Arctic Sea Ice : Forum

Cryosphere => Antarctica => Topic started by: Apocalypse4Real on February 28, 2013, 03:07:53 PM

Title: Antarctic Methane Concentrations
Post by: Apocalypse4Real on February 28, 2013, 03:07:53 PM
Over the last couple of weeks, higher levels of methane have started to appear over Antarctica.

I have updated the METOP 2/B images through February 26, 2013 pm. They reveal that there is a significant area of high methane concentration over Antarctica.

See: https://sites.google.com/site/a4r2013metop2iasich4co2/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on February 28, 2013, 04:02:42 PM
A4R,

Thanks of this update.  Historically, natural methane emissions (from hydrate decomposition) have been coming from the Antarctic Peninsula for some years now (as it is warming so quickly), and your figures makes it look like these new emissions are also down wind of the Antarctic Peninsula.  Maybe in a few years this will start happening in the Amundsen Sea Embayment as the glacier retreat exposing hydrate bearing sediment.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on March 03, 2013, 02:08:33 PM
A4R,

As I noted yesterday in my "Collapse Main Period 2060 to 2100" thread, I am now concerned that the Antarctic methane emissions that you identified could possibly be coming from a degradation of the Weddell Sea Embayment, WSE, ice sheet (due to a pulse of warm Circumpolar Deep Water, CDW) exposing methane hydrates in the seafloor.  It this is true, then this would be much more serious than methane emissions from the Antarctic Peninsula, due to the amount of ice sheet mass around the WSE, which is enough to raise sea levels by about 0.34 m, by themselves (and the loss of the WSE ice sheets would help destabilize adjoining ice features in both the WAIS and the EAIS).
Title: Re: Antarctic Methane Concentrations
Post by: sg_smith on April 07, 2013, 01:22:33 PM

I have been looking at the temperature anomalies shown on arctic news site on march 22, and  comparing  them  with the methane anomalies.  I think it is interesting that the methane anomalies are coming from and or near the area with the coldest (-10) degrees.  I thought they would be from the warmest areas  :).

Cheers
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on April 14, 2013, 07:28:21 PM
For those who have not visited A4R's website recently, he has posted methane concentrations including for Antarctica thru March 31, 2013 at the following site:

https://sites.google.com/site/a4r2013metop2iasich4co2/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb

Looking at the pattern of methane atmospheric concentration around the Antarctic it appears to me that it is occurring in an area where the warm Circumpolar Deep Water, CDW, has recently migrated southward where it may have encountered (and thermally destabilized) ocean sediment containing methane hydrates.
Title: Re: Antarctic Methane Concentrations
Post by: Donna on April 15, 2013, 12:10:48 AM
For those who have not visited A4R's website recently, he has posted methane concentrations including for Antarctica thru March 31, 2013 at the following site:

https://sites.google.com/site/a4r2013metop2iasich4co2/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb

Looking at the pattern of methane atmospheric concentration around the Antarctic it appears to me that it is occurring in an area where the warm Circumpolar Deep Water, CDW, has recently migrated southward where it may have encountered (and thermally destabilized) ocean sediment containing methane hydrates.
 

AbruptSLR - A4R wrote the following on the Arctic Methane Release thread -   

Quote
I have started posting the METOP2 IASI CH4 for April to June 2013  on a new website due to space constraints.

See: https://sites.google.com/site/a4r2013metop2ch4aprjun/
 

Sorry but I don't know how to link to a particular comment  :-\
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on April 15, 2013, 12:22:46 AM
Donna,

Thank you. 

The April atmospheric methane concentrations in portions of the Antarctic look higher than those currently in the Arctic, per this link: 

https://sites.google.com/site/a4r2013metop2ch4aprjun/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb
 
 
Title: Re: Antarctic Methane Concentrations
Post by: Donna on April 15, 2013, 04:22:17 AM
The April atmospheric methane concentrations in portions of the Antarctic look higher than those currently in the Arctic, per this link: 

https://sites.google.com/site/a4r2013metop2ch4aprjun/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb (https://sites.google.com/site/a4r2013metop2ch4aprjun/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb)
 
 

Indeed they do. If the highs listed are from there then they are higher than the alarming levels in Svalbard in January.  I wish this site - http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=HBA&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=HBA&program=ccgg&type=ts)  were up to date. 

I wonder if this has caught the attention of Dr. Leonid Yurganov, though I know his work in the past has been in the arctic.  If you learn of a site with more exact levels or more information please share.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on April 15, 2013, 05:07:31 PM
For convenience I have posted the Antarctic atmospheric methane concentration figure linked by Donna, from the Halley Research Station, run by the British Antarctic Survey; which is located on the Brunt Ice Shelf floating on the Weddell Sea.  Although this data ends in Dec 2011, it indicates a troubling trend of increasing methane concentration in the Antarctic atmosphere.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on April 15, 2013, 06:51:37 PM
Donna,

Here is a link to slightly newer atmospheric methane concentration data (from the South Pole Station, see attached figure) from a different part of the website that you referenced in your post at:

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)

This graph shows a similar trend at that from the Halley Station, but as the South Pole is further from the Southern Ocean the data trend is less pronounced.
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on April 20, 2013, 01:13:25 AM
Donna and Abrupt SLR,

Dr Yurganov is aware of what I am posting. We have had a brief discussion of the observations.

I'll add more over the weekend, work has been crazy and I am behind on posting. I'll keep you apprised and may add a couple of Google Earth images with an Antarctic perspective to give us a better way of viewing the concentrations.

A4R
Title: Re: Antarctic Methane Concentrations
Post by: Donna on April 20, 2013, 04:43:03 AM
Donna and Abrupt SLR,

Dr Yurganov is aware of what I am posting. We have had a brief discussion of the observations.

I'll add more over the weekend, work has been crazy and I am behind on posting. I'll keep you apprised and may add a couple of Google Earth images with an Antarctic perspective to give us a better way of viewing the concentrations.

A4R
 

Wow! This is fantastic. Thank you so much A4R!  Really looking forward to your posts when you have time.
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on April 21, 2013, 07:12:11 PM
To demonstrate the Antarctic methane concentrations, attached is the April 12 2013 pm 586 mb CH4 concentrations, which were as high as 2163 ppbv.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on April 21, 2013, 07:22:29 PM
A4R,

Thanks for your great posts on Antarctic Atmospheric Methane Concentrations. 

The attached figure shows the bathymetry of the Southern Ocean; which, indicates that the submerged Kerguelen Plateau has a depth of about -700m, which indicates that any methane hydrates present there would be directly exposed to the measured recent increases in water temperatures of the circumpolar deep water, CDW; which could be contributing to the decomposition of the methane hydrates and consequently contributing to plumes of methane gas emissions measured to be occurring in this area.

Furthermore, this post refers to images on A4R's website before April 20, 2013 which show the high methane concentrations over the Southern Ocean; while A4R's posted image immediately above shows areas of very high atmospheric methane concentration over the East Antarctic Ice Sheet, EAIS, itself; for which I have no idea how this methane got to where it is indicated unless the coriolis effect drove circumpolar offshore winds on to the EAIS, carrying the methane with it.
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on April 22, 2013, 01:41:35 PM
Abrupt SLR,

I'll post more images later, I am buried in the last week before finals, then finals/graduation  next week. There is alot more to add, but no time at the moment.

A4R.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 07, 2013, 05:01:29 PM
I thought that I would post this accompanying methane hydrate stability graph including the influence of saltwater on hydrate stability.  To me this chart clearly indicates that natural gas hydrates in marine sediment in the Southern Ocean at depths shallower than about 350m (such as in the Kerguelen Plateau, shown in my earlier post, or most of the continental shelf) are subject to decomposition as the CDW warms above its historical values.  This curve also indicates to me that most of any hydrates below the Antarctic Ice Sheet, AIS, at depths deeper than about 350m are probably relatively stable even if the ice sheet above then thins due to ice mass loss.
Title: Re: Antarctic Methane Concentrations
Post by: Omar on May 14, 2013, 04:46:57 PM
At first I thought the methane was coming from subsea clathrates, but if it was from subsea clathrates and then transported inland, it would have appeared on 800hPa - 1000hPa mapping. Maybe IASI can't detect methane effectively at those pressures... That's a question for Yurganov (AFR, could you ask him?).

Anyway, I'm no scientist and have no scientific background, but I've been following daily the methane levels in Antarctica  for the last couple of months and it seems to be coming from East Antarctica itself. After reading http://www.dailykos.com/story/2013/04/10/1200602/-The-Antarctic-Half-of-the-Global-Thermohaline-Circulation-Is-Faltering, (http://www.dailykos.com/story/2013/04/10/1200602/-The-Antarctic-Half-of-the-Global-Thermohaline-Circulation-Is-Faltering,) I thought the methane release could have happened on subsea clathrates and winds could have pushed the methane inland, but it seems odd for methane to flow against the wind direction consistently for two months, and, most importantly, there's no methane whatsoever detected at sea level 800hPa+...

