subsurface. The aim of the investigations of the project MAPUCHE was to gain a comprehensive understanding of recent and past biogeochemical processes in the fjord by combining biogeochemical, oceanographic, and paleoceanographic investigations.The hull-mounted narrow-beam echosounder system utilizes the nonlinear interference of two slightly different primary frequencies (PHF: 18-20 kHz and 22 – 24 kHz) at high signal amplitude to generate two parametric secondary frequencies with improved signal-to-noise ratio, which results in high vertical and lateral resolution. The aperture angle was 4.5° and the resulting footprint size was 7% of the water depth. The secondary low frequency (SLF) can be set to 0.5 – 7 kHz and the secondary high frequency (SHF) to 40 – 42 kHz. During SO296/2, 18 kHz for the PHF and 4 kHz for the SLF was chosen with a transmission voltage of 140 V.