RESUMEN
Changes in ocean heat content (OHC), salinity, and stratification provide critical indicators for changes in Earth's energy and water cycles. These cycles have been profoundly altered due to the emission of greenhouse gasses and other anthropogenic substances by human activities, driving pervasive changes in Earth's climate system. In 2022, the world's oceans, as given by OHC, were again the hottest in the historical record and exceeded the previous 2021 record maximum. According to IAP/CAS data, the 0-2000 m OHC in 2022 exceeded that of 2021 by 10.9 ± 8.3 ZJ (1 Zetta Joules = 1021 Joules); and according to NCEI/NOAA data, by 9.1 ± 8.7 ZJ. Among seven regions, four basins (the North Pacific, North Atlantic, the Mediterranean Sea, and southern oceans) recorded their highest OHC since the 1950s. The salinity-contrast index, a quantification of the "salty gets saltier-fresh gets fresher" pattern, also reached its highest level on record in 2022, implying continued amplification of the global hydrological cycle. Regional OHC and salinity changes in 2022 were dominated by a strong La Niña event. Global upper-ocean stratification continued its increasing trend and was among the top seven in 2022.
RESUMEN
The increased concentration of greenhouse gases in the atmosphere from human activities traps heat within the climate system and increases ocean heat content (OHC). Here, we provide the first analysis of recent OHC changes through 2021 from two international groups. The world ocean, in 2021, was the hottest ever recorded by humans, and the 2021 annual OHC value is even higher than last year's record value by 14 ± 11 ZJ (1 zetta J = 1021 J) using the IAP/CAS dataset and by 16 ± 10 ZJ using NCEI/NOAA dataset. The long-term ocean warming is larger in the Atlantic and Southern Oceans than in other regions and is mainly attributed, via climate model simulations, to an increase in anthropogenic greenhouse gas concentrations. The year-to-year variation of OHC is primarily tied to the El Niño-Southern Oscillation (ENSO). In the seven maritime domains of the Indian, Tropical Atlantic, North Atlantic, Northwest Pacific, North Pacific, Southern oceans, and the Mediterranean Sea, robust warming is observed but with distinct inter-annual to decadal variability. Four out of seven domains showed record-high heat content in 2021. The anomalous global and regional ocean warming established in this study should be incorporated into climate risk assessments, adaptation, and mitigation.
RESUMEN
The Gulf Stream is the upper-ocean limb of a powerful current system known as the Atlantic Meridional Overturning Circulation-the strongest oceanic pacemaker of the Atlantic Ocean and perhaps the entire Earth's climate. Understanding the long-term variability of the Gulf Stream path is critical for resolving how the ocean, as a climate driver, works. A captivating facet of the Gulf Stream as a large-scale ocean climate phenomenon is its astounding resilience on timescales of decades and longer. Although the Gulf Stream has been vigorously explored over many decades, its long-term constancy deserves further scrutiny using the increased volume of in situ marine observations. We report a new study where the decadal variability of the Gulf Stream north wall (defined by the 15 °C isotherm at 200 m)-the major marker of the Gulf Stream pathway-is analyzed using in situ observations collected over the last 53 years.
RESUMEN
In this study, we examined possible impacts of the Yangtze River Three Gorges Dam (TGD), the world largest hydroelectric construction, on the adjacent marine ecosystem of the East China Sea (ECS) during its initial water storage period. The TGD filled the first one-third of its storage capacity of 39 billion m3 in 10 days in June 2003, causing an abrupt reduction in the river flow into the ECS. Noticeable changes in the microbial community structure including pico-sized autotrophs, heterotrophic bacteria and microbial diversity in the estuary and the ECS were observed 2 months later. Although causes for these changes could be multiple, the sudden decrease of river runoff and an ensuing intrusion of ECS ocean currents were postulated to be among the major ones.
