Atlantic Multidecadal Oscillation (AMO) modulates North Atlantic atmospheric blocking

Atmospheric blocking over the high-latitude North Atlantic blocks the westerly jet stream, causing the eastward propagation of weather systems to stall for 7 days or so. An earlier study  by Häkkinen et al. (2011) used the 20th century atmospheric reanalysis product of NOAA (20CR) to show that the wintertime blocking frequency over high latitude North Atlantic covaries... Continue Reading →

North Atlantic Tropical Cyclones have become increasingly likely to “stall” near the coast

Hurricane Dorian was a powerful storm that reached a maximum sustained wind of 185 mph (Cat 5 ≥ 157 mph) during its landfall over Abaco Islands on September 1, 2019. Hurricane Dorian made landfall on Grand Bahama with about the same intensity and stalled just north of the island for 24 hours, causing massive damages... Continue Reading →

Four types of the Madden-Julian Oscillation

Madden-Julian Oscillation (MJO) is the main mode of intraseasonal atmospheric variability in the tropical Indo-Pacific Oceans and the major source of subseasonal predictability of precipitation and extreme weather events in many parts of the globe. Although MJO is known as an eastward propagating equatorial atmospheric kelvin wave, not all MJO events are identical in terms of their strength... Continue Reading →

New multivariate metrics help better monitor and predict global coral breaching events

Key factors that affect regional coral bleaching have been well studied and documented. These include extreme warm temperatures, the duration of extreme cold temperatures, and temperature bimodality (i.e., the exposure of corals to two distinct temperature regimes). However, some of these factors are more important than others in different regions because there are complex and interactive responses to... Continue Reading →

Recent warming of the tropical Indian Ocean may sustain the AMOC from slowing down

A recent study published in Nature Climate Change used a series of coupled ocean-atmosphere model simulations to demonstrate that the tropical Indian Ocean (TIO) warming reduces rainfall over the tropical Atlantic by strengthening the Walker circulation (i.e., increased ascending motion over TIO and increased subsidence over tropical Atlantic). This increases salinity of the upper tropical Atlantic Ocean.... Continue Reading →

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 →

North Atlantic Ocean gyre circulation dictates the interannual sea level variability along the U.S. Southeast and Gulf Coasts

Interannual and longer time-scale sea level changes are relatively small amplitude. However,  they can provide background conditions favorable for the occurrence of extreme sea levels that represent a threat for coastal communities, especially in low-lying and flood-vulnerable regions. A new study accepted in Geophysical Research Letters identified the dominant mode of the ocean gyre-scale sea surface height... 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 →

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