Active Pacific meridional overturning circulation (PMOC) during the warm Pliocene

An essential element of modern ocean circulation and climate is the Atlantic meridional overturning circulation (AMOC), which includes deep-water formation in the subarctic North Atlantic. However, a comparable overturning circulation is absent in the Pacific, the world’s largest ocean, where relatively fresh surface waters inhibit North Pacific deep convection. We present complementary measurement and modeling... Continue Reading →

Multidecadal weakening of Indian summer monsoon circulation induces an increasing northern Indian Ocean sea level

North Indian Ocean sea level has shown significant increase during last three to four decades. Analyses of long-term climate data sets and ocean model sensitivity experiments identify a mechanism for multidecadal sea level variability relative to global mean. Our results indicate that North Indian Ocean sea level rise is accompanied by a weakening summer monsoon... Continue Reading →

Meridional Overturning Circulation (MOC) in Europa?

This article appeared in Nature Geoscience in 2014 used a numerical model to hypothesize that a meridional overturning circulation (MOC) exists in the ocean beneath the icy surface of Jupiter's moon Europa. The geothermal heat generated from tidal flexing drives Europa's MOC, which carries heat toward the surface in the low latitudes then poleward. This study... Continue Reading →

The central role of ocean dynamics in connecting the North Atlantic Oscillation to the extratropical component of the Atlantic Multidecadal Oscillation

The relationship between the North Atlantic Oscillation (NAO) and Atlantic sea surface temperature (SST) variability is investigated using models and observations. Coupled climate models are used in which the ocean component is either a fully dynamic ocean or a slab ocean with no resolved ocean heat transport. On time scales less than 10 yr, NAO... Continue Reading →

Arctic sea-ice decline weakens the Atlantic Meridional Overturning Circulation

The ongoing decline of Arctic sea ice exposes the ocean to anomalous surface heat and freshwater fluxes, resulting in positive buoyancy anomalies that can affect ocean circulation. In this study, we use an optimal flux perturbation framework and comprehensive climate model simulations to estimate the sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to such... Continue Reading →

The North Atlantic Oscillation as a driver of rapid climate change in the Northern Hemisphere

Pronounced climate changes have occurred since the 1970s, including rapid loss of Arctic sea ice, large-scale warming and increased tropical storm activity in the Atlantic. Anthropogenic radiative forcing is likely to have played a major role in these changes, but the relative influence of anthropogenic forcing and natural variability is not well established. The above... Continue Reading →

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