Showing posts with label hydroxyl. Show all posts
Showing posts with label hydroxyl. Show all posts

Friday, December 4, 2015

Ocean Heat Depth

Ocean heat at the equator


On November 24, 2015, equatorial waters at ≈100 m (328 ft) depth at 110-135°W were over 6°C (10.8°F) warmer than average in 1981-2000, as illustrated by above image. The animation below shows equatorial ocean heat over the past few months, illustrating that temperature anomalies greater than 6°C (10.8°F) occurred throughout this period at depths greater than 100 m (328 ft).

The danger of ocean heat destablizing clathrates in the Arctic

The danger is that ever warmer water will reach the seafloor of the Arctic Ocean and destabilize methane that is held there in sediments the form of free gas and hydrates.

So, how comparable is the situation at the equator with the situation in the Arctic? How much heating of the Arctic Ocean has taken place over the past few years?

The image on the right, produced with NOAA data, shows mean coastal sea surface temperatures of over 10°C (50°F) in some areas in the Arctic on August 22, 2007.

In shallow waters, heat can more easily reach the bottom of the sea. In 2007, strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, according to this study, and bottom water temperatures on the mid-shelf increased by more than 3°C (5.4°F) compared to the long-term mean.

This study finds that drastic sea ice shrinkage causes increase in storm activities and deepening of the wind-wave-mixing layer down to depth ~50 m (164 ft) that enhance methane release from the water column to the atmosphere. Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

The image below, replotted by Leonid Yurganov from a study by Chepurin et al, shows sea water temperature at different depths in the Barents Sea, as described in an earlier post.


The image below is from a study published in Nature on November 24, 2013, showing water temperatures measurements taken in the Laptev Sea from 1999-2012.

Water temperatures in Laptev Sea. Red triangles: summer. Blue triangles: winter. Green squares: historic data.
From Shakhova et al., (2013) doi:10.1038/ngeo2007
Before drawing conclusions, let's examine some peculiarities of the Arctic Ocean more closely, specifically some special conditions in the Arctic that could lead to greater warming than elsewhere and feedbacks that could accelerate warming even more.

Amount of methane ready for release

Sediments underneath the Arctic Ocean hold vast amounts of methane. Just one part of the Arctic Ocean alone, the East Siberian Arctic Shelf (ESAS, rectangle on map below, from the methane page), holds up to 1700 Gt of methane. A sudden release of just 3% of this amount could add over 50 Gt of methane to the atmosphere, and experts consider such an amount to be ready for release at any time (see above image).



Total methane burden in the atmosphere now is 5 Gt. The 3 Gt that has been added since the 1750s accounts for almost half of the (net) total global warming caused by people. The amount of carbon stored in hydrates globally was in 1992 estimated to be 10,000 Gt (USGS), while a more recent estimate gives a figure of 63,400 Gt (Klauda & Sandler, 2005). The ESAS alone holds up to 1700 Gt of methane in the form of methane hydrates and free gas contained in sediments, of which 50 Gt is ready for abrupt release at any time.



Imagine what kind of devastation an extra 50 Gt of methane could cause. Imagine the warming that will take place if the methane in the atmosphere was suddenly multiplied by 11.

Whiteman et al. recently calculated that such an event would cause $60 trillion in damage. By comparison, the size of the world economy in 2012 was about $70 trillion.

Shallow waters in the Arctic Ocean
Shallow waters and little hydroxyl

The danger is particularly high in the shallow seas that are so prominent in the Arctic Ocean, as illustrated by the light blue areas on the image on the right, from an earlier post.

Much of the waters in the Arctic Ocean are less than 50 m deep. Being shallow makes waters prone to warm up quickly during summer temperature peaks, allowing heat to penetrate the seabed.

This can destabilize hydrates and methane rising through shallow waters will then also enter the atmosphere more quickly, as it rises abruptly and in plumes.

Elsewhere in the world, releases from hydrates underneath the seafloor will largely be oxidized by methanotroph bacteria in the water and where methane does enter the atmosphere, it will quickly be oxidized by hydroxyl. In shallow waters, however, methane released from the seabed will quickly pass through the water column.

Large abrupt releases will also quickly deplete the oxygen in the water, making it harder for bacteria to break down the methane.

Very little hydroxyl is present in the atmosphere over the poles, as illustrated by the image on the right, showing global hydroxyl levels, from an earlier post.

In case of a large abrupt methane release from the Arctic Ocean, the little hydroxyl that is present in the atmosphere over the Arctic will therefore be quickly depleted, and the methane will hang around for much longer locally than elsewhere on Earth.

Shallow waters make the Arctic Ocean more prone to methane releases, while low hydroxyl levels make that methane that enters the atmosphere in the Arctic will contribute significantly to local warming and threaten to trigger further methane releases.

