Featured Research

from universities, journals, and other organizations

Forest fire smoke in the stratosphere: New insights into pyrocumulonimbus clouds

Date:
August 30, 2010
Source:
Naval Research Laboratory
Summary:
Meteorologists are now discovering that changes in the frequency of occurrence and intensity of wildfires has substantial consequences for a variety of important problems including atmospheric changes. Superimposed on this important topic is a relatively new discovery: forest fire smoke in the stratosphere, an area of the atmosphere that begins nearly 38 thousand feet above the Earth's surface. As a result, a poorly understood aspect of wildfire behavior -- pyrocumulonimbus firestorm dynamics and atmospheric impact -- is becoming the focus of increasing attention.

Smoke from wildfire blocks out the sun at Yellowstone National Park -- Terrace Spring (1988).
Credit: US National Park Service

Wildfires can wreak widespread havoc and devastation, affecting environmental assets lives, property and livelihoods. Meteorologist Mike Fromm of the Naval Research Laboratory, in collaboration with several national and international laboratories, is now discovering that changes in the frequency of occurrence and intensity of wildfires has substantial consequences for a variety of important problems including atmospheric change.

Related Articles


Superimposed on this important topic is a relatively new discovery, forest fire smoke in the stratosphere, an area of the atmosphere that begins nearly 38 thousand feet above the Earth's surface.

As a result, a poorly understood aspect of wildfire behavior -- pyrocumulonimbus firestorm dynamics and atmospheric impact -- is becoming the focus of increasing attention. Pyrocumulonimbus (pyroCb) is a fire-started or augmented thunderstorm that in its most extreme manifestation injects huge abundances of smoke and other biomass burning emissions into the lower stratosphere. The reason is a particularly energetic form of 'blowup' caused by pyroCbs. Although known to form naturally and through anthropogenesis, attention to this topic has heightened with growing concern regarding anthropogenic climate forcing and the apparent increase of fires in the wildland/urban interface.

Global and regional warming trends have long been identified and associated with exacerbated wildfire occurrence but extreme injection by thunderstorms was previously judged to be unlikely because the tropopause, a transitional zone from the troposphere to the stratosphere, is considered to be a strong barrier to convection. This view is reflected in many instances in which mystery clouds in the stratosphere were attributed to volcanic eruptions, although volcanic evidence was lacking.

"Direct attribution of mysterious stratospheric aerosols has only occurred in the last decade," said Fromm. "While pyroconvection and pyrocumulus are well known, the peculiar vertical extent of the impact potential of pyrocumulonimbus escaped our attention."

That is, until it was discovered that pyroCbs from Canada wildfires had injected smoke (and other related emissions) well beyond the tropopause and into the stratospheric "overworld."

In 2002, survey of the Canada/USA fire season identified 17 pyroCb occurrences associated with newsworthy fires such as the Hayman, Rodeo/Chediski, and Biscuit fires. Data from these fires indicated pyroCbs injected smoke into the lowermost stratosphere offering a plausible alternate explanation for phenomena that were previously assumed to involve volcanic aerosols.

As such, two recurring themes have developed as pyroCb research unfolds. First, some "mystery layer" events -- puzzling stratospheric aerosol-layer observations -- and other layers reported as volcanic aerosol, can now be explained in terms of pyroconvection. Secondly, pyroCb events have been found to occur surprisingly frequently and are likely a relevant phenomenon of many wildfires.

"These findings will lead to a re-analysis of climatologies related to volcanic effects on the stratosphere and a 'new' climatology and geography of pyroCb occurrence worldwide," added Fromm.

Reports of pyroCb are increasing in science literature but are still rare. However, the hemispheric spread of smoke and other biomass burning emissions in the stratosphere due to pyroCbs will now be looked at as an impact having important climate consequences, likely resulting in improved models on air quality, thermo-chemical effects of smoke pollution and global pollution transport.


Story Source:

The above story is based on materials provided by Naval Research Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Naval Research Laboratory. "Forest fire smoke in the stratosphere: New insights into pyrocumulonimbus clouds." ScienceDaily. ScienceDaily, 30 August 2010. <www.sciencedaily.com/releases/2010/08/100826122612.htm>.
Naval Research Laboratory. (2010, August 30). Forest fire smoke in the stratosphere: New insights into pyrocumulonimbus clouds. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2010/08/100826122612.htm
Naval Research Laboratory. "Forest fire smoke in the stratosphere: New insights into pyrocumulonimbus clouds." ScienceDaily. www.sciencedaily.com/releases/2010/08/100826122612.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava Inches Closer to Highway

Raw: Lava Inches Closer to Highway

AP (Dec. 21, 2014) Officials have opened a new road on Hawaii's Big Island for drivers to take care of their daily needs if encroaching lava from Kilauea Volcano crosses a highway and cuts them off from the rest of the island. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Raw: Scuba Diving Santa Off Florida Keys

Raw: Scuba Diving Santa Off Florida Keys

AP (Dec. 20, 2014) A scuba diving Santa Claus explored the waters of the Florida Keys National Marine Sanctuary. Dive shop owner Spencer Slate makes the dive each year to help raise money for charity. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Obama: Better Ways to Create Jobs Than Keystone Pipeline

Obama: Better Ways to Create Jobs Than Keystone Pipeline

AFP (Dec. 19, 2014) US President Barack Obama says that construction of the Keystone pipeline would have 'very little impact' on US gas prices and believes there are 'more direct ways' to create construction jobs. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Lava on Track to Hit Hawaii Market

Raw: Lava on Track to Hit Hawaii Market

AP (Dec. 19, 2014) Lava from an active volcano on Hawaii's Big Island slowed slightly but stayed on track to hit a shopping center in the small town of Pahoa. (Dec. 19) Video provided by AP
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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