13Previous studies have suggested that an eastward propagation of the warm pool

Previous studies demonstrate that recent global warming hiatuses are associated with an ongoing cooling in the eastern Pacific. However, the possible driver for this cooling remains vigorously debated. Present theories can be generally categorized into three different frameworks, the most prevailing theory considering the increased heat uptake in ocean interior as a direct trigger in cooling the eastern equatorial Pacific, the next regarding the prolonged solar minimum as a potential driver in producing weak radiative forcing over the Pacific, while another suggesting that changes in atmospheric water vapour and aerosols play an unnegligible role in absorbing and reflecting solar radiation. Most recently, some studies argue that the ongoing cooling in the eastern Pacific is induced by a strengthening of the easterly trade winds. Nevertheless, observational records coming from the monitoring buoys deployed along the equator by NOAA since 1992 indicate that an intensification of the trade winds is only confined to the central tropical Pacific (around 170° E–170° W) during hiatus decades, elsewhere along the equatorial Pacific the trade winds exhibit a stable condition even a slight weakening in the eastern equatorial Pacific, rendering it as a trigger of this cooling in the eastern Pacific unlikely. Here we use a model and long-term observational data to demonstrate that a persistent cooling in the eastern Pacific is directly linked to an eastward displacement of the Southeast Pacific Subtropical Anticyclone (SPSA). Interactions between the Andes and an eastward shift of the SPSA generate greater pressure gradients in the eastern flank, in turn, stronger alongshore winds and more intense upwelling, ultimately contributing to hiatus decades.

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The liquefaction of nickel ore is widely considered to account for the capsizing and sinking of bulk carriers, but the mechanisms that lead to the incidents still remain uncertain. In this paper, the sloshing motion of fluid with high viscosity in a rectangular tank has been studied; the Level Set Method has been employed to predict the behaviours of fluid sloshing motion under the circumstances of beam seas. In a bid to evaluate the consistency of the numerical solution, a full validation has been performed. The results obtained from the simulations are in good agreement with that from the experiment. The conclusions have also been made that the collapse of the shear resistance of the fluid or increasing heeling moment acquired from the fluid sloshing after liquefaction of the nickel ore may be responsible for the capsizing and sinking of the ships. Hopefully, our conclusions can help ship owners better understand how to take precautions to prevent the ships from capsizing while carrying nickel ore or similar cargos; the results could provide the IMO with the theoretical basis for stipulating new international safe standards for bulk carriers; the numerical methodology can also help engineers to predict sloshing motion of viscous fluids. K E Y WO R D S1. Nickel ore.2. Liquefaction. 3. Sloshing. 4. Stability.

Previous studies suggested that a weakened Gulf Stream may have contributed to the Younger Dryas (YD) cold event, however the physical mechanism of the Gulf Stream weakening is unclear. Here, we utilize paired Mg/Ca and δ18O measurements of planktonic foraminifera from the northerly and southerly marine sediments in the middle Atlantic Ocean to reconstruct past changes in tropical surface ocean temperature and salinity over the past 14 ka. We demonstrate that during the YD the sea surface temperature (SST) at the northerly core (0°16′S) was up to 2.1–2.7°C cooler whereas the SST at the southerly core (14°53′S) was up to 0.8–1.6°C warmer than modern temperatures. The δ18O, salinity values, accumulation rates, and other hydrological elements at the northerly core all exhibit opposite patterns with those at the southerly core. The antiphased variations of the paleohydrological elements at the northerly and southerly cores suggest that the Atlantic Equatorial Currents shifted southward significantly from its present‐day position during the YD, possibly resulting in a decrease of the Gulf Stream, in turn a cool Northern Hemisphere.