Tor Gammelsrød

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• Cand. real.
• Professor Emeritus at University of Bergen

Estuaries are the main gateway of nutrients into marine coastal waters. Human activities and biodegradation processes in coastal freshwater and mangrove swamps are the major sources of nutrients. The present study examines the sources, sinks, and flux rates of nitrogen (N), phosphorus (P), and silicon (Si) through the interfaces river-estuary, mang...

The residual circulation in estuaries determines the net exchange of water, heat, salt, fine sediments and drifting biological organisms between estuarine and nearshore marine waters. The Bons Sinais Estuary in central Mozambique is ~ 30 km long with the city of Quelimane and an industrial port on the northern bank of its upper reaches. To investig...

Xai-Xai Beach is a shallow semi-enclosed lagoon, about 2,000m long, 200m wide and 3m average depth, protected from ocean swell by a reef about 0.75m above the Mean Sea Level, with small gaps along its extension. Despite being protected from ocean waves, the lagoon, which is popular with tourists, is a dangerous place to swim, with an average of 8-9...

The South Equatorial Current (SEC) in the Indian Ocean bifurcates when it reaches Madagascar leading, respectively, to the North East Madagascar Current (NEMC), which contours the island flowing northwestward, and to the South East Madagascar Current (SEMC), which flows southwestward. Both branches eventually contribute to the greater Agulhas Curre...

Three years (2008–2011) of current measurements outside Pemba (∼13°S), Mozambique, are presented. Oil and gas reserves are found in the region, and knowledge of the ocean current climate is important for safe offshore operations. The full-depth current profile at Pemba was estimated by comparing with moorings further south. The moored record was al...

This report summarizes the 2013 field experiment at Tofo Beach, Tofo, Inhambane, in which measurements of bottom topography, currents, sea level, and surface waves were collected. A visual assessment of the surrounding areas was also made, and some comments are made concerning the morphology at Tofo Beach. Keywords: Nearshore dynamics, beach morph...

Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 km×0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the cur...

In September 2009, the R.V. Dr. Fridtjof Nansen surveyed the western coast of Madagascar. Environmental parameters of temperature, salinity, fluorescence and oxygen were profiled with a CTD probe and continuously underway at 5 m utilising a thermosalinograph equipped with a fluorescence sensor. A ship mounted Acoustic Doppler Current Profiler (ADCP...

Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 kmÂ0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the cur...

The artisanal catch contributed about 87% of the overall annual marine fish production in Mozambique, estimated to 115,000 -140,000 tons, as per fish statistics of the period 2000 and 2004. The availability of most of the coastal marine fisheries depends on a number of factors among which the freshwater input into the coastal waters, either though...

Interactions between the Southern Ocean and the Weddell Sea ice shelves are important both to the Antarctic Ice Sheet and to the production of globally significant water masses. Here we review the interaction between the Filchner-Ronne Ice Shelf and the shelf sea in which it floats. The continental shelf processes leading to the production of Wedde...

Properties of the dense ice shelf water plume emerging from the Filchner Depression in the southwestern Weddell Sea are described, using available current meter records and CTD stations. A mean hydrography, based on more than 300 CTD stations gathered over 25 yr points to a cold, relatively thin and vertically well-defined plume east of the two rid...

The strait between Novaya Zemlya and Frans Josef Land, here called the Barents Sea Exit (BSX) is investigated using data obtained from a current-meter array deployed in 1991–1992, and two numerical models (ROMS and NAME). Combining the observations and models the net volume flux towards the Arctic Ocean was estimated to 2.0 ± 0.6 Sv (1 Sv = 106 m3s...

This article was submitted without an abstract, please refer to the full-text PDF file.

This article was submitted without an abstract, please refer to the full-text PDF file.

Properties of the dense ice shelf water plume emerging from the Filchner Depression in the southwestern Weddell Sea are described, using available current meter records and CTD stations. A mean hydrography, based on more than 300 CTD stations gathered over 25 yr points to a cold, relatively thin and vertically well-defined plume east of the two rid...

From 1993 to 1996, three oceanographic moorings were deployed in the north-western Barents Sea, each with a current meter and an upward-looking sonar for measuring ice drafts. These yielded three years of currents and two years of ice draft measurements. An interannual variability of almost I m was measured in the average ice draft. Causes for this...

From 1993 to 1996, three oceanographic moorings were deployed in the north-western Barents Sea, each with a current meter and an upward-looking sonar for measuring ice drafts. These yielded three years of currents and two years of ice draft measurements. An interannual variability of almost I m was measured in the average ice draft. Causes for this...