High levels of insolation in summer in the Arctic

Furthermore, the amount of solar radiation received by the Arctic at the June Solstice is higher than anywhere else on Earth, as illustrated by the image below, showing insolation on the Northern Hemisphere by month and latitude, in Watt per square meter, from an earlier post.

Warm water enters Arctic Ocean from Atlantic and Pacific Oceans

What further makes the situation in the Arctic particularly dangerous is that waters are not merely warmed up from the top down by sunlight that is especially strong over the Arctic Ocean in summer on the Northern Hemisphere, but also by warm water that flows into the Arctic Ocean from rivers and by warm water that enters the Arctic Ocean through the Bering Strait and through the North Atlantic Ocean. The latter danger is illustrated by the image below, from an earlier post.


Feedbacks

Furthermore, there are feedbacks that can rapidly accelerate warming in the Arctic, such as albedo losses due to loss of sea ice and snow cover on land, and changes to the jet stream resulting in more extreme weather. These feedbacks, described in more details at this page, are depicted in the image below.


Methane


Above image shows that methane levels on December 3, 2015, were as high as 2445 parts per billion (ppb) at 469 millibars, which corresponds to an altitude of 19,810 feet or 6,041 m.

The solid magenta-colored areas (levels over 1950 ppb) that show up over a large part of the Arctic Ocean indicate very strong methane releases.

Note there are many grey areas on above image. These are areas where no measurements could be taken, which is likely due to the strength of winds, rain, clouds and the jet stream, as also illustrated by the more recent (December 5, 2015) images on the right.

The polar jet stream on the Northern Hemisphere shows great strength, with speeds as high as 243 mph or 391 km/h (over a location over japan marked by green circle) on December 5, 2015.

So, high methane levels may well have been present in these grey areas, but didn't show up due to the weather conditions of the moment.

Furthermore, the white geometric areas are due the way the satellite takes measurements, resulting in areas that are not covered.

Finally, it should be noted that much of the methane will have been broken down in the water, before entering the atmosphere, so what shows up in the atmosphere over the Arctic is only part of the total amount of methane that is released from the seafloor.

In conclusion, the high methane levels showing up over the Arctic indicate strong methane releases from the seafloor due to warm waters destabilizing sediments that contain huge amounts of methane in the form of free gas and hydrates.

Climate Plan

As global warming continues, the risk increases that greater ocean heat will reach the Arctic Ocean and will cause methane to be released in large quantities from the Arctic Ocean seafloor. The 2015 El Niño has shown that a huge amounts of ocean heat can accumulate at a depth greater than 100 m (328 ft). Conditions in the Arctic and feedbacks make that methane threatens to be released there abruptly and in large quantities as warming continues.

The situation is dire and calls for comprehensive and effective action as described at the Climate Plan



On November 24, 2015, equatorial waters at ≈100 m (328 ft) depth at 110-135°W were over 6°C (10.8°F) warmer than average...
Posted by Sam Carana on Friday, December 4, 2015

Monday, October 19, 2015

Lucy-Alamo Projects - Hydroxyl Generation and Atmospheric Methane Destruction

As you know the weather is starting to change rapidly for the worse now and I have been working on Arctic methane induced global warming for about 14 years. There are massive deposits of methane gas trapped in the undersea permafrosts in Russian waters and onland in Siberia as well and if the global warming boils of just 10% of what is there, there is enough to cause a Permian style extinction event that humanity will not survive. Some brilliant work on the Arctic methane threat has been done by a Russian scientist Natalia Shakhova and others who indicate that we are in a very perilous position, if we don't find a way of reducing the atmospheric methane and depressurizing the undersea methane to stop the massive methane eruptions there. I and some other workers have designed a radio-laser Atmospheric methane destruction system based on the early Russian radio-wave induced conversion of methane to nano-diamonds. This radio-laser system can be installed on nuclear powered boats such as the 40 Russian Arctic ice breakers and start immediate work on destroying the atmospheric methane clouds that are building up in the Arctic. An abstract about the system is attached and it has been accepted for presentation at a congress of the American Meteorological Society to be held on January 10 - 14, 2016 at New Orleans in Louisiana, U.S.A. This system should be mounted on the nuclear icebreakers and used onshore. Once the methane is brought under control there should be a reduction in the massive fire hazards, heat waves and severe storms systems that are plaguing Russia and the rest of the world.