The detected methane really seems to be consistent starting at around 650hPa to 670hPa. At the current temperatures in Antarctica of -58F and dewpoint of -64F the elevation would be approximately 1600 to 1900 meters; and the highest levels of methane are found at 586 hPa / around 3000 meters.

What I'm about to say sounds like nosense even to a noob like me, but could it be possible that there are deep fractures in the East Antarctic Ice Sheet that are causing extensive methane venting? After all, the area where the methane is being detected seems to follow pretty much the elevation of the area.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 14, 2013, 05:29:55 PM
Omar,

While would be better for A4R to respond about the accuracy of Yurganov's methane readings, I will make the following observations:

- Regarding the elevations that you posted for the methane concentration readings, per the attached image, ice sheets are present in the EAIS almost every where between el 1600 and 1900m (also note how thick the ice is in the EAIS which has bearing on the probability of any crevasses extending all the way to the bed elevation (see the next point).

- As methane hydrates are stable at the pressure/temperature levels present in Antarctica, it would not matter whether there are crevasses in the ice sheets, as no significant amount of methane gas could vent from them as the stable hydrates are the only likely source of methane (unless you think that large fields of free gas are venting).

-  I suspect that due to the constant circumpolar winds, that the normally low pressures in the South Pole area must trap methane gas over Antarctica, where the very low temperatures probably slows the rate of chemical reduction of the methane to CO2.  Thus this high methane concentration over Antarctica may not be due to high rates of active venting but rather due to a slow accumulation of methane from adjoining areas at a rate that is faster than either the rates of dissipation and chemical reduction.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 14, 2013, 06:06:28 PM
I thought that I should provide the attached image illustrating the "Clathrate Gun" mechanism for continental slope instability for releasing methane from methane hydrates from the sea floor.  Such a mechanism makes is more likely, in my opinion, for the atmospheric methane shown by A4R, to come (gradually from multiple ventings) from marine sources, rather than from the Antarctic continent.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 16, 2013, 12:25:07 AM
I think that looking at the attached image of the wind pattern for May 16 2013 from http://www.weather-forecast.com/maps/Antarctica (http://www.weather-forecast.com/maps/Antarctica)
I can imagine how it might be possible for methane gas from destabilized offshore hydrates could drift over the continent and then become trapped (much like the hydroclorofluorocarbon molecules that degraded the Antactic ozone layer).

Also see A4R's latest methane concentration posts at:

https://sites.google.com/site/a4r2013metop2ch4aprjun/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb (https://sites.google.com/site/a4r2013metop2ch4aprjun/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb)
Title: Re: Antarctic Methane Concentrations
Post by: Omar on May 16, 2013, 04:11:11 PM
Thank you! I really hope you're right and the instrument is no good under 1500 meters.

Actually not only I agree with your arguments, but your rationale is exactly where I started. Based on melting maps, my initial hypothesis was that the methane was coming somewhere around Prydz Bay, so I started looking at 10 or more of the IASI graphs at different pressures every day for the last couple of months looking at the methane, at winds, reading papers, etc. trying to pinpoint the source, but IASI just won't show methane nowhere near the coast.

Every day since the beginning of the release, the lowest altitude readable graphs of methane from Antarctica (where the instrument actually picked up methane) have way less methane that the area at 3000 meters, and they aren't close to the coast either.

I'm convinced that at this point either IASI can't see the methane coming up from under 1000 meters (which has huge implications since IASI is pretty much the only instrument available to the community), or the methane is being generated at high altitudes.

Let me show you the inconsistency coming from the instrument readings:

I may be completely off, but this is what I'm using to convert hPa to elevation: http://www.csgnetwork.com/densaltcalc.html (http://www.csgnetwork.com/densaltcalc.html)

and I'm taking the temperature and dew point from the amundsen station from here: http://www.timeanddate.com/weather/antarctica/south-pole (http://www.timeanddate.com/weather/antarctica/south-pole)

To look at the levels of methane for yesterday, this is the IASI page for 12-24: http://www.osdpd.noaa.gov/IASI/html/M2/RP/mrm_t2.html (http://www.osdpd.noaa.gov/IASI/html/M2/RP/mrm_t2.html)

Now here's the thing that has been puzzling me (and trust me, it's been like this every day since beginnings of February):

Methane at 586hPa / 3158.5 meters (2190ppb today!): http://www.osdpd.noaa.gov/IASI/img/t2/D1/mr_ch4.080.gif (http://www.osdpd.noaa.gov/IASI/img/t2/D1/mr_ch4.080.gif)

Methane at 695hPa / 1475.3 meters: http://www.osdpd.noaa.gov/IASI/img/t2/D1/mr_ch4.085.gif (http://www.osdpd.noaa.gov/IASI/img/t2/D1/mr_ch4.085.gif)

You can see better the contour of Antarctica as picked up by IASI here: http://www.osdpd.noaa.gov/IASI/img/t2/D1/mr_ch4.005.gif (http://www.osdpd.noaa.gov/IASI/img/t2/D1/mr_ch4.005.gif)

And even though it's of no relevance, I've been looking at the ground altitude here (same Mercator projection as IASI, makes it easier to place markers by eyeballing it): http://www.daftlogic.com/sandbox-google-maps-find-altitude.htm (http://www.daftlogic.com/sandbox-google-maps-find-altitude.htm) . I place a lot of markers roughly on the places where the yellow methane emissions are to compare if the elevation matches the hPa. I've found that the elevation on the ground actually matches the elevation by IASI. Again, it doesn't mean anything because methane could be close to the ground regardless of the source.

Your arguments make all the sense in the world and actually I've been trying to prove that is coming from the sea from February, but the instrument just won't help.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 16, 2013, 05:15:59 PM
Omar,

As I have no meterological training, I can make no expert comments on your methodology or on the IASI accuracy; but I will say that in the in the two attached IASI images for 416mb and 487mb that it appears to me that the concentrated methane is near the coast by the Amery Ice Shelf in the Australian sector; where in my opinion it could by been blown by the offshore circumpolar winds from points to the west (i.e. from the Weddell gyre area that I have noted is recently entraining warm CDW from the ACC (Antarctic Circumpolar Current) and bringing a warm stream of CDW in contact with the continental shelf in the Queen Maud Land (or Norwegian sector), which is another possible source of degrading marine methane hydrates.  If the methane leaks from the ocean are low volume it is possible that the IASI reading only show the high concentrations at higher altitudes where it is colder (thus slowing the chemical process that reduces methane to CO2, thus allowing the methane concentrations to accumulate and to remain high for long periods of time.  Again these are only my thoughts.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 16, 2013, 05:35:38 PM
To help clarify my point about warm CDW water entering the Weddell Gyre from the north and then traveling along the coast of the Queen Maud Land, please see the attached figure from the following website for the Andrex project that is actively monitoring this behavior:

http://www.noc.soton.ac.uk/ooc/PROJECTS/andrex/ (http://www.noc.soton.ac.uk/ooc/PROJECTS/andrex/)

The caption for the figure from the Andrex website is:

"Schematic of the circulation in the Weddell Sea (in black). The red arrows represent the escape route from the Weddell Sea. The white arrows are the eastern branches of the Weddell Gyre."

Furthermore, if it is not clear, in the image the white arrows should indicate warm CDW entrained in the eastern end of the Weddell Gyre from the ACC to the north.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 17, 2013, 12:29:13 AM
As a continuation of the Methane Concentration readings that I posted in this thread on April 15, 2013, I attached NOAA's South Pole flask readings for January 2013 from:

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts%5dhttp://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts%5dhttp://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)

This data does not show any significant changes (only the normal seasonal drift).
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 26, 2013, 03:30:42 PM
The first attached image from NOAA on May 25, 2013 of atmospheric methane concentration at 469 mb; which shows a continuingly (and disturbingly) high concentration trend as indicated by the second image from Sam Carana (who belongs to a controversial group concerned about the risks of abrupt methane releases).  As I find it difficult to image a biological source for this pattern of Antarctic atmospheric methane concentration; I continue to suspect a marine sediment methane hydrate source (triggered by the local warming of the marine by warm CDW coming south from the ACC on the eastern side of the Weddell Gyre).
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 01, 2013, 01:42:42 AM
The attached image indicates that the high atmospheric methane concentrations at 586mb over the Antarctic are continuing and are some of the highest concentrations in the world.
Title: Re: Antarctic Methane Concentrations
Post by: Pmt111500 on June 01, 2013, 07:03:04 AM
The only biological source I can come up with could be that some huge algal bloom has died and entered in to deep circulation on a particularly deoxygenized spot. What I'd like to see if this is a yearly or rarer occurrence, something like the H2S releases on Namibian coasts that have been going on as long as there have been measurements. That is a huge difference from the rest of the antarctic coast, though.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 01, 2013, 09:04:13 PM
Pmt11500,

