DOI: 10.15493/dea.mims.09962023
title: Processed underway Thermosalinograph (TSG) observations from the Integrated Ecosystem Programme: Southern Benguela (IEP:SB) on the Algoa Voyage 274, August 2021

description: 6-second resolution processed Thermosalinograph (TSG) data collected between 22 August and 30 August 2021 during the Integrated Ecosystem Programme: Southern Benguela (IEP:SB) on the RS Algoa Voyage 274
description: Here we present the 6-second resolution processed Thermosalinograph (TSG) data collected between 22 August and 30 August 2021 during the Integrated Ecosystem Programme: Southern Benguela (IEP:SB) on the RS Algoa Voyage 274. A SeaBird SBE45 TSG is used to opportunistically collect underway near-surface temperature and conductivity measurements during research and monitoring cruises. Water is continuously pumped to the TSG from an intake located in the hull of the vessel, and the observations are continuously interfaced with navigational information. A temperature sensor close to the intake provides temperature measurements of the incoming water (T1). The temperature of the water inside the conductivity cell (T2) is used to accurately compute salinity (S) from the conductivity measurements (C). This is a long-term monitoring line conducted off the coast of Kleinsee, Namaqualand, Elands/St Helena Bay and Scarborough on the west coast of South Africa. The IEP:SB in 2013 consolidated a long-term, multi-decadal time-series (from 1951 onward) of information for this important region and has continued monitoring in the form of the IEP:SB. The programme is a multi-disciplinary, collaborative and capacity building platform undertaking relevant science, including updating technology, with the aim to develop ecosystem indicators that can be used to effectively monitor and understand the Southern Benguela. These include physical, chemical, planktonic, microbial, seabird, marine mammal, benthic and pollution (plastic) ecosystem indicators as required by ecosystem-based management regarding the following priorities: ocean warming, ocean acidification, trophic functioning, pollution and water quality. It is on-going monitoring programme.
description: The SeaBird SBE45 Thermosalinograph (TSG) is used on the RS Algoa for the collection of underway near-surface temperature and conductivity measurements. The underway seawater is obtained from a depth of 5m below the surface and pumped through the TSG. Data is collected using the most recent SeaBird (SBE) SeaSave software and processed using the most recent SBE data processing software. The software was set to record data at 6 second intervals for the duration of the cruise, between 22 August and 30 August 2021. Data was collected in the southern part of the Benguela Current Large Marine Ecosystem (BCLME) region on the west coast of South Africa. Unreliable TSG measurements can result from a variety of problems encountered during the cruises, including insufficient water flow, extreme air bubbling during severely adverse weather conditions, debris trapped in the system, or a variety of electronic failures. Detailed visual inspection of the ship trajectory and TSG measurements, as well as comparisons with other concurrent and historical near-surface measurements, and expert knowledge of local conditions, were used to identify and remove all unreliable data.