Yours sincerely,

Malcolm P.R. Light
Earth Scientist

The Abstract follows:-
No. 275345 Lucy - Alamo Projects - Hydroxyl Generation and Atmospheric Methane Destruction.
by
Malcolm P.R. Light (Dr)
Retired, Cortegana, Spain

Congress of the American Meteorological Society, Wednesday 13, January, 2016

Methane formed by organisms in the water becomes trapped in the fabric of water ice crystals when it freezes and is stable below about 300 metres depth in the Arctic Ocean and on the shallow East Siberian Arctic Shelf. There are such massive methane reserves below the Arctic Ocean floor, that they represent 100 times the amount, that is required to cause a Permian style major extinction event, should the subsea Arctic methane be released into the atmosphere because of methane's giant global warming potential (100 to 1000 times CO2) over a short time period (Light and Solana, 2012 - 2014, Carana 2012 - 2014). There are also giant reservoirs of mantle methane, originally sealed in by shallow methane hydrate plugs in fractures cutting the Arctic seafloor and onshore in N. Siberia (Light, 2014, Carana 2013, Light, Hensel and Carana, 2015). The whole northern hemisphere is now covered by a thickening atmospheric methane global warming veil from Arctic methane emissions at the level of the jet streams, which is spreading southwards at about 1 km a day and already totally envelopes the United States (Figure 1). There must therefore be a world-wide effort to capture and thus depressurise the methane in the subsea and surface Arctic permafrost and eradicate the quantities accumulating in the ocean and atmosphere.

Methane produced at the surface diffuses upward and is broken down by photo dissociation (sunlight) and chemical attack by nascent oxygen and hydroxyl (Heicklen, 1967). The Lucy Project is a radio/laser system for destroying the first hydrogen bond in atmospheric methane when it forms dangerously thick global warming clouds over the Arctic (Figure 2, Light & Carana, 2012). It generates similar gas products to those normally produced by the natural destruction of methane in the atmosphere over some 15 to 20 years. Radio frequencies are used in generating nano-diamonds from methane gas in commercial applications over the entire pressure range of the atmosphere up to 50 km altitude (Figure 2, Light and Carana, 2012). Recent experiments have shown that when a test tube of seawater was illuminated by a polarized 13.56 MHZ radio beam, that flammable gases (nascent hydrogen and hydroxyls) were released at the top of the tube (iopscience.iop.org, 2013). In the Arctic Ocean, polarized 13.56 MHZ radio waves will decompose atmospheric humidity, mist, fog, ocean spray and the surface of the waves themselves into nascent hydrogen and hydroxyl over the region where a massive methane torch (plume) is entering the atmosphere, so that the additional hydroxyl produced will react with the rising methane, breaking a large part of it down (Figure 2)(iopscience.iop.org, 2013).

A better system could use Nd: glass heating lasers containing hexagonal neodymium which is stable below 863oC (Krupke 1986 in Lide and Frederickse, 1995). Neodymium glass lasers have extreme output parameters with peak powers near 10 to the power 14 watts when collimated and peak power densities of 10 to the power 18 watts per square cm if focused (Krupke 1986 in Lide and Frederickse, 1995). Velard (2006) states that at the Lawrence Livermore Laboratory, for inertial confinement nuclear fusion, "192 beams of Nd: glass - plate amplifier chains are being used in parallel clusters to generate very high energy (10 kilojoules) at a very high power (>10 power 12 watts) and at the second and third harmonics of the fundamental, with flexible pulse shapes and with sophisticated spectral and spacial on - target laser light qualities". The Nd: glass laser system is more stable and efficient than the longer wavelength CO lasers and shorter wavelength KrF lasers (Velard, 2006).

The three 13.56 MHZ radio transmitters in the Lucy Project (Figure 2) could be replaced by 3 groups of parallel lasers each forming a giant circular flash lamp. Half the Nd: glass lasers in the flash lamp could be tuned to exactly 21 million times the 13.56 MHZ methane destruction/nano-diamond formation frequency (Mitura, 1976). The adjacent alternate lasers will be tuned to a slightly different frequency exactly out of phase with the primary frequency by 13.56 MHZ.The Nd: glass lasers have a wavelength of 1052 nm equivalent to a frequency of 2.85*10 power 8 MHZ. The methane molecule requires 435 kilo-joules per mole to dislodge the first hydrogen proton and an average of 409.3 kilo - joules per mole for the other three protons (Hutchinson, 2014). Hydroxyl requires 493 kilo - joules per mole to generate it from water (Hutchinson, 2014). A set of four focused Nd; glass lasers will have an energy of about 454.5 kilo-joules per mole, and will be strong enough to dislodge the first hydrogen proton from a methane molecule. Of course this can also be achieved by increasing the number of focused lasers to six or eight. Exactly the same neodymium laser system could be shone on the sea surface, at the base of the rising methane cloud, generating hydroxyls and nascent oxygen and thus breaking down the methane. The power source for these radio transmitters/lasers in the Arctic can come from floating or coastal nuclear or gas electric power stations and the transmitters could be located on shore or on boats, submarines, oil-rigs and aircraft. We have only 1 to 5 years to get an efficient methane destruction radio-laser system designed, tested and installed (Lucy and Alamo (HAARP) projects) before the accelerating methane eruptions take us into uncontrollable runaway global warming. Humanity will then be looking at catastrophic storm systems, a fast rate of sea level rise and coastal zone flooding with its disastrous effects on world populations and global stability.


