Atlantic deep water is now warm enough to melt previously stable Greenland glacier

Ice sheet melting from Greenland's glaciers accounts for an increasing proportion of global sea level rise, losing ~330 billion tonnes of ice per year during 2006-2018 (compared to ~120 billion tonnes of ice per year during 1901-1990). A new study published in Nature Communications examined recent changes at K.I.V Steenstrups Nordre Bræ (66.53°N, 34.57°W), a... Continue Reading →

The Global Ocean Conveyor Belt is Reshaping from the Southern Ocean

As the surface ocean warms and polar ice sheets melt due to increasing anthropogenic greenhouse gases in the atmosphere, near-surface stratification is increasing almost everywhere, including the major deep water formation regions in the high-latitude North Atlantic and around Antarctica. As a result, the global Meridional Overturning Circulation (MOC), also known as the global ocean... Continue Reading →

Antarctic Bottom Water (AABW) export pathways across the Southern Ocean

The Antarctic Bottom Water (AABW) is the densest water mass of the global ocean that covers about 30 ~ 40% of the global ocean volume with temperatures ranging from -0.8 to 2°C and salinities from 34.6 to 34.7 psu. It forms around Antarctica and spreads into the Southern Ocean and then into the Atlantic, Indian,... Continue Reading →

Nearshore sea ice shield Antarctic ice shelves from the damaging impact of ocean waves

The Larsen ice shelves extend along the east coast of the Antarctic Peninsula over the northwest part of the Weddell Sea. From north to south, these segments are called the Larsen A, B, C, and D, bordered by Filchner–Ronne Ice Shelf south of the Weddell Sea. In 1995, the Larsen A ice shelf completely disintegrated,... Continue Reading →

North Atlantic zonal winds will shift northward and become more extreme in the future

The warming response of the upper atmosphere is much stronger in the tropics due to higher water vapor content and frequent deep tropical convection that maintains the atmosphere column well-mixed. As a result, the zonal jet strength, which is largely proportional to the meridional gradient of atmosphere temperature via "thermal wind relationship" is projected to... Continue Reading →

An overlooked role of the subtropical gyre circulation in regulating the AMOC

It is a common practice in Physical Oceanography to separate the Atlantic Ocean circulations into the meridional overturning and wind-driven gyre components with an assumption that the two components are largely independent of each other. An article published in Nature Communications suggests that the two components are not at all independent. The study shows that... Continue Reading →

Sea-ice retreat may invigorate the weakening Atlantic Meridional Overturning Circulation

Due to rapidly rising air temperature over the Arctic and subarctic regions, the ocean-to-air turbulent (i.e., sensible and latent) heat flux over the Greenland, Iceland, and Norwegian Seas (GINS) has diminished (i.e., less cooling of the surface ocean) steadily during the satellite period (i.e., since the 1970s). This may lead to a reduction of deep... Continue Reading →

Arctic Ocean is experiencing dramatic weight loss due to increasing freshwater storage

The freshwater cycle in the Earth System is a delicate balance between the net loss (i.e., evaporation > precipitation) in the warm tropical-subtropical oceans, the net gain (i.e., precipitation > evaporation) in the cold polar oceans, and the net poleward transport by the atmosphere. These processes maintain the tropical-subtropical oceans salty and the polar oceans... Continue Reading →

Thermohaline Meridional Overturning Circulation on Enceladus

Enceladus is a miniature-size Saturn's moon (Earth's moon is about 7 times larger) known to have a deep ocean (~ 40km) beneath the thick icy crust (~20km). It has been suggested that Enceladus’s interior ocean is heated from below through hydrothermal activity, powered by tidal dissipation. The ocean should in turn carry the heat to... Continue Reading →

Increasing influence of warm and salty Atlantic water on the cold season Arctic sea ice melting

The Arctic Ocean in the upper 100 - 200 m is typically characterized by a cold and fresh surface mixed layer and a layer of rapidly increasing salinity with depth, as known as halocline, separating the surface mixed layer from the warm and salty Atlantic water at depth. Due to large vertical density gradient and... Continue Reading →

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