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 →
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 →
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 →
Ocean precursors to the extreme Atlantic 2017 hurricane season
A recent study published in nature communications investigated three ocean precursors, namely surface latent heat flux and wind stress curl over the main development region (MDR, 10–20°N, 20–80°W) and the Atlantic Meridional Overturning Circulation (AMOC) at 26.5°N, to the active hurricane seasons in 2005, 2010 and 2017. The study showed that in 2005 and 2010, a weakened... Continue Reading →
May 24, 2018 – NOAA’s Climate Prediction Center predict a near- or above-normal 2018 Atlantic hurricane season
NOAA’s forecasters predict a 70-percent likelihood of 10 to 16 named storms (winds of 39 mph or higher), of which 5 to 9 could become hurricanes (winds of 74 mph or higher), including 1 to 4 major hurricanes (category 3, 4 or 5; with winds of 111 mph or higher). An average hurricane season produces 12 named storms,... Continue Reading →
Hurricane Harvey links to ocean heat content and climate change adaptation
While hurricanes occur naturally, human‐caused climate change is supercharging them and exacerbating the risk of major damage. Here, using ocean and atmosphere observations, we demonstrate links between increased upper ocean heat content due to global warming with the extreme rainfalls from recent hurricanes. Hurricane Harvey provides an excellent case study as it was isolated in... Continue Reading →
Ocean dynamics plays a key role in driving the Atlantic Multidecadal Oscillation (AMO)
The recently proposed atmosphere-forced thermodynamics mechanism of the AMO challenged the well-known ocean dynamics mechanism, and thus it is important to identify a key feature associated with the AMO that can be used to distinguish between the two mechanisms. In this study, the spatial structure of AMO is analyzed and compared between the observations and... Continue Reading →
Is AMOC slowing down?
A recent article appeared in Nature suggested that the AMOC has been very weak during the past 150 years since the end of the Little Ice Age (LIA) , and that enhanced freshwater fluxes from the Arctic and Nordic seas towards the end of the LIA weakened Labrador Sea convection and thus the AMOC. They... Continue Reading →