Journal Highlights

Could Stratospheric Ozone Depletion Make Hadley Cells Expand?

From Eos.org: Research Spotlights—

Convection-driven Hadley cells are expanding poleward. Scientists now may have uncovered part of the reason why.

In 1735, meteorologist George Hadley shook up his field by proposing a novel model of global atmospheric circulation, since named the Hadley cell, in which warm air rises at the equator and heads toward the poles, before cooling and sinking back toward the Earth’s surface at midlatitudes. Over time, especially within the past few decades, these large-scale circulation patterns have been visibly widening, for reasons unknown to scientists. 

The southernmost edges of the Hadley cell in the Southern Hemisphere are defined by the set of points where sea level pressure is highest. Using a technique called optimal fingerprinting analysis, Kim et al. compared a series of model simulations to examine long-term observed changes in these edges during the austral summers (December through February) of 1979–2009. They found that the southernmost edges of the Hadley cell over the Atlantic and Indian oceans have been expanding farther poleward during this period. 

While examining causes of these trends, the researchers detected within the models strong signals of anthropogenic forcing, or human activities such as industry and agriculture, which has ultimately led to increases in greenhouse gases. Specifically, the models showed a link between the expansion of Hadley cells and the depletion of, stratospheric ozone. Ozone depletion can lead to “holes” in the ozone, like the one detected over Antarctica in 1985. This would induce cooler conditions over Antarctica, shifting the lower-latitide circulation system poleward—including Hadley cells. 

This newfound knowledge provides an important link in the chain for scientists seeking to understand the Earth’s evolving climate. The authors note that the correlation they uncovered needs to be fleshed out with causes that pinpoint exactly how ozone depletion leads to Hadley cell expansion, and what the future holds for Hadley cells if ozone does or does not recover.  

-- Sarah Witman, Freelance Writer,

RSS

Recent Highlights Across AGU Publications

Eos.org: Earth & Space Science News

View more Earth and space science news from Eos

Download the App

New Android App Available!

Google Play Store Logo

Download the Geophysical Research Letters app from the Google Play Store

iOS App for iPad or iPhone

GRL IOS App

Download the Geophysical Research Letters app from the Apple store


AGU Career Center


AGU Unlocked


Featured Special Collection

Early Results: Juno at Jupiter 

Early results from Juno's mission at Jupiter including approach to Jupiter and the first perijove pass (PJ1). Juno's scientific objectives include the study of Jupiter's interior, atmosphere and polar magnetosphere with the goal of understanding Jupiter's origin, formation and evolution. This collection of papers provides early results from Juno's measurements of the gravity and magnetic fields, deep atmospheric microwave sounding, infrared, visible and ultraviolet images/spectra and an array of fields and particles instruments as well as context for the early results with respect to current theory and models of Jupiter's formation and evolution. Topics include both Juno - Jupiter related theoretical models and data analysis as well as collaborative observations made from Earth based assets.