A new study by Amaya and co-authors in the Special “Explaining Extremes of 2019 from a Climate Perspective” Issue of BAMS now reveals that the record thin ocean mixed layer depth (MLD) that drove a Blob 2.0 in the northeast Pacific Ocean was exacerbated by a multi-decadal shoaling of the mean MLDs in this region since 1980.
Under global warming, the ITCZ is projected to shift towards the equator, leading to squeeze in the annual-mean tropical ascent and far-reaching impacts on global circulation. Zhou and coauthors researched the observed and projected ITCZ changes based on a variety of observation and reanalysis datasets and ensemble projections of climate models, and found that the observed ITCZ changes are largely opposite to the projected future changes.
Subseasonal to seasonal climate forecasts in the US depends heavily on atmospheric and oceanic conditions in the tropical Indian and Pacific Ocean regions. While ENSO dominates seasonal predictability, the primary source of global predictability on subseasonal timescales is the MJO. To understand how ENSO and MJO interact, the authors isolated both MJO and ENSO signals and found that depending on the simultaneous location of the MJO convection and the background state of ENSO, the two signals can either enhance or mask each other.
To improve atmospheric and oceanographic monitoring, a new type of autonomous marine vehicle, the Saildrone, has been developed and deployed in over 40 cruises from which data are publicly available. Coupled with data from other sources such as satellites, Saildrone measurements could be useful for future algorithm and numerical model improvements, particularly at the fine spatial scale and in complex and previously data-sparse ocean regions.
New research illustrates that the key to recognizing the influence of the Gulf Stream and Kuroshio Extension on the seasonal mean and longer-term climate is through a proper understanding of how the ocean influences atmospheric fronts.
In two papers, Jin and coauthors investigated how decadal variations of subsurface ocean heat content (50–300 m) in the Indian Ocean respond to conditions in the Pacific region.
A coupling in Pacific dynamics has been increasing in observational records between 1950–2017, leading to more frequent occurrences of multi-year warm events like the marine heatwave of 2014–15
Researchers found that atmospheric rivers that impact the West Coast contain more tropical moisture than average, indicating that long-distance transport of tropical moisture does occur.
ENSO experienced a regime shift in the late 1970s, after which events become stronger and less frequent. Researchers now conclude that the regime shift did not occur by chance but was due to a “real” change in the ENSO system.
Research shows that SST may explain a significantly smaller percentage of the variance in tropical cyclone intensification in the Atlantic as compared to the western North Pacific and eastern-central Pacific.
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