Post by Andrei Tchentchik on Mar 4, 2020 15:51:25 GMT 2
(.#A.063).- Australia, some of the smoke from fires has reached the stratosphere.
Australia: part of the smoke associated with the fires has reached the stratosphere!
By: Damien Altendorf, scientific writer
January 9, 2020, 1 h 24 min
Pyrocumulonimbus captured in New South Wales on January 4, 2020.
Credits: Michael Thompson.
The smoke from the fires that devastated part of Australia is gradually spreading all around the southern hemisphere. A significant fraction even reached the stratosphere, a layer where the high stability allows them to stay up to several months. If the climatic consequences of these stratospheric injections are still uncertain, they testify to the virulence of the episode that hit the continent.
This weekend and early in the week, a disturbance seeped into southern Australia, bringing in a significantly refreshed air mass and some thunderstorm rain. Blissful conditions which allowed a notable reduction of the fires. However, the fact remains clear: the damage caused by the fires is already enormous.
Credits: Aaron Coleman / Kayne Davis / 9News.
One example among others is presented above. This is a comparison of Kangaroo Island before and after the flames passed. More than a third of the island has been wiped out.
Summary :
Particle injections into the stratosphere
Effects still uncertain
Low layer transport to South America
Particle injections into the stratosphere
In addition to the terrible effects identified on the surface, more exotic influences are also observed. Satellite measurements show, for example, that part of the smoke has infiltrated into the stratosphere. The particles spread over nearly 6,000 kilometers on January 6, 2020, and at an altitude close to 20 kilometers.
Satellite observation of atmospheric aerosol content near New Zealand on January 30, 2019. The white line indicates the tropopause.
Credits: @david_P_Moore.
A phenomenon to be linked to the very convective nature of incendiary plumes. Indeed, many cumulus or cumulonimbus flammagenitus were associated with them. Caught in these virulent thunderstorms, the particles were propelled at high altitude and locally pierced the tropopause. A bit like what happens during strong volcanic eruptions.
Satellite observation of atmospheric aerosol content in the southeast Pacific on January 6, 2020.
Credits: @david_P_Moore.
As the stratosphere is a very stable and non-precipitating atmospheric layer, the residence time of impurities is of the order of several months. Also, they have time to form a very thin hemispherical veil capable of lasting interaction with solar radiation, ozone chemistry, etc. For these reasons, any injection of particles into the stratosphere is carefully monitored.
Effects still uncertain
However, it is still too early to have a precise idea of the consequences that the current episode could have on the climate.
"For volcanoes, the released [sulfur dioxide] reacts with water in the stratosphere and creates sulfate aerosols that can persist for weeks, months, sometimes years (Pinatubo)" explains David Moore, scientist at National Center for Earth Observation. "Sulfate aerosols reflect sunlight and have a cooling effect on the climate that can last for a few years."
Pyrocumulonimbus captured in New South Wales on January 4, 2020. Credits: Michael Thompson.
In the case of an injection with a pyrocumulonimbus, it is not a question of sulfur but aerosols rich in carbon. However, the role played by these latter is poorly understood and it is not trivial to know whether the net effect on the climate system is cooling or warming. Thus, we will have to wait for further work to examine the question. The current event is an ideal opportunity to carry out an in-depth study.
In any case, it is obvious that the quantity of aerosols having passed through the tropopause is not trivial. Even for a situation at pyrocumulonimbus. One observation among many that confirms the virulence of the episode that has been played in recent weeks.
Low layer transport to South America
Note that closer to the ground, large plumes of smoke have also been transported thousands of kilometers towards South America. Satellite animations unequivocally showing the arrival of impurities from the Pacific. In fact, the impacts on visibility were much more direct. As a result, Chile and Argentina were able to observe particularly glowing sunrises and sunsets. However, given the instability that characterizes the troposphere, the residence time of these fumes is limited.
Satellite view of Australian smoke flying over South America on January 8, 2020.
Credits: rammb.cira.colostate.edu/.
Finally, let's not forget the role of gases released into the atmosphere by fires. Greenhouse gases such as CO2 or CH4 (methane), but also pollutants. In particular, carbon monoxide (CO) which reached South America at the same time as the smoke on January 5.
