The flow which constitutes the conveyor belt in the Hamburg large-scale geostrophic ocean general circulation model has been investigated with the help of a particle tracking method. In the region of North Atlantic Deep Water formation a thousand trajectories were calculated backward in time to the point where they upwell from the deep ocean. Both the three-dimensional velocity field and convec...

In one of the most complex Earth science inverse modeling initiatives, the Estimation of the Circulation and Climate of the Ocean (ECCO) project is developing greatly improved estimates of the three-dimensional, time-evolving state of the global oceans [1, 2]. To this end, the project is applying extimation/optimal control techniques to constrain a state-of-the-art parallel general circulation ...

[1] We explore the potential predictability of rapid changes in the Atlantic meridional overturning circulation (MOC) using a coupled global climate model (HadCM3). Rapid changes in the temperature and salinity of surface water in the Nordic Seas, and the flow of dense water through Denmark Strait, are found to be precursors to rapid changes in the model’s MOC, with a lead time of around 10 yea...

The present paper examines ways in which the seasonal cycle influences the evolution of El Niño in the tropical Pacific. The following hypotheses and associated physical mechanisms are investigated: (i) Hypothesis 1 (H1)—the seasonal warming of the cold tongue early in the calendar year (January–April) favors the initial growth of an event; (ii) hypothesis 2 (H2)—during an event, the warm surfa...

(I) Ocean State Estimation [1, 2] I Given: – a set of (possibly different types of) observations – a numerical model & set of initial / boundary conditions I Question: (estimation / optimal control problem) Find optimal trajectory consistent with observations within prior error I Approach: Minimize least square function J (~u) measuring model vs. data misfit −→ seek ~ ∇uJ (~u) to infer update ∆...

An assessment on the scientific impact of random errors in wind direction (< 45°) retrieved from space-based observations under weak wind (< 7 m/s) conditions was made. Half of the winds over global oceans are below 7 m/s, in their long-term averages, and these weak winds cover most of the tropical, subtropical , and coastal oceans. Introduction of these errors in the semi-daily winds causes, o...

An ocean general circulation model of the tropical Atlantic Ocean is used to study the vertically integrated vorticity equation for the annual mean flow in the Atlantic North Equatorial Countercurrent (NECC). It is found that the nonlinear terms play an important role in the vorticity budget, in the western part of the basin. Sverdrup balance does not hold in the region of the North Brazil Curr...

Between ;750 and 635 million years ago, during the Neoproterozoic era, the earth experienced at least two significant, possibly global, glaciations, termed ‘‘Snowball Earth.’’ While many studies have focused on the dynamics and the role of the atmosphere and ice flow over the ocean in these events, only a few have investigated the related associated ocean circulation, and no study has examined ...

[1] Although the world ocean is known to be a major sink of anthropogenic carbon dioxide, the exact processes governing the magnitude and regional distribution of carbon uptake remain poorly understood. Here we show that Southern Hemisphere winds, by altering the Ekman volume transport out of the Southern Ocean, strongly control the regional distribution of anthropogenic uptake in an ocean gene...