Links


- Lucy-Alamo Projects - Hydroxyl Generation and Atmospheric Methane Destruction, by Malcolm P.R. Light (Dr) Light
https://ams.confex.com/ams/96Annual/webprogram/Paper275345.html

- North Siberian Arctic Permafrost Methane Eruption Vents, by Malcolm P.R. Light, Harold H. Hensel and Sam Carana 

- Poster created for Geophysical Congress on methane hydrates, earthquakes and global warming, Nice, France, 2002, by Malcolm Light and Carmen Solana
http://arctic-news.blogspot.com/p/seismic-activity.html



Poster Presentation at American Meteorological Society's 18th Conference on Atmospheric Chemistry, January 10 - 14,...
Posted by Sam Carana on Monday, October 19, 2015

Friday, January 30, 2015

Why are methane levels over the Arctic Ocean high from October to March?


Water temperatures at different depth

Why are methane concentrations in the atmosphere over the Arctic Ocean so high from October through to March?

The image below, replotted by Leonid Yurganov from a study by Chepurin et al, shows sea water temperature at different depths in the Barents Sea.


Above image illustrates that, while Arctic sea water at the surface reaches its highest temperatures in the months from July to September, water at greater depth reaches its highest temperature in the months from October to March. Accordingly, huge amounts of methane are starting to get released from the Arctic Ocean's seafloor in October.

Surface temperatures in October

As the image below shows, temperature at 2 meters was below 0°C (32°F, i.e. the temperature at which water freezes) over most of the Arctic Ocean on October 26, 2014. The Arctic was over 6°F (3.34°C) warmer than average, and at places was up to 20°C (36°F) warmer than average.
  
Image from 'Ocean temperature rise'
At the same time, continents around the Arctic Ocean are frozen. Surface temperatures over the Arctic Ocean were higher than temperatures on land at the end of October, due to the enormous amounts of heat being transferred from the waters of the Arctic Ocean to the atmosphere. This was the result of ocean heat content, which in 2014 was the highest on record, especially in the Arctic Ocean, which also made that at that time of year the sea ice extent was still minimal in extent and especially in volume. 

Start of freezing period

In October, the Arctic Ocean typically freezes over, so less heat will from then on be able to escape to the atmosphere. Sealed off from the atmosphere by sea ice, greater mixing of heat in the water will occur down to the seafloor of the Arctic Ocean.

Less fresh water added to Arctic Ocean

The sea ice also seals the water of the Arctic Ocean off from precipitation, so no more fresh water will be added to the Arctic Ocean due to rain falling or snow melting on the water. In October, temperatures on land around the Arctic Ocean will have fallen below freezing point, so less fresh water will flow from glaciers and rivers into the Arctic Ocean. At that time of year, melting of sea ice has also stopped, so fresh water from melting sea ice is no longer added to the Arctic Ocean either. 

Rising salt content

As addition of fresh water ends, the salt content of the water in the Arctic Ocean starts to rise accordingly, while the Gulf Stream continues to push salty water into the Arctic Ocean. The higher salt content of the water makes it easier for ice to melt at the seafloor of the Arctic Ocean. Saltier water causes ice in cracks and passages in sediments at the seafloor of the Arctic Ocean to melt, allowing methane contained in the sediment to escape. 

Pingos and conduits. Hovland et al. (2006)
The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past. Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Heat can penetrate cracks and conduits in the seafloor, destabilizing methane held in hydrates and in the form of free gas in the sediments.

Less hydroxyl in atmosphere

Besides heat, open water also transfers more moisture to the air. The greater presence of sea ice from October onward acts as a seal, making that less moisture will evaporate from the water. Less moisture evaporating, together with the change of seasons (i.e. less sunshine) results in lower hydroxyl levels in the atmosphere at the higher latitudes of the Northern Hemisphere, in turn resulting in less methane being broken down in the atmosphere over the Arctic.

Gulf Stream

Malcolm Light writes in this and this earlier posts that the volume transport of the Gulf Stream has increased by three times since the 1940's, due to the rising atmospheric pressure difference set up between the polluted, greenhouse gas rich air above North America and the marine Atlantic Air. 

The increasingly heated Gulf Stream with its associated high winds and energy rich weather systems then flows NE to Europe where it is increasingly pummeling Great Britain with catastrophic storms, as also described in this earlier post, which adds that faster winds means more water evaporation, and warmer air holds more water vapor, so this can result in huge rainstorms that can rapidly devastate the integrity of the ice. The image below further illustrates the danger of strong winds over the North Atlantic reaching the Arctic.