F I N .
Australia: part of the smoke associated with the fires has reached the stratosphere!
By: Damien Altendorf, scientific writer
January 9, 2020, 1 h 24 min
Pyrocumulonimbus captured in New South Wales on January 4, 2020.
Credits: Michael Thompson.
The smoke from the fires that devastated part of Australia is gradually spreading all around the southern hemisphere. A significant fraction even reached the stratosphere, a layer where the high stability allows them to stay up to several months. If the climatic consequences of these stratospheric injections are still uncertain, they testify to the virulence of the episode that hit the continent.
This weekend and early in the week, a disturbance seeped into southern Australia, bringing in a significantly refreshed air mass and some thunderstorm rain. Blissful conditions which allowed a notable reduction of the fires. However, the fact remains clear: the damage caused by the fires is already enormous.
Credits: Aaron Coleman / Kayne Davis / 9News.
One example among others is presented above. This is a comparison of Kangaroo Island before and after the flames passed. More than a third of the island has been wiped out.
Summary :
Particle injections into the stratosphere
Effects still uncertain
Low layer transport to South America
Particle injections into the stratosphere
In addition to the terrible effects identified on the surface, more exotic influences are also observed. Satellite measurements show, for example, that part of the smoke has infiltrated into the stratosphere. The particles spread over nearly 6,000 kilometers on January 6, 2020, and at an altitude close to 20 kilometers.
Satellite observation of atmospheric aerosol content near New Zealand on January 30, 2019. The white line indicates the tropopause.
Credits: @david_P_Moore.
A phenomenon to be linked to the very convective nature of incendiary plumes. Indeed, many cumulus or cumulonimbus flammagenitus were associated with them. Caught in these virulent thunderstorms, the particles were propelled at high altitude and locally pierced the tropopause. A bit like what happens during strong volcanic eruptions.
Satellite observation of atmospheric aerosol content in the southeast Pacific on January 6, 2020.
Credits: @david_P_Moore.
As the stratosphere is a very stable and non-precipitating atmospheric layer, the residence time of impurities is of the order of several months. Also, they have time to form a very thin hemispherical veil capable of lasting interaction with solar radiation, ozone chemistry, etc. For these reasons, any injection of particles into the stratosphere is carefully monitored.
Effects still uncertain
However, it is still too early to have a precise idea of the consequences that the current episode could have on the climate.
"For volcanoes, the released [sulfur dioxide] reacts with water in the stratosphere and creates sulfate aerosols that can persist for weeks, months, sometimes years (Pinatubo)" explains David Moore, scientist at National Center for Earth Observation. "Sulfate aerosols reflect sunlight and have a cooling effect on the climate that can last for a few years."
Pyrocumulonimbus captured in New South Wales on January 4, 2020. Credits: Michael Thompson.
In the case of an injection with a pyrocumulonimbus, it is not a question of sulfur but aerosols rich in carbon. However, the role played by these latter is poorly understood and it is not trivial to know whether the net effect on the climate system is cooling or warming. Thus, we will have to wait for further work to examine the question. The current event is an ideal opportunity to carry out an in-depth study.
In any case, it is obvious that the quantity of aerosols having passed through the tropopause is not trivial. Even for a situation at pyrocumulonimbus. One observation among many that confirms the virulence of the episode that has been played in recent weeks.
Low layer transport to South America
Note that closer to the ground, large plumes of smoke have also been transported thousands of kilometers towards South America. Satellite animations unequivocally showing the arrival of impurities from the Pacific. In fact, the impacts on visibility were much more direct. As a result, Chile and Argentina were able to observe particularly glowing sunrises and sunsets. However, given the instability that characterizes the troposphere, the residence time of these fumes is limited.
Satellite view of Australian smoke flying over South America on January 8, 2020.
Credits: rammb.cira.colostate.edu/.
Finally, let's not forget the role of gases released into the atmosphere by fires. Greenhouse gases such as CO2 or CH4 (methane), but also pollutants. In particular, carbon monoxide (CO) which reached South America at the same time as the smoke on January 5.
F I N .