According to the recharge-discharge oscillator theory (Jin, 1997), the leading mode of tropical Pacific upper ocean heat content anomalies is a predictor (or a precursor) for the onset of El Niño - Southern Oscillation (ENSO) at the interannual time scale. A new study published in Nature (Zhao et al., 2024) utilized multiple global sea surface... Continue Reading →
Atlantic Niña brewing: An implication for the 2024 hurricane season
Currently (as of June 22, 2024), a phenomenon known as Atlantic Niña is brewing in the tropical Atlantic Ocean. As the Atlantic counterpart of La Niña in the Pacific, Atlantic Niña is characterized by the appearance of cold sea surface temperature anomalies (SSTAs) in the eastern equatorial Atlantic. It is known to reduce rainfall and... Continue Reading →
Quad-State Tornado Outbreaks promoted by a long-lived PNA
On December 10, 2021, one of the most destructive winter tornado outbreaks developed in northeastern Arkansas. This tornado outbreak, later coined as the Quad-State Tornado Outbreaks by the news media, struck portions of the Ohio Valley, including Missouri, Illinois, Tennessee, and Kentucky, from December 10 to 11, 2021. According to the National Oceanic and Atmospheric... Continue Reading →
Climate and weather scientists in the U.S. don’t talk to each other
As a climate scientist, I have worked and interacted with many weather scientists in the past 20 years or so. I am also currently in a task force team to advance subseasonal (2~4 weeks) forecasts of severe weather activity in the U.S. I have learned so much from weather scientists about how longer-term climate processes... Continue Reading →
Why is it hard to identify the subpolar and subtropical jets from zonal-mean zonal wind profiles?
Two important atmospheric jet streams that shape the extratropical zonal wind field in both hemispheres are the subtropical jet and the subpolar jet. The subtropical jet is located around 30° latitude line at the boundary between the Hadley cell and the Ferrel cell, and is predominantly a high-altitude feature. Since it is largely in thermal-wind... Continue Reading →
MJO-driven onset of the 2021 Atlantic Niño
Atlantic Niño is the Atlantic counterpart of El Niño in the Pacific, often referred to as El Niño's little brother. It was previously thought to have only regional influence on rainfall variability in West Africa, but a growing number of studies have shown that Atlantic Niño also plays an important role in the development of... Continue Reading →
El Niño’s little brother in the Atlantic may not be so little when it comes to its impact on hurricanes
Atlantic Niño, characterized by warm sea surface temperature (SST) anomalies in the eastern equatorial Atlantic, is the Atlantic counterpart of the Pacific El Niño. Due to its smaller size in zonal extent, it is often referred to as El Niño’s little brother. It was previously thought to have a limited regional influence on rainfall variability... 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 →
Nearshore sea ice shield Antarctic ice shelves from the damaging impact of ocean waves
The Larsen ice shelves extend along the east coast of the Antarctic Peninsula over the northwest part of the Weddell Sea. From north to south, these segments are called the Larsen A, B, C, and D, bordered by Filchner–Ronne Ice Shelf south of the Weddell Sea. In 1995, the Larsen A ice shelf completely disintegrated,... Continue Reading →
North Atlantic zonal winds will shift northward and become more extreme in the future
The warming response of the upper atmosphere is much stronger in the tropics due to higher water vapor content and frequent deep tropical convection that maintains the atmosphere column well-mixed. As a result, the zonal jet strength, which is largely proportional to the meridional gradient of atmosphere temperature via "thermal wind relationship" is projected to... Continue Reading →