Branches of the Gulf Stream then enter the Arctic and disassociate the subsea Arctic methane hydrate seals on subsea and deep high - pressure mantle methane reservoirs below the Eurasian Basin - Laptev Sea transition. This is releasing increasing amounts of methane into the atmosphere where they contribute to anomalously high local temperatures, greater than 20°C above average.

From: The Biggest Story of 2013
Emissions from North America are - due to the Coriolis effect - moving over areas off the North American coast in the path of the Gulf Stream (see animation on the right).

The Gulf Stream reaches its maximum temperatures off the North American coast in July. It can take almost four months for this heat to travel along the Gulf Coast and reach the Arctic Ocean, i.e. water warmed up off Florida in early July may only reach waters beyond Svalbard by the end of October.

Waters close to Svalbard reached temperatures as high as 63.5°F (17.5°C) on September 1, 2014 (green circle). The image below shows sea surface temperatures only - at greater depths (say about 300 m), the Gulf Stream can push even warmer water through the Greenland Sea than temperatures at the sea surface.


Since the passage west of Svalbard is rather shallow, a lot of this very warm water comes to the surface at that spot, resulting in an anomaly of 11.9°C. The high sea surface temperatures west of Svalbard thus show that the Gulf Stream can carry very warm water (warmer than 17°C) at greater depths and is pushing this underneath the sea ice north of Svalbard.
Through to March the following year, salty and warm water (i.e. warmer than water that is present in the Arctic Ocean) will continue to be carried by the Gulf Stream into the Arctic Ocean, while the sea ice will keep the water sealed off from the atmosphere, so little heat and moisture will be able to be transferred to the atmosphere. 

Start of melting period

This situation continues until March, when the sea ice starts to retreat and more hydroxyl starts getting produced in the atmosphere. Increased sea ice melt and glaciers melt, the latter resulting in warmer water flowing into the Arctic Ocean from rivers, will cause salinity levels in the Arctic Ocean to fall, in turn causing methane levels to fall in the atmosphere over the Arctic Ocean. Furthermore, the water traveling along the Gulf Stream and arriving in the Arctic Ocean in March will be relatively cold.  


References


- Chepurin, G.A., and J.A. Carton, 2012: Sub-arctic and Arctic sea surface temperature and its relation to ocean heat content 1982-2010, J. Geophys. Res.-Oceans., 117, C06019, DOI: 10.1029/2011JC007770. http://onlinelibrary.wiley.com/doi/10.1029/2011JC007770/abstract 

- Combination image created by Sam Carana with Climate Reanalyzer, from: Temperature Rise, http://arctic-news.blogspot.com/2014/10/ocean-temperature-rise.html 

- Submarine pingoes: Indicators of shallow gas hydrates in a pockmark at Nyegga, Norwegian Sea, by Martin Hovland and Henrik Svensen (2006) http://www.sciencedirect.com/science/article/pii/S0025322705003968

- Sea surface temperature west of Svalbard,
created by Sam Carana with
http://earth.nullschool.net


Saturday, April 5, 2014

Like a giant elevator to the stratosphere


Recent research results show that an atmospheric hole over the tropical West Pacific is reinforcing ozone depletion in the polar regions and could have a significant influence on the climate of the Earth.

Potsdam, 3 April 2014. An international team of researchers headed by Potsdam scientist Dr. Markus Rex from the Alfred Wegener Institute has discovered a previously unknown atmospheric phenomenon over the South Seas. Over the tropical West Pacific there is a natural, invisible hole extending over several thousand kilometres in a layer that prevents transport of most of the natural and manmade substances into the stratosphere by virtue of its chemical composition. Like in a giant elevator, many chemical compounds emitted at the ground pass thus unfiltered through this so-called “detergent layer” of the atmosphere. Scientists call it the “OH shield”. The newly discovered phenomenon over the South Seas boosts ozone depletion in the polar regions and could have a significant influence on the future climate of the Earth – also because of rising air pollution in South East Asia.

In tropical thunderstorms over the West Pacific air masses and
the chemical substances they contain are quickly hurled upward
to the edge of the stratosphere. If there are sufficient OH
molecules in the atmosphere, the air is extensively cleaned by
chemical transformation processes. Where OH concentrations are
low, such as those now found in large sections of the tropical
West Pacific, the cleaning capacity of the atmosphere is reduced.
Photo: Markus Rex, Alfred Wegener Institute
At first Dr. Markus Rex suspected a series of flawed measurements. In October 2009 the atmospheric physicist from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) was on board the German research vessel “Sonne” to measure trace substances in the atmosphere in the tropical West Pacific.

Tried and tested a thousand times over, the ozone probes he sent up into the tropical sky with a research balloon every 400 kilometres reported – nothing.

