The land ocean aquatic continuum (LOAC) consists of soils, streams, rivers, groundwater, lakes, wetlands, estuaries, and shelf seas and plays a key role in the global carbon (C) cycle. Inland waters receive ∼5.1 Pg C per year from land, which is ∼55% of global net ecosystem production from terrestrial ecosystems (Drake et al., 2018). This is approximately double the oceanic uptake of anthropogenic CO 2, which slows climate change and drives ocean acidification. Our understanding of what drives the export of C into the LOAC, its fate therein, and hence its export to the open ocean, remains incomplete.

PurposeTop‐face control of weld penetration in TIG welding is required for fully automated systems to overcome variations in the welding process and fixturing systems.Design/methodology/approachThis paper presents a system based upon based on the real‐time vision measurement and control of the upper surface or “topface” weld pool size. The primary objective has been to demonstrate the feasibility of using vision‐based image processing to provide measurements and the subsequent control of upper bead weld geometrical properties during the weld formation or molten phase and correlate this to the backface weld bead size.FindingsVision based measurement of the upper surface of the weld pool can be used, in real‐time, to control the weld pool size. This allows more uniform weld penetration to be achieved in the presence of disturbances.Research limitations/implicationsThe system requires that the pool edges can be accurately identified using a correlation method. This requires images with good contrast between the weld pool and the workpiece.Practical implicationsThe system is applicable to both continuous and pulsed TIG welding.Originality/valueA novel reference feature correlation‐based image analysis algorithm has been developed that may be configured to operate with a number of different welding processes. The issues of system integration, i.e. interfacing the system with legacy welding equipment are also discussed.

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Density gradients in coastal regions with significant freshwater input are large and variable and are a major control of nearshore circulation. However their measurement is difficult, especially where the gradients are largest, close to the coast, with significant uncertainties because of a variety of factors -time and spatial (horizontal and vertical) scales are small, tidal currents are strong and water depths shallow. Whilst temperature measurements are relatively straightforward, measurement of salinity (the dominant control of spatial variability for density) can be less reliable in turbid coastal waters. 2The nearshore density gradients in Liverpool Bay are investigated using an integrated multiyear data set from an in situ buoy, instrumented ferry and HF radar. The ferry is particularly useful for estimating coastal density gradients since measurements are made right from the mouth of Mersey, where gradients are on average 3x10 -4 kg m -4 . Using measurements at the single in situ site by the Mersey Bar, 17 km from land, density gradients can be estimated from the tidal excursion or by using ferry data; both giving average values of 5x10 -5 kg m -4 .Nine years of surface salinity measurements there show no evidence of predominant periodicities, although there is a weak annual cycle, and no consistent relation with storms or floods, leading to the conclusion that the majority of the Mersey plume, for most of the time, lies closer to the English shore than the Mersey Bar. Liverpool Bay's circulation is the dominant factor, with wind forcing tending to reinforce it for wind speeds greater than 5 -10 m s -1 . Near bed currents are consistently shoreward and near surface currents northward.

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