While I am an engineer and not a scientist, and while I agree that it would be good for researchers to track-down any possible biological source for this anomalous methane emission; I am still of the opinion (as stated earlier) that it seems most likely to me that these methane emissions come from the decomposition of marine methane hydrates subjected to seafloor slope instabilities associated with the introduction of relatively warm circumpolar deepwater, CDW, down from the north along the eastern leg of the Weddell Gyre.  I believe that methane emissions frequently come from the breakdown of biological sources beneath fresh water, I believe that CO2 is emitted from the breakdown of biological sources beneath saltwater; as has been indicated by paleo-evidence when increased historical circumpolar wind velocities have increase upwelling around Antarctica which have caused abrupt emissions of biological CO2 in the past.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 04, 2013, 01:02:31 AM
The following abstract indicates that not is a jet of warm CDW current is directed southward from the main ACC (located further to the north); which passes near the Kerguelen Plateau (off the Antarctic coast), and has jets near the bottom that actively cause mixing that could help promote the decomposition of methane hydrates in the local seafloor:

Waterman, Stephanie, Alberto C. Naveira Garabato, Kurt L. Polzin, 2013: Internal Waves and Turbulence in the Antarctic Circumpolar Current. J. Phys. Oceanogr., 43, 259–282.
doi: http://dx.doi.org/10.1175/JPO-D-11-0194.1 (http://dx.doi.org/10.1175/JPO-D-11-0194.1)


"Abstract:  This study reports on observations of turbulent dissipation and internal wave-scale flow properties in a standing meander of the Antarctic Circumpolar Current (ACC) north of the Kerguelen Plateau. The authors characterize the intensity and spatial distribution of the observed turbulent dissipation and the derived turbulent mixing, and consider underpinning mechanisms in the context of the internal wave field and the processes governing the waves’ generation and evolution.
The turbulent dissipation rate and the derived diapycnal diffusivity are highly variable with systematic depth dependence. The dissipation rate is generally enhanced in the upper 1000–1500 m of the water column, and both the dissipation rate and diapycnal diffusivity are enhanced in some places near the seafloor, commonly in regions of rough topography and in the vicinity of strong bottom flows associated with the ACC jets. Turbulent dissipation is high in regions where internal wave energy is high, consistent with the idea that interior dissipation is related to a breaking internal wave field. Elevated turbulence occurs in association with downward-propagating near-inertial waves within 1–2 km of the surface, as well as with upward-propagating, relatively high-frequency waves within 1–2 km of the seafloor. While an interpretation of these near-bottom waves as lee waves generated by ACC jets flowing over small-scale topographic roughness is supported by the qualitative match between the spatial patterns in predicted lee wave radiation and observed near-bottom dissipation, the observed dissipation is found to be only a small percentage of the energy flux predicted by theory. The mismatch suggests an alternative fate to local dissipation for a significant fraction of the radiated energy."
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 13, 2013, 03:15:31 PM
You can see from the first attached NOAA image of atmospheric methane concentrations, that the values over East Antarctica (here taken at 525 mb) continue to be the highest values in the atmosphere.

Furthermore, the second image shows a deep AABW current near the Kerguelen Plateau (off the East Antarctic coast), circa 2010.  This Antarctic Bottom Water, AABW, current probably originates near the Moscow University Ice Shelf and Totten Glacier, and as discussed elsewhere (the "EAIS" thread, etc), fresh meltwater from the Moscow University Ice Shelf and Totten is reducing the AABW production that feeds into this deep current; which implies that the branch of this AABW current that is shown in the image to travel westard along the coastline south of the Kerguelen Plateau, probably currently has less cold AABW than previously and probably has more warm CDW (than previously).  This double hit of less cold and more warm deep water, maybe resulting in more methane hydrate decomposition that could be steadily supplying small abouts of methane to the atmosphere over the East Antarctic; where the very cold temperatures would slow the chemical reduction of the methane, thus allowing it to accumulate in the high concentrations indicated in the first image.

This concentration of methane ove the East Antarctic is significant because it can contribute to the reduction of the local atmospheric pressure which will result in high circumpolar wind velocities (slowly migrating southward); which accelerates upwelling of warm CDW which results in less AABW and more icemelt.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 17, 2013, 03:11:10 AM
The attached image from Purkey and Johnson 2013, supports my prior statement that the bottom water in the Kerguelen Plateau area is introducing a large amount of heat to the seafloor; where this heat can help to destabilize methane hydrates in the seafloor, particularly around the continental shelf/slope areas.
Title: Re: Antarctic Methane Concentrations
Post by: Bruce Steele on June 17, 2013, 08:18:51 AM
ASLR, in your post #27 you source the AABW to the Moscow University ice shelf and Totten Glacier. I believe the source is probably further east for AABW in the South Australian Basin. The warming and mixing with the CDW probably also occurs at it's source although the PMEL article linked below doesn't specifically address the warming that Purkey focuses on. The heating and potential methane releases may be linked to the changes taking place in the Ross sea?                                                       
  Decadal ventilation and mixing of Indian Ocean waters

Fine, R.A., W.M. Smethie, Jr., J.L. Bullister, M. Rhein, D.-H. Min, M.J. Warner, A. Poisson, and R.F. Weiss

Deep-Sea Res. I, 55, doi: 10.1016/j.dsr.2007.10.002, 20–37 (2008)

Chlorofluorocarbon (CFC) and hydrographic data from the World Ocean Circulation Experiment (WOCE) Indian Ocean expedition are used to evaluate contributions to decadal ventilation of water masses. At a given density, CFCderived ages increase and concentrations decrease from the south to north, with lowest concentrations and oldest ages in Bay of Bengal. Average ages for thermocline water are 0–40 years, and for intermediate water they are less than 10 years to more than 40 years. As compared with the marginal seas or throughflow, the most significant source of CFCs for the Indian Ocean south of 12°N is the Southern Hemisphere. A simple calculation is used to show this is the case even at intermediate levels due to differences in gas solubilities and mixing of Antarctic Intermediate Water and Red Sea Water. Bottom water in the Australia–Antarctic Basin is higher in CFC concentrations than that to the west in the Enderby Basin, due to the shorter distance of this water to the Adelie Land coast and Ross Sea sources. However, by 40°S, CFC concentrations in the bottom water of the Crozet Basin originating from the Weddell Sea are similar to those in the South Australia Basin. Independent observations, which show that bottom water undergoes elevated mixing between the Australia–Antarctic Basin and before entering the subtropics, are consistent with high CFC dilutions (3–14-fold) and a substantial concentration decrease (factor of 5) south to north of the Southeast Indian Ridge. CFC-bearing bottom waters with ages 30 years or more are transported into the subtropical South Indian Ocean by three western boundary currents, and highest concentrations are observed in the westernmost current. During WOCE, CFC-bearing bottom water reaches to about 301S in the Perth Basin, and to 201S in the Mascarene Basin. Comparing subtropical bottom water-CFC concentrations with those of the South Pacific and Atlantic oceans, at comparable latitudes, Indian Ocean bottom water- CFC concentrations are lower, consistent with its high dissipation rates from tidal mixing and current fluctuations as shown elsewhere. Thus, the generally high dilutions and low CFC concentrations in bottom water of the Indian Ocean are due to distance to the water mass source regions and the relative effectiveness of mixing. While it is not surprising that at thermocline, intermediate, and bottom levels, the significant ventilation sources on decadal time scales are all from the south, the CFCs show how local sources and mixing within the ocean affect the ventilation.

Title: Re: Antarctic Methane Concentrations
Post by: SteveMDFP on June 17, 2013, 12:14:43 PM
...  where the very cold temperatures would slow the chemical reduction of the methane, thus allowing it to accumulate in the high concentrations indicated in the first image.


A tiny, persnickety correction.  Methane is oxidized by hydroxyl radicals, not reduced.  The radicals are formed from sunlight and water vapor.  Methane in the atmosphere in polar regions tends to hit maximum in the dead of winter, due to absence of sunlight, and perhaps also colder temps slowing the chemical reaction.  This is a bit counter-intuitive, since release of methane from thawing permafrost and warming waters surely is at a maximum in the summer melt time.

But this is a small matter.  AbruptSLR's contributions to this forum are exceptional, extraordinary, and a bit intimidating in both quantity and sophistication. 
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 17, 2013, 11:35:30 PM
Bruce,

You are right that in my post #27 the sources of the AABW is further to the east as I believe that the image indicates two sources (from Adelie Land and the Ross Sea).  What I was thinking was that the fresh meltwater from the Moscow University Ice Shelf (and a little from Totten) is probably reducing the AABW production from Adelie Land; but I now see that the fresh meltwater from the Getz Ice Shelf maybe reducing the AABW from the Ross Sea (and the reduction of both sources of AABW would then result in seafloor warming near the Kerguelen Plateau.  However, I have to admit that as the methane concentration is located over the Antarctic mainland that methane hydrate could be decomposing due to seafloor warming from any location of reduced AABW (including the Weddell Sea or the Cape Darnley polynya); it is just that Purkey and Johnson 2013 show the greatest warming near the Kerguelen Plateau.  See various images for orientation and the following summaries related to AABW production from Adelie Land and the Cape Darnely polynya.