Or to be more accurate: almost nothing. The ozone concentrations in his measurements remained nearly constantly below the detection limit of approx. 10 ppbv* in the entire vertical range from the surface of the Earth to an altitude of around 15 kilometres. Normally ozone concentrations in this part of the atmosphere are three to ten times higher.

Although low values at an altitude of around 15 kilometres were known from earlier measurements in the peripheral area of the tropical West Pacific, the complete absence of ozone at all heights was surprising. However, after a short period of doubt and various tests of the instruments it dawned on the worldwide recognised ozone specialist that he might be onto a phenomenon yet unknown to science. A few research years later and after the involvement of other colleagues came confirmation: Markus Rex and his team on board the “Sonne” had tracked down a giant natural hole over the tropical South Seas, situated in a special layer of the lower atmosphere known as the “OH shield”. The research results on the newly discovered OH minimum will be published soon in the journal “Atmospheric Chemistry and Physics”, with the Institute of Environmental Physics of the University of Bremen and other international research institutions as partners.
Nearly all chemical substances produced by people, animals,
plants, algae or microorganisms on the ground or in the oceans
react quickly with OH and break down in this process. During this
chemical self-cleaning process substances that are not easily
water-soluble are transformed into water-soluble products and
then washed out by precipitation. Through this mechanism OH
molecules remove most substances from the atmosphere.
The OH molecule is therefore also called the detergent of the
atmosphere. Only extremely long-lived chemical compounds,
such as methane or CFCs, also known as "ozone killers", can
rise through the OH shield into the stratosphere.
Graphics: Markus Rex, Alfred Wegener Institute
“Even though the sky appears to be an extensively uniform space for most people, it is composed of chemically and physically very different layers,” Markus Rex explains the complex makeup of the atmosphere.

The air layers near the ground contain hundreds or even thousands of chemical compounds. This is why winter and spring, mountains and sea, city and forests all have a distinct smell. The great majority of these substances are broken down into water-soluble compounds in the lower kilometres of the atmosphere and are subsequently washed out by rain.

Since these processes require the presence of a certain chemical substance, the so called hydroxyl (=OH) radical, this part of the atmosphere is called the “OH shield”. It acts like a huge atmospheric washing machine in which OH is the detergent.

The OH shield is part of the troposphere, as the lower part of the atmosphere is called. “Only a few, extremely long-lived compounds manage to make their way through the OH shield,” says Rex, “then they also get through the tropopause and enter the stratosphere.” Tropopause refers to the boundary layer between the troposphere and the next atmospheric layer above it, the stratosphere. Particularly substances that enter the stratosphere unfold a global impact. The reason for this is that once they have reached the stratosphere, their degradation products remain up there for many years and spread over the entire globe.

Extremely long-lived chemical compounds find their way to the stratosphere, even where the OH shield is intact. These include methane, nitrous oxide (“laughing gas”), halons, methyl bromide and chlorofluorocarbons (CFCs), which are notorious as “ozone killers” because they play a major role in ozone depletion in the polar regions.

Location and extent of low ozone concentrations and thus
of the OH hole over the West Pacific. Fig. (a) shows the
region of origin of the air in the stratosphere, Fig. (b) ozone
sonde measurements (dots) and satellite measurements
(coloured map) of the total amount of ozone in the
tropospheric column of air and Fig. (c) the total amount of
OH in the tropospheric column of air calculated with a model.
Graphics: Markus Rex, Alfred Wegener Institute.
After many years of research scientists now understand the complicated process of stratospheric ozone depletion very well.

“Nevertheless measured ozone depletion rates were often quite a bit larger than theoretically calculated in our models,” Markus Rex points out a long unsolved problem of atmospheric research.

“Through the discovery of the OH hole over the tropical West Pacific we have now presumably made a contribution to solving this puzzle.”

And at the same time discovered a phenomenon that raises a number of new questions for climate policy.

Researchers are now tackling these questions in a new research project funded by the EU with around 9 million euros, i.e. “StratoClim”, which is coordinated by the Alfred Wegener Institute. Within this project a new monitoring station will be established in the tropical Westpacific, together with the Institute of Environmental Physics at the University of Bremen.

“We have to realise,” reminds the Potsdam atmospheric physicist, “that chemical compounds which enter the stratosphere always have a global impact.” Thanks to the OH hole that the researchers discovered over the tropical Pacific, greater amounts of brominated hydrocarbons can reach the stratosphere than in other parts of the world. Although their ascent takes place over the tropical West Pacific, these compounds amplify ozone depletion in the polar regions. Since scientists identified this phenomenon and took it into account in the modelling of stratospheric ozone depletion, their models have corresponded excellently with the actually measured data.

