A major impediment to understanding long-term changes in the marine nitrogen (N) cycle is the persistent uncertainty about the rates, distribution, and sensitivity of its largest fluxes in the modern ocean. We use a global ocean circulation model to obtain the first 3-D estimate of marine denitrification rates that is maximally consistent with available observations of nitrate deficits and the ...

The role of the Indonesian Throughflow (ITF) in the thermocline circulation of the low-latitude Pacific Ocean is explored using a high-resolution primitive equation ocean circulation model. Seasonally forced runs for a domain with an open Indonesian passage are compared with seasonally forced runs for a closed Pacific domain. Three cases are considered: one with no throughflow, one with 10 Sv o...

An important issue for the interpretation of data from deep-sea cores is the time for tracers to be transported from the sea surface to the deep ocean. Global ocean circulation models can help shed light on the timescales over which a tracer comes to equilibrium in different regions of the ocean. In this note, we discuss how the most slowly decaying eigenmode of a model can be used to obtain a ...

The Great Australian Bight south of Australia is an important link for the flow of surface, intermediate and deep water between the Indian and Pacific Ocean. Carbon-14 is a tracer of this flow and for the first time, water samples for subsequent carbon-14 analysis were collected at several locations within the Bight. We report and discuss the observed carbon-14 distribution in relation to the g...

A global ocean circulation model is formulated in terms of the “residual mean” and used to study eddy–mean flow interaction. Adjoint techniques are used to compute the three-dimensional eddy stress field that minimizes the departure of the coarse-resolution model from climatological observations of temperature. The resulting 3D maps of eddy stress and residual-mean circulation yield a wealth of...

The present study deals with the implementation of an eddy resolving model of the Levantine and Aegean basins and its one-way nesting with a coarse resolution (1/8× 1/8) global Mediterranean general circulation model. The modelling effort is done within the framework of the Mediterranean Forecasting System Pilot Project as an initiative towards real-time forecasting within the eastern Mediterra...

This paper presents the application of the Discrete Linear Quadratic Control (DLQC) method for a parameter optimization problem in a marine ecosystem model. The ecosystem model simulates the distribution of nitrogen, phytoplankton, zooplankton and detritus in a water column with temperature and turbulent diffusivity profiles taken from a three-dimensional ocean circulation model. We present the...

Flocculation has an important impact on particle trapping in estuarine turbidity maximum (ETM) through associated increases in particle settling velocity. To quantify the importance of the flocculation processes, a size-resolved flocculation model is implemented into an ocean circulation model to simulate fine-grained particle trapping in an ETM. The model resolves the particle size from robust...

Drifting seaweeds plays a major role in areas where they are present. We describe a computer model, Jeosim that clarifies the roles of those seaweeds in relation to their transport using particle tracking algorithm. The Euler rule with trapezoidal approximation, used to calculate drifting paths, is implemented in JeoSim in discrete events fashion in order to simulate the path and movement of se...

A three dimensional ocean circulation model (Princeton Ocean Model) is utilised to study the thermohaline variability of the eastern Arabian Sea associated with changes in the three input bathymetry data sets, viz. ETOPO5 (E5), Modified ETOPO5 (ME5) and ME5 further modified based on actual fine resolution data collected using Multibeam echo-sounder (MEN5). The temperature and salinity measureme...