Multiple equilibria in a coupled ocean–atmosphere–sea ice general circulation model (GCM) of an aquaplanet with many degrees of freedom are studied. Three different stable states are found for exactly the same set of parameters and external forcings: a cold state in which a polar sea ice cap extends into the midlatitudes; a warm state, which is ice free; and a completely sea ice–covered ‘‘snowb...

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...

The adjoint of an ocean general circulation model is used as a tool for investigating the causes of changes in ENSO SST indices. We identify adjoint Kelvin and Rossby waves in the sensitivities to sea level and wind stress at earlier times, which can be traced back for more than a year through western and weak eastern boundary reeections. Depending on the thermocline depth the rst and second ba...

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...

Antarctic Intermediate Water is formed at the high mid-latitudes of the Southern Ocean. In many ocean general circulation model simulations with coarse resolution and a z-coordinate, a mid-depth salinity minimum characteristic of this intermediate water is reproduced. However, for the real ocean it remains unclear which are the dominant processes in the formation of this water mass and which ar...

The instrumental temperature record is of insufficient length to fully express the natural variability of past temperature. High elevation tree-ring widths from Great Basin bristlecone pine (Pinus longaeva) are a particularly useful proxy to infer temperatures prior to the instrumental record in that the tree-rings are annually dated and extend for millennia. From ring-width measurements integr...

[1] The extratropical sources of equatorial undercurrent (EUC) water have been identified for an ocean circulation model using Lagrangian trajectory analysis, lt has been found that the EUe waters emenate from a wide range of latitudes in the Pacific basin, with its densest constituent watennass being Subantarctic Mode Water (SAMW) from 50S, Further analysis of the basin-scale circulation field...

An ocean general circulation model (OGCM) with wetting and drying (WAD) capabilities removes the vertical-wall coastal assumption and allows simultaneous modeling of open-ocean currents and water run-up (and run-down) across movable land–sea boundaries. This paper implements and tests such a WAD scheme for the Princeton Ocean Model (POM) in its most general three-dimensional setting with strati...