However, it is not only brominated hydrocarbons that enter the stratosphere over the tropical West Pacific. “You can imagine this region as a giant elevator to the stratosphere,” states Markus Rex using an apt comparison. Other substances, too, rise here to a yet unknown extent while they are intercepted to a larger extent in the OH shield elsewhere on the globe. One example is sulphur dioxide, which has a significant impact on the climate.

Sulphur particles in the stratosphere reflect sunlight and therefore act antagonistically to atmospheric greenhouse gases like CO2, which capture the heat of the sun on the Earth. To put it simply, whereas greenhouse gases in the atmosphere heat the globe, sulphur particles in the stratosphere have a cooling effect. “South East Asia is developing rapidly in economic terms,” Markus Rex explains a problem given little attention to date. “Contrary to most industrial nations, however, little has been invested in filter technology up to now. That is why sulphur dioxide emissions are increasing substantially in this region at present.”

This is how air reaches the stratosphere. Through the rapid
upward transport in tropical thunderstorms they reach an area
of slow large-scale ascent and rise from there through the
tropopause into the stratosphere over the course of weeks.
This process is most pronounced during northern hemispheric
winter. Model calculations show that, during this season, this
process mainly takes place over the tropical West Pacific. Due
to the formation of cirrus (= ice) clouds in the extremely cold
tropical tropopause, a large portion of the water-soluble
chemical substances is removed from the air and cannot reach
the stratosphere. OH molecules transform water-insoluble into
water-soluble compounds. Hence, if the concentration of OH
molecules along the dotted transport pathways shown above
is high only few chemical compounds make it into the
stratosphere. Conversely, the lower the OH concentration is
along the transport pathways, the more chemical
compounds enter the stratosphere.
Graphics: Yves Nowak, Alfred Wegener Institute.
If one takes into account that sulphur dioxide may also reach the stratosphere via the OH hole over the tropical West Pacific, it quickly becomes obvious that the atmospheric elevator over the South Seas not only boosts ozone depletion, but may influence the climate of the entire Earth. In fact, the aerosol layer in the stratosphere, which is also composed of sulphur particles, seems to have become thicker in recent years. Researchers do not know yet whether there is a connection here.

But wouldn’t it be a stroke of luck if air pollutants from South East Asia were able to mitigate climate warming? “By no means,” Markus Rex vigorously shakes his head. “The OH hole over the South Seas is above all further evidence of how complex climate processes are. And we are still a long way off from being in a position to assess the consequences of increased sulphur input into the stratosphere. Therefore, we should make every effort to understand the processes in the atmosphere as best we can and avoid any form of conscious or unconscious manipulation that would have an unknown outcome.”

Background:

Why is there an OH hole over the West Pacific?
The air in the tropical West Pacific is extremely clean. Air masses in this area were transported across the expanse of the huge Pacific with the trade winds and for a long time no longer had contact with forests or other land ecosystems that produce innumerable short-lived hydrocarbons and release them into the air. Under these clean air conditions OH is formed from ozone through chemical transformation to a great degree. If there is hardly any ozone in the lower atmosphere (= troposphere), as is the case in the West Pacific, only little OH can be formed. The result is an OH hole.

The graph shows ozone profiles measured in three different
marine regions: the tropical Atlantic, the tropical West Pacific
and the West Pacific outside the tropics. The red curve clearly
shows that ozone is consistently very low up to an altitude of
15 kilometres over the tropical West Pacific. In the other
regions the ozone concentrations are in a range typical
for the troposphere.
Graphics: Markus Rex, Alfred Wegener Institute
Ozone, in turn, forms in the lower atmosphere only if there are sufficient nitrogen oxides there. Large amounts of nitrogen oxide compounds are produced in particular by intensive lightning over land.

However, the air masses in the tropical West Pacific were not exposed to any continental tropical storms for a very long time during their transport across the giant ocean. And the lightning activity in storms over the ocean is relatively small. At the same time the lifetime of atmospheric ozone is short due to the exceptionally warm and moist conditions in the tropical West Pacific. In this South Sea region the surface temperatures of the ocean are higher than anywhere else on our planet, which makes the air not only quite warm, but also quite moist.

The ozone is thus quickly lost, especially directly above the water. And due to the lack of nitrogen oxide compounds little ozone is subsequently formed. Rapid vertical mixing in the convection areas that exist everywhere over the warm ocean and in which the warm air rises takes care of the rest. Finally, there is no more ozone in the entire column of air in the troposphere. And without ozone (see above) the formation of OH is suppressed.

What impact does the OH hole over the West Pacific have?
The illustration shows the average lifetime of sulphur dioxide
and some brominated hydrocarbons for normal conditions
over the tropical Atlantic and for conditions of reduced
OH-concentrations over the tropical West Pacific.
Graphics: Markus Rex, Alfred Wegener Institute
The OH molecule is also called the detergent of the atmosphere. Nearly all of the thousands of different chemical substances produced by people, animals, plants, fungi, algae or microorganisms on the ground or in the oceans react quickly with OH and break down in this process. Therefore, virtually none of these substances rises into the stratosphere. In the area of the OH hole, however, a larger portion of this varied chemical mix can enter the stratosphere.