Antarctic Bottom Water from the Adélie and George V Land coast, East Antarctica (140–149°E)
By G. D. Williams; S. Aoki; S. S. Jacobs, S. R. Rintoul, T. Tamura, N. L. Bindoff
Article first published online: 30 APR 2010
DOI: 10.1029/2009JC005812
We report on observations of dense shelf water overflows and Antarctic Bottom Water (AABW) formation along the continental margin of the Adélie and George V Land coast between 140°E and 149°E. Vertical sections and bottom layer water mass properties sampled during two RVIB Nathaniel B Palmer hydrographic surveys (NBP00–08, December 2000/January 2001 and NBP04–08, October 2004) describe the spreading of cold, dense shelf water on the continental slope and rise from two independent source regions. The primary source region is the Adélie Depression, exporting high-salinity dense shelf water through the Adélie Sill at 143°E. An additional eastern source region of lower-salinity dense shelf water from the Mertz Depression is identified for the first time from bottom layer properties northwest of the Mertz Sill and Mertz Bank (146°E–148°E) that extend as far as the Buffon Channel (144.75°E) in summer. Regional analysis of satellite-derived ice production estimates over the entire region from 1992 to 2005 suggests that up to 40% of the total ice production for the region occurs over the Mertz Depression and therefore this area is likely to make a significant contribution to the total dense shelf water export. Concurrent time series from bottom-mounted Microcats and ADCP instruments from the Mertz Polynya Experiment (April 1998 to May 1999) near the Adélie Sill and on the upper continental slope (1150 m) and lower continental rise (3250 m) to the north describe the seasonal variability in downslope events and their interaction with the ambient water masses. The critical density for shelf water to produce AABW is examined and found to be 27.85 kg m−3 from the Adélie Depression and as low as 27.80 kg m−3 from the Mertz Depression. This study suggests previous dense shelf water export estimates based on the flow through the Adélie Sill alone are conservative and that other regions around East Antarctica with similar ice production to the Mertz Depression could be contributing to the total AABW in the Australian-Antarctic Basin.


Antarctic Bottom Water production by intense sea-ice formation in the Cape Darnley polynya
by: Kay I. Ohshima, Yasushi Fukamachi, Guy D. Williams, Sohey Nihashi, Fabien Roquet, Yujiro Kitade, Takeshi Tamura, Daisuke Hirano, Laura Herraiz-Borreguero, Iain Field, Mark Hindell, Shigeru Aoki & Masaaki Wakatsuchi
Nature Geoscience, Volume:6, Pages:235–240 (2013), doi:10.1038/ngeo1738
Abstract:
The formation of Antarctic Bottom Water—the cold, dense water that occupies the abyssal layer of the global ocean—is a key process in global ocean circulation. This water mass is formed as dense shelf water sinks to depth. Three regions around Antarctica where this process takes place have been previously documented. The presence of another source has been identified in hydrographic and tracer data, although the site of formation is not well constrained. Here we document the formation of dense shelf water in the Cape Darnley polynya (65°–69° E) and its subsequent transformation into bottom water using data from moorings and instrumented elephant seals (Mirounga leonina). Unlike the previously identified sources of Antarctic Bottom Water, which require the presence of an ice shelf or a large storage volume, bottom water production at the Cape Darnley polynya is driven primarily by the flux of salt released by sea-ice formation. We estimate that about 0.3–0.7×106 m3 s−1 of dense shelf water produced by the Cape Darnley polynya is transformed into Antarctic Bottom Water. The transformation of this water mass, which we term Cape Darnley Bottom Water, accounts for 6–13% of the circumpolar total.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 17, 2013, 11:49:31 PM
SteveMDFP,

Thank you for the correction, about oxidation, and also the kind words.  I do what I can in the little spare time that I have.  However, I will note that we are just beginning the Austral Winter now and according to the attached image from NOAA for June 16, 2013 at 525mb (which is typical of other similar altitudes) the concentration over the Antarctic mainland is now decreasing from what it has been from January 2013 up until a couple of weeks ago.  This implies to me that the source of methane is decreasing now.

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 18, 2013, 12:30:46 AM
Bruce,

I thought that you might like to look at the attached pdf about the Cape Darnely polynya being the second greatest source of AABW production after the Ross Sea area.

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: Bruce Steele on June 18, 2013, 03:37:15 AM
ASLR,  The polynya is new to me but that just shows my rather meager knowledge. Do you know of papers that describe fresh water influence on frazil ice production. Salinity is important to it's production and it would be interesting to see how freshening of the surface waters at the "great polynyas" has changed over the last few decades and maybe make some projections of further freshening on frazil ice production . Is this process or mixing with fresh water after the saline cold water is ejected from the surface the primary reason for the slowdown in bottom water formation?
http://onlinelibrary.wiley.com/doi/10.1029/93JC01905/abstract (http://onlinelibrary.wiley.com/doi/10.1029/93JC01905/abstract)

I will do some more research on my own and thanks for giving me a much better idea about how the Southern oceans work.
Title: Re: Antarctic Methane Concentrations
Post by: Bruce Steele on June 18, 2013, 04:48:52 PM
ASLR, this paper was in the references of the PDF you linked. It shows a strengthening of the Ross Sea polynya. I think the processes responsible for the slowdown  in bottom water formation and the reasons for it's warming are important to better understand if they are contributing to methane increases. I have been interested in how the slowdown changes ventilation of the deep oceans because shoaling of the hypoxic boundary has large influences on biology.

http://rkwok.jpl.nasa.gov/publications/Drucker.2011.GRL.pdf (http://rkwok.jpl.nasa.gov/publications/Drucker.2011.GRL.pdf)
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 18, 2013, 07:09:33 PM
Bruce,

With the caveat that I am an engineer and not a scientist; it is clear that the various factors that affect AABW production are more complex that my previously stated rule of thumb that generally more ice shelf meltwater reduces AABW; as you correctly point-out that in certain situations and ice shelf / ocean interactions AABW production could be increased (say if the geometry of the associated ice shelf changes by calving in interaction with bathemytry in a way that helps to  carry the AABW away via a deep channel/trough to the deep ocean, etc.

The attached two images are from:

Modelling Amery Ice Shelf/Ocean Interaction
by:Ben Galton-Fenzi
bkgalton@utas.edu.au
Antarctic Climate and Ecosystems CRC, Hobart, Australia
Simon Marsland(CSIRO), John Hunter (ACE CRC),
Richard Coleman (UTas)
WAIS/FRISP meeting: 27 Sept 2009, Pack Forest

The first attached image shows the ice shelf - ocean interaction including tidal action, advection, ice shelf water (ISW), frazil ice production, marine ice accretion and the influence of frazil ice on turbulent kinetic energy (TKE) which affect current mixing/stratification/circulation and thus can reduce AABW production as indicated in both the second image and in the following quote from Galton-Fenzi 2009:
"1. Frazil destabilises cool ISW plume, enhancing mixing with waters that melt base.
2. Frazil enhances the basal accretion of marine ice."

The influence of the frazil ice is also discussed in the following source:


"Observations of thermohaline convection adjacent to Brunt Ice ShelfBy: Ilker Fer , Keith Makinson and Keith Nicholls
Our observations provide direct evidence for enhanced dissipation rates associated with the conditional thermohaline convection mechanism proposed by Foldvik and Kvinge (1974). The ice crystal formation at depth and its ascent to the surface will influence the local sea ice budget and contribute to underwater ice production. Upwelling of the water associated with the convection might supply nutrients from the bottom layer toward the euphotic zone and enhance the primary production. The formation of ice crystals in suspension is probably a characteristic feature of the ice shelves producing ISW in the Southern Ocean and constitute an additional source of TKE production which might increase mixing substantially with consequences for the regional stratification and circulation."

Again, I agree that predicting the actual affect on AABW production is complex and requires the use of a computer model; but on average I believe that this information (especially the second figure) supports the rule of thumb that without ISW and the ice shelf - ocean interaction the AABW production would be higher (in general).

Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 20, 2013, 07:28:41 PM
I provide this post to emphasize the importance of the atmospheric methane concentration currently measured over Antarctica.  In this regard, the following extract comes from:

Atmospheric science: Tug of war on the jet stream,
by: Judith Perlwitz, Nature Climate Change Volume:1, pp:29–31 (2011) doi:10.1038/nclimate1065

http://www.nature.com/nclimate/journal/v1/n1/full/nclimate1065.html?WT.ec_id=NCLIMATE-201104 (http://www.nature.com/nclimate/journal/v1/n1/full/nclimate1065.html?WT.ec_id=NCLIMATE-201104)

"Recovery of the ozone hole and increasing greenhouse-gas concentrations have opposite effects on the jet stream. New model experiments indicate that they will cancel each other out over coming decades, leaving storm tracks at a stand still.
Over about the past 30 years, depletion of the ozone layer over Antarctica has had a greater effect on climate in the Southern Hemisphere than rising greenhouse-gas concentrations, causing a polewards shift of wind and precipitation patterns. Since about 2000, the so-called ozone hole has stopped enlarging and it is expected to close completely sometime after the middle of the century, in response to a ban on the production and use of ozone-depleting substances under the Montreal Protocol. This raises the question of whether wind and precipitation patterns will revert to their pre-ozone-hole conditions as the ozone layer recovers. Two new studies — one by Polvani and colleagues1 in Geophysical Research Letters and the other by McLandress and colleagues2 in Journal of Climate — show that as the ozone hole closes, increasing greenhouse-gas concentrations will counter the effects of ozone recovery, preventing atmospheric circulation from returning to 'normal'."
The  caption for the first attached image is:
"The locations of the westerly jet stream and the southern boundary of the Hadley cell, along with the storm tracks and subtropical dry zones associated with them, are affected by increasing greenhouse-gas concentrations and the recovery of the Antarctic ozone hole. Ozone-hole recovery causes them to shift towards the Equator (blue arrow) and increasing greenhouse-gas concentrations drive them towards the South Pole (red arrow). Polvani et al. and McLandress et al. explored the impact of these two anthropogenic climate forcings on atmospheric circulation and hydrological features over the twenty-first century using climate models. Both studies found that the location of circulation and precipitation patterns will not change during Southern Hemisphere summertime because the two forcings will cancel each other out."
The second attached image shows the relationship of the Hadley, Ferrel and the Polar, atmospheric cells.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 21, 2013, 12:53:50 AM
While I did not state it in my last post, as the GHG concentration over the South Pole increases, the Westerlies (and the Antarctic Polar Jet Stream) migrate southward.

Also, I thought the attached image from April 2013 would help to locate the position of the concentrated atmospheric methane over Antarctica.
Title: Re: Antarctic Methane Concentrations
Post by: Bruce Steele on June 21, 2013, 01:35:08 AM
ASLR, "the AABW overflows entrain on average about an equal amount of warmer( >0c ) Circumpolar Deep Water." Orsi et al 1999 . So the largest driver of  the slowdown of AABW is probably the warmer Upper Circumpolar Deep Water that it is coming in contact with and mixing with AABW on it's descent. I know the CDW  is warming but are there projections for the rate of warming to increase? I keep thinking the heat that has been documented entering depths ( to 2000 meters ) must take awhile to feed into the CDW. It just seems like the 900 lb. Gorilla.   
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 21, 2013, 02:45:36 AM
Bruce,

I agree that both the increase in the temperature of the CDW and the increase in the volume of the CDW (note that according to Purkey & Johnson as the AABW volume is decreasing the CDW volume is increasing) will be critical for ice mass (VAF) from Antarctica.  While I do not have time to dig-up specific trends:

(a) the first attached image (from RealClimate) shows how during the El Nino hiatus period more heat content has been going into the deep ocean and I have seen projections that upto half of this deep ocean heat content will telecommunicate into the Southern Ocean.
and (b) the second image shows the trend of increasingly positive Southern Annular Mode (SAM) that is increasing the wind velocity around the Southern Ocean and thus both increasing the velocity of the ACC and more importantly increasing the volume of warm CDW near the ocean-ice interface around Antarctica.  Also, note that as the ozone hole is shrinking and the ozone hole is more effective in inducing positive values of SAM than is GHG, one might expect that the values of SAM should be becoming less positive; and I suspect the fact that the values of SAM are still trending toward more positive values, may indicate how effective the high atmospheric methane concentrations over Antarctica are at making values of SAM more positive.  See also the write-up below regarding the second image:

"The Southern Annular Mode (SAM), which is defined by changes in the westerly winds that are driven by temperature contrasts between the tropics and southern polar areas. The annular modes generally take a circular pattern (‘annular’ means ring-shaped) and see-saw between positive and negative phases for weeks or months. In the SAM’s positive mode, the ring is stronger and further south, inhibiting Antarctic air outbreaks. In the negative mode, a weaker, more variable vortex allows Antarctic air to spill north more easily.
The Southern Annular Mode has steadily trended positive in recent decades. Computer models indicate this trend is related to ozone depletion above Antarctica and increases in greenhouse gases." (the attached second image is courtesy Jianping Li, China Institute for Atmospheric Physics.)
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 21, 2013, 04:48:51 PM
I have discussed the upwelling of warm CDW in many different threads, but I will continue this discussion in this thread because I believe that some of the methane hydrate decomposition is occurring along the Queen Maud Coast where Purkey & Johnson have identified a current of warm CDW has recently entered the eastern side of the Weddell Gyre (coming from the north), from which location it then travels westward along the Queen Maud Coast (and from there I have speculated that some of this current then enters the Filchner Trough where it then continues on to accelerate basal ice melting from the FRIS, particularly near the grounding line).  In this regards, the first attached image comes from the following website, together with the associated summary statement below:
http://dimes.ucsd.edu/ (http://dimes.ucsd.edu/)
"Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean, DIMES, is a US/UK field program aimed at measuring diapycnal and isopycnal mixing in the Southern Ocean, along the tilting isopycnals of the Antarctic Circumpolar Current.
The Meridional Overturning Circulation (MOC) of the ocean is a critical regulator of the Earth's climate processes. Climate models are highly sensitive to the representation of mixing processes in the southern limb of the MOC, within the Southern Ocean, although the lack of extensive in situ observations of Southern Ocean mixing processes has made evaluation of mixing somewhat difficult. Theories and models of the Southern Ocean circulation have been built on the premise of adiabatic flow in the ocean interior, with diabatic processes confined to the upper-ocean mixed layer. Interior diapycnal mixing has often been assumed to be small, but a few recent studies have suggested that diapycnal mixing might be large in some locations, particularly over rough bathymetry. Depending on its extent, this interior diapycnal mixing could significantly affect the overall energetics and property balances for the Southern Ocean and in turn for the global ocean. The goals of DIMES are to obtain measurements that will help us quantify both along-isopycnal eddy-driven mixing and cross-isopycnal interior mixing.
Schematic representation of Southern Ocean meridional overturning circulation. The isopycnal upwelling of Upper and Lower Circumpolar Deep Water (UCDW and LCDW, with sources in the North Atlantic) is supported by mean geostrophic mass fluxes below the level of topographic obstacles to the ACC and by mesoscale eddy-driven mass fluxes at mid-depth. The upwelled water changes density through air-sea-ice interaction. It then returns northward in the wind-driven Ekman layer to form Antarctic Intermediate Water (AAIW), and as Antarctic Bottom Water (AABW) in mean geostrophic flows. The magnitude of interior diapycnal mixing and the rate of along-isopycnal mixing are open for investigation and are the DIMES objectives."
The second attached figure provides an alternate representation of this upwelling of the warm CDW and clarifying that much (but not all) of this upwelling system is driving by the circumpolar winds that are partially sustained by the high atmospheric methane over Antarctica.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on June 21, 2013, 05:47:24 PM
To many the following comment goes without saying, but at the risk of stating the obvious, I would like to note the following with regard to the second attached image for my reply #42 at 2:45am on June 21, 2013, of the trend of the Southern Annular Mode, SAM: 
As SAM is an oscillation it fuctuates about the indicated nonlinear trend line (the trend line is nonlinear because of the nonlinear influence of both the ozone hole and the GHG on promoting a positive SAM trend); but also the strength and latitude of the circumpolar winds (implied by the SAM index value) is strongly influence by interactions with the ESNO index. For example the highest (most positive) SAM value shown is for the 1997-1998 season which is as the period of the last strong El Nino event when much of the damage was done to the ice shelves in the ASE by warm CDW (caused by upwelling), and which also temporarily accelerated ice mass loss (VAF) from both PIG and TG.  Thus when the current El Nino hiatus period ends, we may well experience the return of exceptionally positive SAM values (particularly if continued venting of methane into the Antarctic atmosphere continues to drive up the SAM trend line).
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on June 24, 2013, 08:16:10 PM
I thought a glimpse at the recent readings of three elements in the Antarctic GHG and climate changes to come might be of interest. What follows first is the CH4 levels for June 22, 2013 am at 469 mb, with a possible high concentration of 2142 ppbv.

Second are the CO2 levels for June 22 2013 am at 469 mb and possibly up to 423.6 ppm.

The final images are the Antarctic surface temperature anomalies for June 22, 2013
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on June 24, 2013, 08:18:19 PM
Now the CO2 readings, from the same perspective. The highest possible reading is 423.6 ppm.
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on June 24, 2013, 08:20:45 PM
The final images are the Antarctic surface temperature anomalies for June 22, 2013.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 03, 2013, 04:54:18 PM
In the way of a status report, the attached image (at 585 mb) indicates that the anomolously high atmospheric methane concentrations over Antarctica are continuing (although at concentrations that are a little bit lower than during the immediately past Austal Fall).
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 11, 2013, 07:54:25 PM
I would like to complement both Omar Cabrera and A4R on their excellent 3D methane tracker at the new website:

http://methanetracker.org (http://methanetracker.org)

Omar Cabrera's reviews of the new website can be found at the You Tube links:

Video 1: Unified Methane Layers from MethaneTracker.org (1 of 2) (http://www.youtube.com/watch?v=E1OluDXNXJ4#ws)
Video 2: Unified Methane Layers from MethaneTracker.org (2 of 2) (http://www.youtube.com/watch?v=j_xaifA5-wI#ws)

In the second You Tube video, Omar repeats his doubts that the recent high Antarctic atmospheric methane concentrations have their origins in marine methane hydrates, and expresses his believe that Albert Kallio's theory that heat from the asthenosphere may be decomposing methane hydrate beneath the EAIS, thus allowing this postulated release of methane to seep through the ice sheet directly into the atmosphere.

