Ocean storage of anthropogenic CO2 from 1994 to 2007

A paper published in Science estimated the oceanic sink of the anthropogenic CO2 (Cant) over the period of 1994 to 2007 by comparing observations collected from global repeated hydrography cruises between 2003 and 2007 to those from the World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS) program during the 1980s and early 1990s. The... Continue Reading →

Emergence of a shallow aragonite-undersaturated layer in the Southern Ocean

As the ocean absorbs anthropogenic CO2, its pH and carbonate ion concentration  decrease, thereby decreasing the ratio of the concentration of dissolved carbonate ions in the sea water to the concentration of dissolved ions in a saturated solution of aragonite (i.e., aragonite saturation state ΩAr). If ΩAr falls below the threshold ΩAr=1, ocean acidification makes it harder... Continue Reading →

Why does the upper atmosphere cool with increasing carbon dioxide?

According to model simulations with increasing carbon dioxide in the atmosphere, the zonal mean temperature in the atmosphere get warmer in the troposphere (< 10km or > 100hPa) and colder in the stratosphere (10 ~ 50km or 100 ~ 1hPa). A simple explanation is that the amount of infrared heat radiated out to the space... Continue Reading →

Ocean-ice momentum flux reversal and the associated stabilization of the Beaufort Gyre and freshwater accumulation

Driven by the Beaufort High and associated wind-stress curl, the anticyclonic ocean gyre over the Canada Basin, as known as the Beaufort Gyre, is a dominant feature of the Arctic Ocean circulation. The Beaufort Gyre is the the largest freshwater reservoir in the Arctic Ocean  (Proshutinsky et al., 2009) and also is a region of the largest summer... Continue Reading →

Global meridional overturning circulation revisited

Ocean tracers such as heat, salt and carbon are perpetually carried by the global meridional overturning circulation (GMOC) and redistributed between hemispheres and across ocean basins from their source regions. The GMOC is therefore a crucial component of the global heat, salt and carbon balances. In a new article accepted in Geophysical Research Letter, a... Continue Reading →

Natural variability in the Southern Ocean as a driver of the observed Antarctic sea-ice expansion trends

A team of scientists from Princeton University, NOAA-GFDL, and UCAR performed global climate model simulations, using a newly developed coupled ocean–atmosphere model SPEAR (Seamless System for Prediction and Earth System Research). When this model was driven with changes in past radiative forcing, the model simulation did not reproduce the observed increasing trends in sea-ice concentration around... Continue Reading →

Antarctic meltwater slows down global warming by more than a decade

A new study published in Nature used climate models to explore the effects of meltwater from the Antarctic ice sheets and ice shelves on global surface temperature under a warming climate. The study found that the increasing meltwater decreases the surface salinity of the Southern Ocean and thus increases the near-surface stratification, which in turn... Continue Reading →

Deep convection that feeds the AMOC may occur in Arctic Sea under a warming climate

The Atlantic Meridional Overturning Circulation (AMOC) is a key ocean circulation system that carries heat, salt, carbon and other biogeochemical elements along its paths, redistributing them between hemispheres and across ocean basins, and thus is a crucial component of the global heat, salt and carbon balances. At present, the subduction of dense water (i.e., deep convection) that... Continue Reading →

Antarctic Ice Sheet retreat in the Amundsen Sea driven by central tropical Pacific SST variability

A new study appeared in Nature Geoscience (Jenkins et al., 2018) analyzed ocean temperature, salinity, dissolved-oxygen and current measurements from 2000 to 2016 near the Dotson Ice Shelf in the Amundsen Sea to determine temporal changes in net basal melting. The study showed that a decadal cycle dominates the ocean record, which is highly correlates with... Continue Reading →

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