Cold shelf waters flowing out of the Filchner Depression in the southern Weddell Sea make a significant contribution to the production of Weddell Sea Bottom Water (WSBW), a precursor to Antarctic Bottom Water (AABW). We use all available current meter records from the region to calculate the flux of cold water (<- 1.9°C) over the sill at the northe...

1] The Fram Strait sea ice velocity was measured by means of a new method using moored Doppler Current Meters in the period 1996 – 2000. Almost 3 years of ice velocity observations near 79°N 5°W are analyzed. The average southward ice velocity was 0.16 m/s. The correlation between the ice velocity and the cross-strait sea level pressure (SLP) diffe...

1] In this study we report results from satellite-linked conductivity-temperature-depth (CTD) loggers that were deployed on wild, free-ranging white whales to study the oceanographic structure of an Arctic fjord, Storfjorden, Svalbard. The whales dove to the bottom of the fjord routinely during the study and occupied areas with up to 90% ice-cover,...

Temperature trends, of various length, observed during the twentieth century are com- pared with a number of estimates of natural climate variability. These estimates are obtained from palaeoclimate reconstructions (some based solely on tree-ring density, others utilise multiple proxy types) and from a 1400-year unforced (control) simula- tion usin...

We present the first year-long current meter records ever obtained near the floating Filchner-Ronne Ice Shelf in the Weddell Sea. The currents are steered along the ice front, but in the lower layer where the bottom topography is descending toward the west the current has a component toward the ice front of about 3 cm s-1. During winter the tempera...

Over the past decade, the multiyear oceanographic time series from ocean weather station Mike at 66°N, 2°E indicate a warming by about 0.01°C yr1 in the deep water of the Norwegian Sea. The time of onset of this warming is depth dependent, starting at 2000-m depth in 1987 but not at the 1200-m level until 1990. The warming abruptly halts around 199...

The upper ocean temperatures in the Angolan-Namibian coastal waters were anomalously high during March 1995, with positive temperature anomalies of up to 8°C. Maximum temperature differences were 30-50 m deep, reflecting a deepening of the thermocline from normal depths of 10-30 m. The unusually warm water mass covered the Angolan coast from Cabind...

Variations in the catch of shallow water shrimp at the Sofala Bank, central Mozambique, are considered using abundance indices of Penaeus indicus by length groups. Both monthly, seasonal and year to year fluctuations are presented and related to Zambezi River runoff and rainfall. The influence of varying fishing effort is also investigated. Correla...

Year-to-year variations of shrimp abundance in the ocean adjacent to the Zambezi River mouth are found to be strongly correlated with the wet season runoff. Since the river is regulated by the Cahora Bassa Dam, the author argues that it is possible to tune the runoff to match the life cycle of the shrimp such that the fishing potential is enhanced....

Oxygen 18 and helium isotope data from stations located in the Filchner Depression, on the continental slope of the southern Weddell Sea, and in the central Weddell Sea are presented and discussed. The 18O and 4He signals imprinted on the water circulating under the Filchner/Ronne Ice Shelf (Ice Shelf Water, or ISW) due to melting of glacial ice at...

The Southern Ocean circulation and sea-ice distribution is briefly described. The formation of extremely cold bottom water in the Weddell Sea and its relation to the floating Ronne-Filchner Ice Shelves is discussed. It is shown that a concentrated swift eroding bottom current with anomalous low ratio transports the cold and dense ice Shelf Water fr...

Hydrographic and current measurements obtained during the Norwegian Antarctic Research Expedition 1978/79 to the southern Weddell Sea are presented. Cold, dense Ice Shelf Water circulating under the floating ice shelves is observed to leave the shelf as a concentrated bottom flow. From moored current metres this discharge is estimated at 0.7 106 m3...

Hydrographic (CTD) observations obtained with R/V‘Lance’in July-August 1982 across the Fram Strait are presented. The extent and the presence of traditional water masses such as Atlantic Water, Polar Water and Greenland Sea Deep Water are discussed. The complicated hydrographical structure in the upper water masses due to eddies and fronts near the...

Hydrographic (CTD), current and water level measurements obtained in the vicinity of the floating Ronne and Filchner Ice Shelves are presented. The distribution of Western Shelf Water (S > 34.7) and Ice Shelf Water (T<−1.9°C) are discussed. The general circulation in the area seems to consist of two large cyclonic gyres, one in the Filchner Depress...

CTD observations from the southern Weddell Sea in 1977 show that Ice Shelf Water originating under the floating Filchner Ice Shelf overflows at the sill of the Filchner Depression and can be identified on the continental slope at more than 2000m depth. Intrusions of Weddell Deep Water upon the shelf are especially noticeable in the region of dense...

