Featured Research

from universities, journals, and other organizations

Tropical upper atmosphere 'fingerprint' of global warming

Date:
May 22, 2013
Source:
University of Hawaii ‑ SOEST
Summary:
The winds of the quasibiennial oscillation in the tropical upper atmosphere have greatly weakened at some altitudes over the last six decades, according to a new study. The finding is consistent with computer model projections of how the upper atmosphere responds to global warming induced by increased greenhouse gas concentrations.

This image shows QBO amplitude near the equator at a height of 11 miles: Observed values from balloon wind measurements from 1950s to present; simulations from a climate model driven with observed concentrations of greenhouse gases from 1900 to 2005 and then with projected increase through 2100.
Credit: Kevin Hamilton

In the tropics at heights more than 10 miles above the surface, the prevailing winds alternate between strong easterlies and strong westerlies roughly every other year. This slow heartbeat in the tropical upper atmosphere, referred to as the quasibiennial oscillation (QBO), impacts the winds and chemical composition of the global atmosphere and even the climate at Earth's surface.

The pulse of the QBO has weakened substantially at some altitudes over the last six decades, according to a new study by scientists at the International Pacific Research Center, University of Hawaii at Manoa, and the Japan Agency for Marine-Earth Science and Technology. The decline in the strength of the QBO is consistent with computer model projections of how the upper atmosphere responds to global warming induced by increased greenhouse gas concentrations. The study appears in the May 23, 2013, online issue of Nature.

"This is the first demonstration of a systematic long-term trend in the observed QBO record," says co-author Kevin Hamilton and Director of the IPRC. "We see a similar trend in computer models of the global atmosphere when they simulate the last century using the historical changes of greenhouse gases. So this change in upper atmospheric behavior can be considered part of the "fingerprint" of the expected global warming signal in the climate system."

The global atmospheric circulation is characterized by air slowly rising in the tropics into the upper atmosphere and sinking at higher latitudes. While this circulation is so slow that a blob of air may take decades to travel to the upper atmosphere, it impacts the chemical composition of the global atmosphere because many chemical properties are very different in the lower and upper atmosphere layers. Although computer models used to project climate changes from increasing greenhouse gas concentrations consistently simulate an increasing upward airflow in the tropics with global warming, this flow cannot be directly observed.

"We demonstrated that the mean upward-air motion suppresses the strength of the QBO winds in the models and thus interpret our observed weakened QBO trend as confirmation that the mean upward velocity in the tropics has indeed been increasing," notes Hamilton.

Hamilton provides an example of why the upward airflow is so significant: "The manufacture of ozone-destroying chemicals such as the freon compounds used in the past in spray cans and in refrigerators has been largely banned for over 20 years. These chemicals, however, remain in the atmosphere for many decades. They are slowly flushed out of the lower atmosphere into the upper atmosphere where they are destroyed. Stronger mean upward airflow transports these chemicals more quickly into the upper atmosphere, and the ozone layer will recover more quickly to its natural state before the introduction of man-made freon compounds."


Story Source:

The above story is based on materials provided by University of Hawaii ‑ SOEST. Note: Materials may be edited for content and length.


Journal Reference:

  1. Yoshio Kawatani, Kevin Hamilton. Weakened stratospheric quasibiennial oscillation driven by increased tropical mean upwelling. Nature, 2013; 497 (7450): 478 DOI: 10.1038/nature12140

Cite This Page:

University of Hawaii ‑ SOEST. "Tropical upper atmosphere 'fingerprint' of global warming." ScienceDaily. ScienceDaily, 22 May 2013. <www.sciencedaily.com/releases/2013/05/130522131158.htm>.
University of Hawaii ‑ SOEST. (2013, May 22). Tropical upper atmosphere 'fingerprint' of global warming. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2013/05/130522131158.htm
University of Hawaii ‑ SOEST. "Tropical upper atmosphere 'fingerprint' of global warming." ScienceDaily. www.sciencedaily.com/releases/2013/05/130522131158.htm (accessed September 1, 2014).

Share This




More Earth & Climate News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Washington Wildlife Center Goes Nuts Over Baby Squirrels

Reuters - US Online Video (Aug. 30, 2014) An animal rescue in Washington state receives an influx of orphaned squirrels, keeping workers busy as they nurse them back to health. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Raw: Volcano Erupts on Papua New Guinea

Raw: Volcano Erupts on Papua New Guinea

AP (Aug. 29, 2014) Several communities were evacuated and some international flights were diverted on Friday after one of the most active volcanos in the region erupts. (Aug. 29) Video provided by AP
Powered by NewsLook.com
Raw: Small Volcanic Eruption in Iceland

Raw: Small Volcanic Eruption in Iceland

AP (Aug. 29, 2014) Icelandic authorities briefly raised the aviation warning code to red on Friday during a small eruption at the Holuhraun lava field in the Bardabunga volcano system. (Aug. 29) Video provided by AP
Powered by NewsLook.com
As Drought Continues LA "water Police" Fight Waste

As Drought Continues LA "water Police" Fight Waste

AFP (Aug. 29, 2014) In the midst of a historic drought, Los Angeles is increasing efforts to go after people who waste water. Five water conservation "cops" drive around the city every day educating homeowners about the drought. Duration: 02:17 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins