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 →
Java-Sumatra Niño/Niña: two long-lost siblings of El Niño
There are many siblings, cousins, and distant relatives of El Niño spanning the Pacific, Atlantic, and Indian Oceans who share a feature in common: ocean surface temperature anomalies along eastern boundaries linked to changes in the upwelling of cooler water from below. So far, climate scientists have identified a total of 14 members of this... 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 →
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 →
ENSO plays little role in early-season Atlantic hurricane activity
This is a guest blog by Robert West. Robert is a postdoctoral research associate in the Northern Gulf Institute (NGI) at the Mississippi State University and is also affiliated with NOAA's Atlantic Oceanographic and Meteorological Laboratory. Differences in sea surface temperature anomalies (SSTAs) between the tropical Atlantic and Pacific oceans are known to influence atmospheric... 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 →
A Seasonal Probabilistic Outlook for Tornadoes (SPOTter) in the Contiguous U.S.
This new study accepted in Monthly Weather Review (Lee et al., 2021) presents an experimental model for Seasonal Probabilistic Outlook for Tornadoes (SPOTter) in the contiguous U.S. for March, April and May, and evaluates its forecast skill. This forecast model uses the leading empirical orthogonal function modes of regional variability in tornadic environmental parameters (i.e.,... Continue Reading →
Why does the Arctic temperature rise faster in the cold season?
The Arctic warming response to increasing greenhouse gas is substantially greater than the rest of the globe. It has been suggested that this phenomenon, commonly referred to as Arctic amplification, and its peak in boreal fall and winter result primarily from the so-called lapse-rate feedback, which is associated with the vertical structure of tropospheric warming,... Continue Reading →
What caused the abrupt reduction of the South Indian Ocean heat & sea level in 2014–2016 and the ensuing quick recovery?
A decade-long increase of the basin-wide sea level and heat content in the subtropical southern Indian Ocean (SIO) during 2004–2013 ended abruptly, immediately following the onset of the strong 2014–2016 El Niño. Interestingly, this unprecedented drop of the SIO heat quickly recovered during the weak 2017–2018 La Niña. A study recently published in Science Advances... Continue Reading →
Co-variability of Pacific‐Atlantic SST contrast, Caribbean Sea tropical rainfall and U.S. summer to fall rainfall variability
In the U.S., peak summer (June-July) rainfall variability, especially east of the Rockies, is largely linked to North Atlantic sea surface temperature (SST) anomalies and associated variations in the Bermuda High. However, these well-established relationships almost completely break down in late summer to mid fall (August-October). Thus, operational seasonal forecast models have generally low skill... Continue Reading →