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 →
Why climate models are unable to reproduce the observed Antarctic sea-ice expansion
Antarctic sea-ice has expanded over the period of continuous satellite monitoring, which seemingly contradicts ongoing global warming resulting from increasing concentrations of greenhouse gases. A variety of hypotheses have been proposed to explain the observed Antarctic sea-ice expansion and corresponding model–observation discrepancy, but the issue remains unresolved. In a new study published in Nature Climate... 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 →
Future El Niño events will develop faster and persist longer
Previous studies based on the climate models participating in the Coupled Model Intercomparison Project (CMIP) have suggested an increase in the frequency of extreme El Niño events in the 21st Century in response to increasing greenhouse gases. Several studies have attributed these shifts in El Niño frequency and amplitude to the projected changes in the... Continue Reading →
New aircraft-based observations confirm the role of the Southern Ocean as a significant carbon sink
Ship-based CO2 flux estimates of the contemporary air-sea flux of CO2 showed that the Southern Ocean (south of 35oS) plays an important role as a significant carbon sink, with a net uptake at the rate of −0.8 ~ −1.0 Pg C/year (Takahashi et al., 2009; Landschützer et al., 2014) largely consistent with climate model-based estimates... Continue Reading →
Increasing river alkalinity slows ocean acidification in river-dominated ocean margins
Although ocean acidification (OA) is mainly driven by the ocean uptake of anthropogenic carbon dioxide from the atmosphere, multiple factors including changes in ocean temperature, biological processes, and river discharge influence its temporal progression. In a new paper accepted in the Geophysical Research Letters, a team of researchers from the Northern Gulf Institute of the... Continue Reading →