Tropical explosive volcanic eruptions can trigger El Niño by cooling tropical Africa

Stratospheric aerosols from large tropical explosive volcanic eruptions backscatter shortwave radiation and reduce the global mean surface temperature. Observations suggest that they also favour an El Niño within 2 years following the eruption. Modelling studies have, however, so far reached no consensus on either the sign or physical mechanism of El Niño response to volcanism.... 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 →

Decade-long deep-ocean warming detected in the subtropical South Pacific

The persistent energy imbalance at the top of the atmosphere, inferred from satellite measurements, indicates that the Earth's climate system continues to accumulate excess heat. As only sparse and irregular measurements of ocean heat below 2000 m depth exist, one of the most challenging questions in global climate change studies is whether the excess heat has... 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 influence of environmental variability on the biogeography of coccolithophores and diatoms in the Great Calcite Belt

The Great Calcite Belt (GCB), a region of high calcite concentration from coccolithophores, covers 60 % of the Southern Ocean area. We examined the influence of temperature, macronutrients, and carbonate chemistry on the distribution of mineralizing phytoplankton in the GCB. Coccolithophores occupy a niche in the Southern Ocean after the diatom spring bloom depletes silicic acid.... Continue Reading →

The role of Atlantic overturning circulation in the recent decline of Atlantic major hurricane frequency

Observed Atlantic major hurricane frequency has exhibited pronounced multidecadal variability since the 1940s. However, the cause of this variability is debated. Using observations and a coupled earth system model (GFDL-ESM2G), here we show that the decline of the Atlantic major hurricane frequency during 2005–2015 is associated with a weakening of the Atlantic Meridional Overturning Circulation... Continue Reading →

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

The carbon content of the water masses of the Southern Ocean south of Tasmania has increased over the period 1995–2011, leading to a general decrease in pH. An enhancement in the upwelling of DIC-rich deep waters is the main plausible cause of the increase in carbon in surface waters south of the Polar Front. North... Continue Reading →

Wind-driven ocean dynamics impact on the contrasting sea-ice trends around West Antarctic

Since late 1978, Antarctic sea-ice extent has overall expanded in all seasons in stark contrast to the retreating Arctic sea-ice extent. However, while the sea-ice extent around East Antarctica has increased monotonically, the sea-ice around West Antarctica exhibits regionally and seasonally inhomogeneous trends. For instance, Antarctic sea-ice extent in the East Pacific has decreased substantially... Continue Reading →

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