While I am very impressed by the 3D tool that Omar is creating at the methanetracker site; I respectfully, state my disagreement with Albert Kallio's theory, cited above.

It is my opinion that the Antarctic case is similar to that for the Arctic case (only shifted by 6 months to match the Austral seasons); where marine methane hydrate decomposition releases more methane as the seawater over the continental shelves warm-up by the end of summer (around February in the Antarctic), thereafter the atmospheric methane concentration increases due to the chemical reactions in the atmosphere as described below:

Antarctic atmospheric methane concentrations decrease from Austral Spring thru Summer, as the methane gets oxidized and converted to other gases.  Similarly, Antarctic atmospheric methane concentrations increase from Austral Fall thru Winter, as the cold temperatures limit chemical reactions between CO₂ and CH4.  The annual cycle is due to reactions with hydroxyl radicals, which is the dominant methane sink: The hydroxyl radical is produced in the atmosphere by sunlight, which explains the cycle. Hydroxyl oxidizes methane in a complicated network of reactions ending in CO2 and H₂O, as described at the following Wikipedia site:

http://en.wikipedia.org/wiki/Atmospheric_methane#Removal_proc (http://en.wikipedia.org/wiki/Atmospheric_methane#Removal_proc)

After gassing out from the Antarctic continental shelves, CH4 accumulates in the atmosphere during the Antarctic night but as the Sun returns to the Antarctic, UV + Hydroxil Radical convert atmospheric CH4 into CO2, H2O. See the following Wikipedia site:

 http://en.wikipedia.org/wiki/Hydroxyl_radical (http://en.wikipedia.org/wiki/Hydroxyl_radical)

In support of my position, I post the attached image from NOAA's website for 586mb on July 9th, 2013, showing that the Antarctic atmospheric methane concentration is now decreasing (it peaked in May); which makes sense if the cold slowed hydroxyl radicals are finally oxidizing the methane release from the oceans in the Austral Fall; while it makes no sense at all for the Albert Kallio theory based on heat from the asthenosphere, which theoretically should happen year round (not seasonally).  See also, my earlier posts in this thread on this topic.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 11, 2013, 08:42:17 PM
As a side note to my immediately preceeding post, Omar notes in his first video that methane emissions are currently being observed in desert areas, particularly after rainfall events.  While I am no expert on this topic; I observe that the increase in atmospheric carbon dioxide has lead to the recent observations of increased vegetation growth in deserts; and it may be possible that rainfall events in the deserts temporarily lead to a breakdown of the increase organic matter into methane, and once the rain has passed the breakdown of the organic matter would return to emitting carbon dioxide.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 11, 2013, 11:03:55 PM
I would also like to note that Omar states in his video that the winds are blowing the wrong way to accummulate methane in the upper Antarctic atmosphere (troposphere).  However, while I am not an expert, the attached image of the origins of Katabatic winds and how they blow outward from the surface of the Antarctic; implies to me that atmosphere from the Antarctic perimeter must be drawing into the upper Antarctic troposphere as indicated by the arrows in the attached figure.  In my opinion this provides an explanation of how the marine emissions of methane from hydrate decomposition could migrate over Antarctica where it could accumulate in the Austral Fall and early Winter.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 12, 2013, 04:33:26 PM
Not to be too assiduous on this topic but I thought that I would post the following additional arguements/evidence in favor of the marine hydrate source of Antarctic atmospheric methane as opposed to Albert Kallio's theory:

First, the following 2010 internet article cites a couple of examples of methane hydrate leakages from the Antarctic seafloor associated with local warming of the coastal waters of the Southern Ocean (this supports the seasonality of my theory):

"Argentine Geologist Finds Gas Venting Into Antarctic Ocean From Seafloor To Be 99% Methane - Nature:
Persistent bubbling is stirring the water's surface in the Erebus and Terror Gulf, a remote spot off the Antarctic Peninsula. When he saw the commotion in 2000, Argentinian geologist Rodolfo del Valle was intrigued — despite 38 years' experience in the region. There was a chance the gas contained methane, and when del Valle's team investigated the leak they discovered it to be 99% methane.

This is bad news. The gas is not only 25 times more powerful than carbon dioxide at heating the atmosphere; methane hydrates locked up in the Antarctic seabed and ice also contain vast amounts of carbon — overall, methane deposits contain about half of global carbon. With a recorded decline in Antarctic ice shelves, the long-term effect of deteriorating and melting ice could range from boosting global warming to helping trigger mass extinctions. Nature caught up with del Valle on the eve of his departure for the first on-the-ground study to quantify methane leakage in shallow waters and ice in the Gulf.


Q: Will you be investigating any direct consequences of methane leakage around the northern Antarctic peninsula?

A: The British Falkland Islands Dependencies Aerial Survey Expedition findings from the mid-1950s showed unusual numbers of crabeater seals dying in this area. Members of the expedition suggested that methane could be implicated. During the calving season, seals live and give birth on top of the frozen layer of sea, and dive for food through holes in the ice. One theory is that methane accumulates under the marine ice and escapes through cracks during low tides. The methane deposits located below the ice then expand. These emissions would be responsible for the massive death of seals: methane is usually accompanied by hydrogen sulphide, a toxic metabolite of methanogenic bacteria at the seabed. So we'll be looking at that in connection with the seal deaths."


Second, while the NOAA methane South Pole flask measurement are only reported to the end of January 2013 at the following website, I believe that when the rest of 2013 flask data is reported by NOAA that no unusual releases will be reported at the ground based readings; which would support my idea that the methane floats up over the ocean and is moved by upper tropospheric winds over the continent, thus bypassing the NOAA ground based flask readings:

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)]http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts


Third, as the continental crust is unusually thin in the West Antarctic and unusually thick in the East Antarctic if Albert Kallio's theory were true then would would expect to see higher atmospheric methane readings over the West Antarctic as compare to the East Antarctic, but this is the opposite of what is observed.  While by my theory the atmospheric heat telecommunicated from the Pacific Tropics to the West Antarctic atmosphere would make this air too warm to slow the OH oxidation of CH4; while the East Antarctic atmosphere temperature would be just right to match my assumptions.
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on July 12, 2013, 08:07:20 PM
Abrupt SLR,

I'll comment more later, but what might help all of us is if you can find sources that map the wind patterns in the Antarctic from the time that high concentration began to current date, to help us understand the high concentrations of Antarctic methane this winter.

I have not read the above thread, if you answered the question already, my apologies.

I hope you'll continue to explore methanetracker.org as it continues to help us build a picture of global methane concentration.

A4R
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 12, 2013, 10:15:32 PM
A4R,

I imagine that the resolution of identifying the source of the Antarctic methane will take some time, and combining the historical winds with the measured methane concentrations would be a major step forward on this matter.  Part of the problem with the wind is that it is different at different altitudes/elevations, and I am not sure that we can find the type of historical wind data that you need, but if you have the time, you might want to look through the data available at the following sites:

http://www.weather-forecast.com/maps/Antarctica (http://www.weather-forecast.com/maps/Antarctica)

http://ossfoundation.us/projects/environment/global-warming/projects/environment/global-warming/current-climate-conditions/storm-trends#section-2 (http://ossfoundation.us/projects/environment/global-warming/projects/environment/global-warming/current-climate-conditions/storm-trends#section-2)

https://amrc.ssec.wisc.edu/ (https://amrc.ssec.wisc.edu/)

http://pansy.eps.s.u-tokyo.ac.jp/ResearchTopics-e.html (http://pansy.eps.s.u-tokyo.ac.jp/ResearchTopics-e.html)


Regarding possible ocean sources for methane, it is possible that they are distributed all around much of the Antarctic coastline, as the attached image from Rignot et al 2013 implies that at least seasonally the coastal ocean water is at least warm enough to cause basal ice melting of the ice shelves all around Antarctica; which by extension implies that that ocean water was at least seasonally warm enough to decompose any methane hydrates near the seafloor.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 13, 2013, 04:42:13 PM
A4R,

A few more points that you should consider when evaluating how reasonable any theory (eg Albert Kallio's) is that proposes that methane leaks through thousands of meters of East Antarctic Ice Sheet directly into the atmosphere above, include:

- Kallio assumes that the heat decomposing the methane hydrate comes from below the crust; which would imply that at least many hundreds of meters of hydrate containing soil had been completely disassociated forming very large free gas zones in the bed soil beneath the relatively impermeable hydrate saturated topsoil (just do some Google searchers to see that soil saturated with hydrates is relatively impermeable to free gas).  This would be an extremely large volume of free gas the affect of which would be easily seen in the paleo-record of previous times that the EAIS began to retreat (or even melt totally), but no such record has been reported.

