Arctic sea level variability from high-resolution model simulations and implications for the Arctic observing system Ocean Science DOI 10.5194/os-18-51-2022 6 April 2022 This study explores the Arctic sea level variability depending on different timescales and the relation to temperature, salinity and mass changes, identifying key parameters and regions that need to be observed co-ordinately. The decadal sea level variability reflects salinity changes. But it can only reflect salinity change at periods of greater than 1 year, highlighting the requirement for enhancing in situ hydrographic observations and complicated interpolation methods. Read more
Rectified tidal transport in Lofoten–Vesterålen, northern Norway Ocean Science DOI 10.5194/os-17-1753-2021 16 February 2022 Non-linear tidal dynamics can produce prominent time-mean transport in coastal regions where strong tidal currents interact with topography. We investigate tidal-induced transport using a tidally driven ocean model for Lofoten-Vesterålen in northern Norway and find that both tidal pumping and tidal rectification can play an important role for time-mean transport in the region. The study emphasizes the importance of non-linear tidal dynamics for time-mean transport in complex coastal regions. Read more
Dynamics of fortnightly water level variations along a tide-dominated estuary with negligible river discharge Ocean Science DOI 10.5194/os-17-1605-2021 24 January 2022 Understanding tidal hydrodynamics is essential for water resources management in estuarine environments. In this study, we propose an analytical model to examine the fortnightly water level variations due to tidal motions alone in tide-dominated estuaries. Details of the analytical model show that changes in the mean depth or length of semi-arid estuaries affect the fortnightly tide amplitude, which has significant potential impacts on the estuarine ecosystem management. Read more
Interannual variability in contributions of the Equatorial Undercurrent (EUC) to Peruvian upwelling source water Ocean Science DOI 10.5194/os-17-1385-2021 8 December 2021 The Equatorial Undercurrent (EUC) is a key influence on upwelling of nutrient-rich waters associated ecosystems off Peru. To quantify this influence, we backtrack upwelling waters in a computer model of ocean currents, annually, over 1989–2007. The EUC influence varies from year to year, dominating in warm El Niño years, when the EUC extends much closer to the Peruvian coast. In other years, more “local” upwelling is associated with coastal winds, coincident with major key population shifts. EUC) to Peruvian upwelling source water">Read more
Drifting dynamics of the bluebottle (Physalia physalis) Ocean Science DOI 10.5194/os-17-1341-2021 3 December 2021 The bluebottle (Physalia physalis), or Portuguese man o’ war, is well known for the painful stings caused by its tentacles. Its drifting dynamics have not been widely explored, with previous studies using simple assumptions to calculate its drift. Considering similarities with a sailboat, we present a new theoretical model for the drifting speed and course of the bluebottle in different wind and ocean conditions, providing new insights into the parameterization of its complex drifting dynamics. Read more
A dynamically based method for estimating the Atlantic meridional overturning circulation at 26° N from satellite altimetry Ocean Science DOI 10.5194/os-17-1321-2021 24 November 2021 In the North Atlantic, ocean currents carry warm surface waters northward and return cooler deep waters southward. This type of ocean circulation, known as overturning, is important for the Earth’s climate. This overturning has been measured using a mooring array at 26° N in the North Atlantic since 2004. Here we use these mooring data and global satellite data to produce a new method for monitoring the overturning over longer timescales, which could potentially be applied to different latitudes. Read more
Tropical deoxygenation sites revisited to investigate oxygen and nutrient trends Ocean Science DOI 10.5194/os-17-833-2021 13 August 2021 Six tropical areas in the Pacific, Atlantic and Indian oceans were investigated for trends for the years since 1950 for temperature, salinity, oxygen and nutrients at 50 to 300 m and 300 to 700 m depth. Generally, temperature increases, oxygen decreases and nutrients often increase. Overlain variability on the trends seem to be related to climate modes. Different trends indicate that oxygen and nutrient trends cannot by completely explained by local warming. Read more
FES2014 global ocean tide atlas: design and performance Ocean Science DOI 10.5194/os-17-615-2021 7 June 2021 Since the mid-1990s, a series of FES (finite element solution) global ocean tidal atlases has been produced with the primary objective to provide altimetry missions with a tidal de-aliasing correction. We describe the underlying hydrodynamic/data assimilation design and accuracy assessments for the FES2014 release. The FES2014 atlas shows overall improved performance and has consequently been integrated in satellite altimetry and gravimetric data processing and adopted in ITRF standards. Read more
Medusa–Aqua system: simultaneous measurement and evaluation of novel potential halogenated transient tracers HCFCs, HFCs, and PFCs in the ocean Ocean Science DOI 10.5194/os-17-509-2021 21 May 2021 Observations of transient tracer distribution provide essential information on ocean ventilation. The use of several commonly used transient traces is limited as their atmospheric mole fractions do not monotonically change. Here we explore new potential oceanic transient tracers with an analytical system that simultaneously measures a large range of compounds. Combined with the known atmospheric history and seawater solubility, we discuss the utility of selected HCFCs, HFCs, and PFCs as tracers. HCFCs, HFCs, and PFCs in the ocean">Read more
Response of tidal flow regime and sediment transport in North Malé Atoll, Maldives, to coastal modification and sea level rise Ocean Science DOI 10.5194/os-17-319-2021 5 March 2021 Changes to coastlines and bathymetry alter tidal dynamics and associated sediment transport processes, impacting upon a number of threats facing coastal regions, including flood risk and erosion. Especially vulnerable are coral atolls such as those that make up the Maldives archipelago, which has undergone significant land reclamation in recent years and decades and is also particularly exposed to sea level rise. Read more
