Coastal water quality, greenhouse gas and weather monitoring data collected utilizing the mobile and freely scalable Coastrider platform for automated in situ measurements. The sensor data have been validated and, if necessary, calibrated through accredited laboratory analyses. The modular Coastrider platform consists of two parallel and identical sensor assemblages. One of them is used for lateral underway (flow-through) surface water (0.5 m) surveys, while the other one is primarily employed for stationary vertical profiling from the surface down to 120 m depth. The surface water data are logged, on average, at 50-m intervals, while the vertical profiles are recorded with 1-m resolution. The principal and permanently applied components of the Coastrider platform include the EXO2-multiparameter sonde (Xylem Inc, USA) equipped with sensors for total algae (chlorophyll a/phycocyanin), turbidity, fluorescent dissolved organic matter, temperature/conductivity, pH and oxygen, and optionally for rhodamine WT. The EXO-Handheld unit has been used for geospatial referencing (datetime- and GPS-stamps) and for recording air pressure. The partial pressure of carbon dioxide is measured by the CO2 Pro CV sensor (Pro Oceanus Systems Inc, Canada) and that of methane by the Mini CH4 sensor (Pro Oceanus Systems Inc, Canada). Air humidity, air temperature and photosynthetically active radiation (PAR) are measured by various Hobo-loggers (Onset Computer Corp., USA). Occasionally, additional data have been collected with supplementary sensors such as the LISST laser diffraction particle size analyzer (Sequoia Scientific Inc, USA) for measuring suspended particle size and concentration. The principal data have been collected in the coastal waters of SW Finland since 2018. Currently, the continuously expanding data set consist of approximately 1,000,000 observations for each variable, spanning six ice-free (growing) seasons and coastal waters between the city of Uusikaupunki in NW and the city of Sipoo in SE with high spatiotemporal resolution and coverage. In addition to the directly measured variables, the data set consists of tens of variables whose values can be reliably calculated or derived from the directly measured ones. The derived variables include salinity and the concentrations of total nitrogen (TN), phosphorus (TP) and organic carbon (TOC).

2024