Recent recovery of the Antarctic Bottom Water and its contribution to the Global Meridional Overturning Circulation

The lower limb of the Global Meridional Overturning Circulation (GMOC) is supplied by  the sinking of the heavy water mass that forms around the Antarctica, known as the Antarctic Bottom Water (AABW).  Repeat hydrographic data along the Atlantic, Pacific and Indian Ocean sections observed during the mid 1990s, 2000s and 2010s indicate that the volume... Continue Reading →

Enhanced carbon sequestration by the North Atlantic Ocean during the Last Glacial Maximum

According to Redfield stoichiometry, marine organisms incorporate and release PO4 and Dissolved Inorganic Carbon (DIC) in a relatively fixed proportion. Additionally, PO4 in the ocean is not affected by air-sea exchange. Therefore, PO4 and DIC in the ocean can be used to estimate biology-driven versus air-sea flux-driven oceanic DIC redistributions. Applying this method to sediment core data, a new paper... Continue Reading →

Extreme U.S. Great Plains heat waves are linked to East Asian Monsoon

Heat waves are the leading weather‐related cause of death in the U.S. For example, the most recent U.S. extreme heat waves that occurred over the Great Plains in 2011 and 2012 caused 362 deaths. These events are unusual and largely unpredictable beyond the synoptic time scale. However, their number and severity have increased and are projected... Continue Reading →

Recent intensification of Amazonian flooding extremes is linked to the tropical Atlantic warming and tropical Pacific cooling

The Amazonian River basin hosts the one of the major global deep tropical convective systems, and thus drives the global Hadley and Walker circulations and the global hydrological cycle. Changes in the water cycle and deep convection activity in this region are, however, largely affected by remote oceans, especially the tropical Pacific, via the Walker circulation.... Continue Reading →

Deep Indo-Pacific Oceans are still in the Little Ice Age

The Little Ice Age (LIA) is a period of cold global average surface temperatures from around 1600 to 1850, following the Medieval Warm Period (950 ~ 1250). A new study published in Science suggested that since the ocean adjusts to the surface thermal anomalies with the time scales of 100 ~ 1,000 years, some parts of the... Continue Reading →

Glacial weakening of the AMOC and the associated increase in deep ocean carbon deposit

During the mid-Pleistocene between 1,250 and 700 kyr ago (ka), Earth’s climate oscillated between warmer interglacial periods and cooler glacial periods with reduced and expanded polar ice sheets, respectively. Paleo records indicate that the Atlantic meridional overturning circulation (AMOC)  was relatively weaker during glacial periods likely due to reduced evaporation and increased freshwater input from glaciers to the... Continue Reading →

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 →

Potential breakup of marine stratocumulus clouds under greenhouse warming may speed up ocean warming

Stratocumulus clouds aloft the eastern subtropical Pacific and Atlantic Oceans cool the ocean by shading it from solar radiation. The stratocumulus cloud droplets absorb and emit longwave radiation very efficiently, while downwelling longwave flux above the cloud tops originates from high altitude and thus cooler atmospheric temperatures (becasue the free troposphere above the stratocumulus clouds is dry and has... 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 →

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