Hydrographic (CTD), current and water level measurements obtained in the vicinity of the floating Ronne and Filchner Ice Shelves are presented. The distribution of Western Shelf Water (S > 34.7) and Ice Shelf Water (T<-1.9"C) are discussed. The general circulation in the area seems to consist of two large cyclonic gyres, one in the Filchner Depress...

CTD observations from the southern Weddell Sea in 1977 show that Ice Shelf Water originating under the floating Filchner Ice Shelf overtlows at the sill of the Filchner Depression and can be identified on the continental slope at more than 2000m depth. Intrusions of Weddell Deep Water upon the shelf are especially noticeable in the region of dense...

Hydrographic (CTD) observations obtained with R/V ‘Lance’ in July-August 1982 across the Fram Strait are presented. The extent and the presence of traditional water masses such as Atlantic Water, Polar Water and Greenland Sea Deep Water are discussed. The complicated hydrographical structure in the upper water masses due to eddies and fronts near t...

Hydrographic and current measurements obtained during the Norwegian Antarctic Research Expedition 1978/79 to the southern Weddell Sea are presented. Cold, dense Ice Shelf Water circulating under the floating ice shelves is observed to leave the shelf as a concentrated bottom flow. From moored current metres this discharge is estimated at 0.7. lo6 m...

The hydrographic (CTD) observations and pendulum current measurements obtained with M/S ‘Lance’ in August 1981 in the area west and north of Spitsbergen, are presented. The warm and saline northward flow, known as the West Spitsbergen Current, is found to follow the shelf break. In the Fram Strait the hydrographic structure is complicated because o...

we have obtained one year of measurements from a subsurface instrumented mooring carrying two current meters and one bottom pressure recorder in the strait between Nordaustlandet and Kvitøya in the northeastern Svalbard archipelago. The observations show a mixed tide with typical amplitudes 0.4 db and 10cm sec−1. The semidiurnal tide is characteriz...

We have obtained one year of measurements from a subsurface instrumented mooring carrying two current meters and one bottom pressure recorder in the strait between Nordaustlandet and Kvitøya in the northeastern Svalbard archipelago. The observations show a mixed tide with typical amplitudes 0.4 db and 1Ocm sec-I. The semidiurnal tide is characteriz...

The hydrographic (CTD) observations and pendulum current measurements obtained with M/S 'Lance' in August 1981 in the area west and north of Spitsbergen, are presented. The warm and saline northward flow, known as the West Spitsbergen Current, is found to follow the shelf break. In the Fram Strait the hydrographic structure is complicated because o...

During the Norwegian Antarctic Research Expedition 1978–79, direct measurements of oscillations were carried out on 15 icebergs using a tiltmeter with an accuracy of ± 10 μrad. The amplitude of the oscillations varied from zero to about 10 ³ μrad. The zero amplitude indicates that the berg was grounded and this was confirmed by echo-sounding from t...

During the Norwegian Antarctic Research Expedition 1978–79, two experiments were carried out to measure flow around icebergs. Drogues were equipped with surface markers constructed to drift with the flow at various levels down to 260 m. They were tracked by a helicopter and a Motorola positioning system. As expected, the surface-layer (0 to 20 m) f...

During the Norwegian Antarctic Research Expedition 1978–79, temperature measurements of a number of icebergs and the surrounding surface water were made, using an airborne precision radiation thermometer. All icebergs were embedded in cold water-masses with temperatures generally below 0°C and thus the observed temperature anomalies were relatively...

Observations taken on an expedition into the Arctic Ocean north of Spitsbergen indicated the existence of a region of wind-driven upwelling along the edge of the ice pack. Models underestimate the 12-kilometer width of the upwelling region.

A simple calculation shows that plane Couette flow in a rotating invsicid neutrally buoyant fluid is unstable to roll perturbations. The linear shear flow may exist in nature as a boundary layer flow or a thermal wind. The results of the calculations are compared with observations of wind streaks on the ocean and cloud streets in the atmosphere.

Measuring the magnitude and variability of the ice and freshwater flux through Fram Strait is an important element in understanding climate variability in the Arctic. Since the major part of the ice and freshwater that leaves the Arctic passes through Fram Strait, this passage can be considered a key area for estimating the net ice production in th...

The Benguela region off the coast of south-west Africa experiences a climatic perturbation similar to the El Niño phenomenon in the Pacific Ocean. This Benguela Niño seems to occur about once per decade. It is characterised by higher sur-face temperature, lower surface salinity and increased sea level. It was last observed in 1995. Here we describe...

Overview Many features of glacial–interglacial cycles are not well explained by insolation changes alone, in particular, the causes and role of at-mospheric CO 2 variations. We suggest that, in a glacial world, the bottom ocean should be highly saline due to brine formation over the Antarctic continental shelf associated with sea-ice formation. Thi...