And local emissions may unfold a global impact, especially if they make it to the stratosphere. There they spread globally and can influence the composition of the air for many years – with far-reaching consequences for ozone chemistry, aerosol formation and climate.

Why wasn’t the OH hole discovered earlier?
The tropical West Pacific is one of the most remote regions on our planet. That is why extensive measurements of the air composition have yet to take place in this area. There is also a considerable gap in the otherwise dense network of global ozone measurement stations here. Even in the past measurements from the peripheral sections of the now investigated region showed minimal ozone values in the area of the upper troposphere, but not the consistently low values that have now been found across the entire depth of the troposphere. The newly discovered phenomenon reveals itself in its full scope only through the measurements that were conducted to such an extensive degree for the first time and was thus not able to be grasped at all previously.

*One part of ozone per billion by volume (ppbv) means there is one ozone molecule for every billion air molecules.

Monday, August 12, 2013

More on Wildfires


Previous posts have highlighted the huge amounts of carbon dioxide, methane and soot being emitted as a result of wildfires. Apart from this, there are further important pollutants to consider in regard to their potential to contribute to warming, especially at high latitudes.

The image below, dated August 7, 2013, and kindly supplied by Leonid Yurganov, shows high levels of carbon monoxide as a result of wildfires in Siberia, reaching high up into the Arctic all the way to Greenland. 

[ click on image to enlarge ]
Formation of tropospheric ozone mostly occurs when nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs) react in the atmosphere in the presence of sunlight. NOx, CO, and VOCs are therefore called ozone precursors. Apart from a health hazard, tropospheric ozone is an important greenhouse gas. Furthermore, carbon monoxide emissions contribute to hydroxyl depletion, thus extending the lifetime of methane.

While there appears to be little or no carbon dioxide from wildfires over North America on the above August 7 image, there are many recent wildfires raging over the North American continent, as illustrated by the August 12 map below, from Wunderground

[ click on image to enlarge ]
This point is illustrated even better on the image below [added later, ed.] showing a composite image with carbon monoxide over July 3-13, 2013. Carbon monoxide resulting from wildfires in Canada is seen crossing the Atlantic Ocean, due to the Coriolis effect, as well as reaching Greenland in large amounts.

[ click on image to enlarge ]


Related

- Wildfires even more damaging
http://arctic-news.blogspot.com/2013/07/wildfires-even-more-damaging.html

- The Threat of Wildfires in the North
http://arctic-news.blogspot.com/2013/06/the-threat-of-wildfires-in-the-north.html

- Wildfires in Canada affect the Arctic
http://arctic-news.blogspot.com/2013/07/wildfires-in-canada-affect-the-arctic.html

Sunday, March 18, 2012

Warming in the Arctic

Note: this is a 3.4 MB animation that may take some time to fully load. 

Loss of snow and ice can change local temperatures significantly, especially in April/May.

The changes contribute to accelerated warming in the Arctic, which - as the image left shows - is projected to reach 10 degrees Celsius in the 2040s.

Temperatures could rise even faster in the Arctic as methane gets released from hydrates. 

Methane's global warming potential is 105 times as much as carbon dioxide over a 20-year period, and even higher over a shorter period. 

How much methane is there?


Of all the methane located in the Arctic, 50 Gt is ready for abrupt release at any time in the ESAS alone (squared area, image left). 

Such a release would dwarf warming by carbon dioxide from fossil fuels (~ 33 Gt/y), given methane's high immediate global warming potential. 

When released from a hydrate, much of the methane will remain concentrated locally, amplifying local warming.  

For this reason, even a much smaller release could already cause dramatic local warming. There are further reasons why this is the case.  

Such a release will extend methane's lifetime, while lack of hydroxyl in the Arctic (image left) could further make the methane stay there for decades, at a high global warming potential, while triggering further releases.

Meanwhile, rising temperatures will cause firestorms to rage over the tundras of Canada and Siberia, releasing huge amounts of greenhouse gases and soot from peatlands and soil carbon. 

The recent firestorms in Russia provide a gloomy preview of what could happen as temperatures keep rising in the Arctic.  

The image below illustrates how much organic carbon is present in the melting permafrost.  

Much of the soot from firestorms in Siberia could settle on the ice in the Himalaya Tibetan plateau, melting the glaciers there and causing short-term flooding followed by rapid decrease of the flow of ten of Asia’s largest river systems that originate there, with more than a billion people’s livelihoods depending on the continued flow of this water.