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 →

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 largest freshwater reservoir in the Arctic Ocean  (Proshutinsky et al., 2009) and also is a region of the largest summer sea... Continue Reading →

Pantropical inter-ocean interactions & the rising influence of tropical Atlantic Ocean

Conventional view so far has been that El Nino - Southern Oscillation (ENSO) is largely responsible for energizing the dominant modes of SST variability  in the tropical Atlantic and Indian Oceans through changes in the Walker circulation and extratropical atmospheric waves. However, recent studies have shown that SST variability in the tropical Atlantic and Indian... Continue Reading →

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