- Even if all of the methane hydrate in the soil was disassociated so that free gas from the bed soil was in direct contact with the underside of the EASI; you should realize that the methane hydrates are more stable than normal ice at these pressures; therefore, any amount of geotechnical heat sufficient to release the methane would cause a considerable amount of basal ice melting; which has not been reported yet, and again there is no paleo-record of any such massive about of EAIS basal melting occurring in the past.

- Lastly, you yourself (today) in the Arctic Sea Ice Blog note that only a relatively thin layer of Arctic Sea Ice is sufficient to trap free methane gas below it for at least months, no matter how fractured the sea ice might be.  Now, with thousands of meters of ice thickness in the EAIS there are no large factures in the ice sheet comparable to those in the Arctic Sea Ice, see the article below (that you already know about):

https://darchive.mblwhoilibrary.org/bitstream/handle/1912/4916/24-3_loose.pdf?sequence=1

Therefore, believe that Kallio's theory does not seem reasonable; and that the most likely source of the Antarctic atmospheric methane is from the marine environment.

Please keep up your great work on documenting methane releases, as I am certain that it is a growing problem (and the measured increase in Antarctic atmospheric methane is already sufficient to offset much of the ozone healing in Antarctica); nevertheless, I find Kallio's theory to be unacceptable from a physics point of view.

Best,
ASLR

Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 15, 2013, 02:09:15 AM
I thought that I would post the atmospheric methane readings for July 13, 2013 indicating that concentration of atmospheric methane over Antarctica is continuing to decrease, as one might expect for a coastal marine source of methane emissions.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 16, 2013, 02:08:39 AM
I thought that I would note that at least until February 2013 the atmospheric methane concentration from NOAA's South Pole station (see the first attached image); follows the general shape of the atmospheric methane concentration from NOAA's Mauna Loa station (which is roughly typical of the global average, see the second attached image).
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 16, 2013, 10:18:15 PM
A4R,

First, the following is another Antarctic Weather site that might have useful wind data for you:

http://www.antarctica.ac.uk/met/metlog/ (http://www.antarctica.ac.uk/met/metlog/)

Second, the attached image shows how the ozone hole forms a geopotential well in the atmosphere that can trap methane emitted from the ocean into the well over the continent.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 20, 2013, 01:13:40 AM
I thought that I should note that the attached figure shows that the atmospheric methane content is higher than last week.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 24, 2013, 02:41:53 PM
I do not have time to provide a reference, but I have read that as atmospheric humidity increases with global warming, the amount of high troposphere ice particles will increase, and that as there ice particles generally serve to reduce the rate of methane oxidation; this iimplies that with increasing global warming, the global warming potential, GWP, of the methane in the atmosphere over the Antarctic will increase.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 24, 2013, 04:53:12 PM
As a follow-up to my immediately prior post; I provide a copy of the following Internet article which state: (a) when methane is oxidized in the upper atmosphere, it creates water molecules that then contribute to the formation of ice crystals in the upper atmosphere; which in turn contribute to the increased formation of Noctilucent clouds (NLCs); and (b) NLCs are being observed with increasing frequency in the Antarctic Atmosphere.  Therefore, as this thread notes that methane is becoming increasingly concentrated in the Antarctic Atmosphere, and as ice crystals (particles) are also becoming more concentrated over Antarctica; and as the interaction of methane molecules and ice crystals (particles) increase the global warming potential, GWP, of methane; I believe that this constitutes as positive feedback mechanism that will contribute to accelerated ice mass loss from Antarctic as global warming continues:

http://science.nasa.gov/science-news/science-at-nasa/2013/07jun_nlcs/ (http://science.nasa.gov/science-news/science-at-nasa/2013/07jun_nlcs/)

"June 7, 2013:  Every summer, something strange and wonderful happens high above the north pole.  Ice crystals begin to cling to the smoky remains of meteors, forming electric-blue clouds with tendrils that ripple hypnotically against the sunset sky.  Noctilucent clouds—a.k.a. "NLCs"--are a delight for high-latitude sky watchers, and around the Arctic Circle their season of visibility is always eagerly anticipated.
News flash: This year, NLCs are getting an early start. NASA's AIM spacecraft, which is orbiting Earth on a mission to study noctilucent clouds, started seeing them on May 13th.
"The 2013 season is remarkable because it started in the northern hemisphere a week earlier than any other season that AIM has observed," reports Cora Randall of the Laboratory for Atmospheric and Space Physics at the University of Colorado. "This is quite possibly earlier than ever before."

The early start is extra-puzzling because of the solar cycle.  Researchers have long known that NLCs tend to peak during solar minimum and bottom-out during solar maximum—a fairly strong anti-correlation.  "If anything, we would have expected a later start this year because the solar cycle is near its maximum," Randall says. "So much for expectations."
For sky watchers, this means it's time to pay attention to the sunset sky, where NLCs are most often seen.  An early start could herald brighter clouds and wider visibility than ever before.
Noctilucent clouds were first noticed in the mid-19th century after the eruption of super-volcano Krakatoa. Volcanic ash spread through the atmosphere, painting vivid sunsets that mesmerized observers all around the world.  That was when the NLCs appeared. At first people thought they must be some side-effect of the volcano, but long after Krakatoa's ash settled the noctilucent clouds remained.
"They've been with us ever since," says Randall.  "Not only that, they are spreading."
When AIM was launched in 2007, the underlying cause of NLCs was still unknown. Researchers knew they formed 83 km above Earth's surface where the atmosphere meets the vacuum of space--but that's about all.  AIM quickly filled in the gaps.
"It turns out that meteoroids play an important role in the formation of NLCs," explains Hampton University Professor James Russell, the principal investigator of AIM. "Specks of debris from disintegrating meteors act as nucleating points where water molecules can gather and crystallize."
NLCs appear during summer because that is when water molecules are wafted up from the lower atmosphere to mix with the "meteor smoke." That is also the time when the upper atmosphere is ironically coldest.
Back in the 19th century, NLCs were confined to high latitudes.  You had to go to Alaska or Scandinavia to see them.  In recent years, however, they have been sighted as far south as Utah, Colorado, and Nebraska. Some researchers believe that the spread of NLCs is a sign of climate change.
One of the greenhouse gases that has become more abundant in Earth's atmosphere since the 19th century is methane.  "When methane makes its way into the upper atmosphere, it is oxidized by a complex series of reactions to form water vapor," says Russell. "This extra water vapor is then available to grow ice crystals for NLCs."
The early start of the 2013 season appears to be caused by a change in atmospheric “teleconnections.”
“Half-a-world away from where the northern NLCs are forming, strong winds in the southern stratosphere are altering global circulation patterns,” explains Randall. "This year more water vapor is being pushed into the high atmosphere where NLCs love to form, and the air there is getting colder."
"All of this has come as an interesting surprise for us," notes Russell.  "When we launched AIM, our interest was in the clouds themselves.  But now NLCs are teaching us about connections between different layers of the atmosphere that operate over great distances. Our ability to study these connections will surely lead to new understanding about how our atmosphere works.""
Title: Re: Antarctic Methane Concentrations
Post by: prokaryotes on July 27, 2013, 01:36:34 AM
I collected some data and assembled some input and theories about methane origin  (also from this thread)

East Antarctic Methane Emissions
http://climatestate.com/magazine/2013/07/east-antarctic-methane-emissions/ (http://climatestate.com/magazine/2013/07/east-antarctic-methane-emissions/)
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 27, 2013, 02:07:03 AM
Prokaryotes,

Thank you for the quote; however, since I made that quote; I now believe that not only may methane be venting from marine methane hydrates near the Kerguelen Plateau, but additionally from many other Antarctic continental shelves (all around the continent) where warm CDW is intruding on to the continental shelves (particularly in to troughs on the continental shelves).  Such dispersed methane emissions would be difficult to see at sea level by satellite; but when accumulated higher up (from about 400 mb to 600 mb) over the East Antarctic by the concave shape of the atmospheric geopotential height caused by the ozone hole and local GHG (including the methane) over Antarctica.  As I have noted in prior posts, I believe that the cold temperatures and the increasing formation of ice crystals in the atmosphere high over Antarctica reduces the rate of oxidation of the methane, thus allowing lower concentrations to accumulate, just as they do in the Arctic.

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: prokaryotes on July 27, 2013, 02:11:56 AM
Ok, i updated the quote from you in above linked article. Thanks for your input AbruptSLR.
Title: Re: Antarctic Methane Concentrations
Post by: prokaryotes on July 27, 2013, 01:34:47 PM
Are these methane readings through perforations in the rocky to ice layer on higher elevations? Can these gas molecules penetrate-vent through the ice sheet on higher elevation or through perforations - are there any surface layer to bedrock layer type of features in these area recorded?

