Recent  

Water exchange through the Åland Sea, Baltic Sea, affects the conditions in the neighbouring Gulf of Bothnia. Pathways and variability of flows were studied with a high-resolution hydrodynamic model. Our analysis showed a northward transport in the deep layer and net transport towards south in the surface layer. While on the southern edge of the Åland Sea the primary route of deep water exchange is through Lågskär Deep, still some deep water bypasses it to the Åland Sea.

The surface ocean is turbulent from several hundreds km to a few km. More the current field is turbulent more waves that are traveling over the underlying current are scattered. In the present works we focus on an isolated eddy where spontaneous instabilities have been occurred resulting in emergence of smaller structures. Thanks to the wave scattering we have been able to retrieve the underlying surface current gradients normally not retrievable with traditional current measurements.

Satellite measurements of sea surface salinity (SSS) are compared with measurements in the ocean to verify the quality of the satellite data. SSS satellites measure average values over a footprint with size ~100 km, whereas ocean values are usually taken at a single point in space and time. Using SSS data from a network of buoys across the global tropics we estimate the size of the mismatch between satellite and in place measurements to better understand the error structure of the satellite.

Significant trends of sea-ice in Hudson Bay have led to a considerable increase in shipping activity. Therefore, understanding sea level variability is an urgent issue crucial for safe navigation and coastal infrastructure. Using the sea level, atmospheric and river discharge data, we assess environmental factors impacting variability of sea-level at Churchill. We find that it is dominated by wind forcing, with the seasonal cycle generated by the seasonal cycle in atmospheric circulation.

Observations of sea level, taken manually by reading a tide pole, were carefully taken at a number of locations around Ireland in 1842 as part of the first land survey of Ireland. Our study investigates how useful this type of sea level observation is for understanding mean sea level and tidal change. We find that, when carefully adjusted for seasonal, meteorological, and astronomical factors, these data can provide important insights into changing sea levels.

Ocean heat and carbon content increase proportionately as the planet warms. However, circulation changes in response to changing heat content, redistributing preindustrial heat, carbon and salinity fields. Redistribution leaves properties unchanged, and so we may leverage our skill identifying preindustrial carbon in order to trace preindustrial heat and salinity field redistribution. Excess salinity opposes excess temperature induced density change, and redistribution grows continually.

Marine heatwave refers to discrete, prolonged warm ocean condition known to cause severe destruction in marine ecosystems. We find that coastal waters off the west coast of India have experienced a rapid 15-fold increase in heatwave days since the early 80s'. This resulted in more frequent and longer marine heatwave events in the last decade. we show that the rapid warming in the Arabian Sea in the last decade is the primary cause of the observed enhanced heatwave events in this basin.

The Ioffe-2000 transect presented a “screenshot” of volume suspended particulate matter distribution in the northern part of the Equatorial Atlantic against the background of hydrographic data. Alongside the general agreement with the three-layer model of the ocean SPM distribution, there was a massive area with high SPM concentrations above the Sierra-Leone Rise and local SPM maxima in the bottom layer within Antarctic Bottom Water.

From our analysis, we find that air-sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation in the Iceland Basin. However, the spatial distribution of the SPMW transformation is most sensitive to surface density changes, which set the surface area for the source waters, as opposed to the direct influence of the air-sea fluxes. Hence, we highlight the importance of understanding what forces the variability of the surface density field.

In this work we used a concept named Geochemical Fingerprinting, using isotopes of Neodymium and Lead as a tool to recognize the main sources and the phisical processes responsible for the transport and deposition of sediments on a large area of the South Atlantic margin. Distinct sources, such as Antarctica, the Andean Cordillera, the Río de la Plata basin, and the old rocks from the Brazilian shield are identified.

In this study, long-term tide gauge observations and multi-mission satellite altimetry data were used to investigate the spatial distribution of the long-period tidal contribution in Chinese seas and analyze the relative long-period tidal contribution rate into four regions. The result indicate that the long-period tidal constituent cannot be neglected in the establishment of the LNLW datum to improve tidal datum precision.

Nonlinear tidal dynamics can produce prominent time-mean transports in coastal regions where strong tidal currents interact with topography. We investigate tidal induced transports 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 transports in the region. The study emphasizes the importance of nonlinear tidal dynamics for time-mean transports in complex coastal regions.

We investigated how surface mixed layer (vertically homogeneous layer at the sea surface due to winter cooling) develops stratification between late winter and early spring. We used autonomous observing platforms to take time series data under sever weather conditions and found that lateral transports of lighter water were more important than surface heating during the observation period. We also found that the lateral process was also promote biological activities near the sea surface.

We use data crossing Herald Canyon in the Chukchi Sea collected in 2008 and 2014 together with numerical modeling to investigate the circulation in the western Chukchi Sea. A large fraction of water from the Chukchi Sea enters the East Siberian Sea south of Wrangel Island and circulates in an anticyclonic direction around the island. To assess the differences between years, we use numerical modelling results, which show that high frequency variability dominates the flow in Herald Canyon.

We propose a simple probabilistic method for highlighting fronts in the Southern Ocean with model data from below the mixed layer. We compare it with an image processing method that provides a more localised view of fronts that effectively highlights currents. We suggest that our new probabilistic method has multiple advantages, including not being reliant on surface data.

The Bluebottle (Physalis Physalis), called the Portuguese Man of War in the Atlantic, is well known for the painful stings caused by their tentacles. The drifting dynamics of this species has not been widely explored, with previous studies using simple assumptions to calculate the Bluebottle's drift. This study presents a new theoretical model for the drifting speed and course of the Bluebottle in different wind and ocean conditions.

The Atlantic Meridional Overturning Circulation (AMOC) quantifies the impact of the ocean on climate and climate change. Here we show that a high-resolution ocean model is able to realistically simulate ocean currents. While the mean representation of the AMOC depends on choices made for the model and on the atmospheric forcing, the temporal variability is quite robust. Comparing the ocean model with ocean observations, we able to identify that the AMOC has declined over the past two decades.

Oxygen poor regions in the open ocean restrict marine habitats. Global climate simulations show large uncertainties regarding the prediction of these areas. We analyze the representation of the simulated oxygen minimum zones in the Arabian Sea using ten climate models. We give an overview of the main deficiencies that cause the model-data misfit in oxygen concentrations. This detailed process analysis shall foster future model improvements regarding the oxygen minimum zone in the Arabian Sea.

We demonstrate that even sparse BGC Argo profiles can substantially improve biogeochemical prediction via a priori model tuning. By assimilating satellite surface chlorophyll and physical observations, subsurface distributions of physical properties and nutrients were improved immediately. The improvement of subsurface chlorophyll was modest initially but was greatly enhanced after adjusting the parameterization for light attenuation through further a priori tuning.

Correct surface ocean circulation forecasts are highly relevant for search and rescue, oil-spill and ecological processes understanding, among others. High Frequency Radars (HFR) is a remote sensing technology that measure surface currents in coastal areas with high temporal and spatial resolution. We performed a series of experiments in which we use HFR observations from the Ibiza Channel to improve the forecasts provided by a Regional ocean model in the Western Mediterranean.