Update
Added commentary by Leonid Yurganov and AbruptSLR's Katabatic winds image to the article (linked above).

Re Katabatic winds:
Quote
In a few regions of continental Antarctica the snow is scoured away by the force of the katabatic winds, leading to "dry valleys" (or "Antarctic oasis") such as the McMurdo Dry Valleys. Since the katabatic winds are descending, they tend to have a low relative humidity which desiccates the region. Other regions may have a similar but lesser effect, leading to "blue ice" areas where the snow is removed and the surface ice evaporates, but is replenished by glacier flow from upstream.
http://en.wikipedia.org/wiki/Katabatic_wind (http://en.wikipedia.org/wiki/Katabatic_wind)

I have read that as atmospheric humidity increases with global warming, the amount of high troposphere ice particles will increase, and that as there ice particles generally serve to reduce the rate of methane oxidation; this iimplies that with increasing global warming, the global warming potential, GWP, of the methane in the atmosphere over the Antarctic will increase.

Relevant
Quote
There are two driving forces behind the change in stratospheric moisture. Increasing emissions of methane are transformed into water in the stratosphere by chemical reactions. This can account for about a third of the observed increase in moisture there.

In addition, there is a greater transport of water from the lower atmosphere, which happens for several reasons. First of all, more water may be available in the lower atmosphere to be carried up. Warmer air holds more water vapor than colder air, so global warming will make the lower atmosphere wetter. Another possibility is that air is carried up more rapidly into the stratosphere. Climate models indicate that greenhouse gases such as carbon dioxide and methane may enhance the transport of air from the lower atmosphere up into the stratosphere. Additionally, the coldest temperature through which the air passes could change, which would alter the amount of water that freezes out along the way.
http://www.giss.nasa.gov/research/briefs/shindell_05/ (http://www.giss.nasa.gov/research/briefs/shindell_05/)

Ofc the pole is a special spot though it might differ there.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 27, 2013, 05:58:50 PM
Prokaryotes,

I will provide the following responses in the limited time available to me:

First, ice is both brittle (so it cracks) and viscous (so it flows like honey); thus as glaciers flow towards the ocean they deform, which generates internal heat, which causes internal melting, which can create some volumes which if created in sufficiently volumes (due to sufficiently high ice velocities) will rain down through microcracks to add to the volume of the system of subglacial basal melt water hydrological system of subglacial lakes, streams, swamps, etc.  Therefore, the hydrostatic pressures with the subglacial hydrological systems are about equal to pressures associated with the weight of the height of the ice in that particular area (otherwise the weight of the ice above say a subglacial lake would squeeze the subglacial water out of the subglacial lake (which can occur when the seal is broke linking the subglacial water to the ocean).  As Sidd notes subglacial melt water can and regularly does flow uphill (say up out of the BSB) just like water inside of a steel pipe can and does flow up to the top of a multi-story building, because the ice above the subglacial melt water forms a seal (including the seal provided by the internal melt water caused by internal friction that is filling any microcracks in the glaciers caused by internal deformations.  Now if the ice forms a seal to the water it also forms a seal for most any methane gas that might be trying to vent upwards from the East Antarctic crust; and more importantly, methane hydrates are more stable than ice under pressure; thus any methane gas trying to flow upwards through water filled microcracks in the glacier would form methane hydrates, thus effectively sealing the microcracks.  Therefore, as I told A4R and now I am telling you, I absolutely do not believe that the atmospheric methane measured over East Antarctica  is venting up through the several kilometer thick semi-viscous EAIS.

Second, as you have noted methane hydrates can form beneath Antarctic glaciers (due to biological processes); and as in the past 10,000 to 30,000 years glaciers use to be resting on almost all of the Antarctic continental shelves but has now retreated; therefore, you must believe that there are substantial quantities of methane hydrates in the sediments of the Antarctic continental shelves (just like you must believe is the case for the East Siberian Arctic Shelf, ESAS, in the Arctic).  Thus, it is much more logical to believe that as the warm CDW flows increasingly onto the Antarctic continental shelves, troughs and submerged plateaus, that the warm CDW would destabilize sufficient amounts of the methane hydrates in the seafloor sediment to cause local slope stability failures (submerged landslides) along the sides of the troughs, plateaus, and shelf/slope breaks, that would release sufficient quantities of methane gas that they could float to the surface before being re-absorbed by the ocean water (which is not saturated with methane), as is postulated by the Clathrate Gun Hypothesis (see my other posts on this topic, or Google it). 

Third, once vented from the numerous small subsea landsides around the perimeter of the Antarctia seafloor, I believe that this methane floats up onto the shoulder of the atmospheric geopotential height concave topology, where winds circulate towards the center of East Antarctica, where during the austral fall and winter months the lack of sunlight reduces the rate of methane oxidation sufficiently for significant quantities of methane to accumulate (as is the case in the Arctic for the Fall and Winter).

Fourth, you point out that Katabatic winds flow down from the center of East Antarctica and out towards the coast, and that the Katabatic wind is dry (implying that you think that the wind blows out from the center of Antarctica and thus the wind could never carry methane from the perimeter of Antarctica towards the center; which is incorrect, as I have stated above that the methane emissions around the perimeter would float up first and then be drawn into the center of Antarctica by the same vacuum caused by the air flowing down from the center of Antarctica that creates the Katabatic winds in the first place (see the figure in my post above in this thread).  The fact that the Katabatic wind is dry is because any moisture in the upper atmosphere over central Antarctica is so cold that it transformed into ice crystals (that serve to protect the methane from rapid oxidation), so that when the Katabatic wind decends they are carrying ice crystals and snow rather than water.

The complex nature of the Antarctic is why this is a playground for denialist to say anything that they want, without risk of being exposed.  Therefore, it is important to get the true story straight, because in any non-linear system small initial differences can result in large eventual differences.

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: prokaryotes on July 30, 2013, 01:16:38 PM
Identification and control of subglacial water networks under Dome A, Antarctica

Quote
“Subglacial water in continental Antarctica forms by melting of basal ice due to geothermal or frictional heating. The water system in the Gamburtsev Subglacial Mountains reoccupies a system of alpine overdeepenings created by valley glaciers in the early growth phase of the East Antarctic Ice Sheet. The networks follow valley floors either uphill or downhill depending on the gradient of the ice sheet surface. In cases where the networks follow valley floors uphill they terminate in or near plumes of freeze-on ice, indicating source to sink transport within the basal hydrologic system. Because the ice surface determines drainage direction within the bed-constrained network, the system is bed-routed but surface-directed.”
http://adsabs.harvard.edu/abs/2013JGRF..118..140W (http://adsabs.harvard.edu/abs/2013JGRF..118..140W)

Not sure if i understand this correctly but maybe basal melt and following uphill drainage is transporting melted methane hydrates to the surface?
Title: Re: Antarctic Methane Concentrations
Post by: Apocalypse4Real on July 30, 2013, 04:21:35 PM
AbruptSLR,

Thanks for all your work on Antarctic methane and the compilation of sources.

Another new tool has been added to methanetracker.org, that is the breakdown of CH$ concentrations into three display layers:

1750-1850 ppb
1850-1950 ppb
1950+ ppb

This function is retroactive to January 2013, similar to the macro function.

Also, the reporting has been updated.

A4R
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 30, 2013, 11:02:35 PM
A4R,

Thanks for your untiring work to bring the hazards of methane emissions to a broader audience. 

Separately, I provide the following phase diagram for natural gas hydrates; which indicates that even if pure methane were being introduced into the melt water in essentially any portion of the AIS subglacial hydrological system; the pressure within such basal melt water would most likely  (almost certainly) be sufficiently high to cause such methane gas to recombine with the melt water in order to form natural gas hydrates before the gas could reach the atmosphere.  As a side note the Gas Gravity is the weight of mole of the natural gas in question divided by the weight of a mole of air.
Title: Re: Antarctic Methane Concentrations
Post by: no1der on July 31, 2013, 05:13:51 PM
The region of apparently elevated CH4 concentrations over East Antarctica is coincident with high elevation and coldest temperatures.

A very similar pattern is observed over the higher elevations of N. Greenland around 2-27-13.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1333.photobucket.com%2Falbums%2Fw624%2Fkyanite2%2FGreenlandsummitmethane2_27_13_zps81d3af91.png&hash=cde7eaff696c86c3aa2cc3dbbde3da03)

Before considering increasingly unlikely emission and/or collection scenarios, can it be verified that we aren't looking at an instrumental artifact?
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 31, 2013, 06:27:21 PM
no1der,

A4R is probably better qualified to respond about the validity of the instrument readings; however, at the NOAA satellite readings have been widely reviewed it is my opinion that due to the very cold/dark conditions in the atmosphere over East Antarctica during the austral winter, that the continuing measurement of methane around 500 mb altitude, is more of an indication that the rate of methane oxidation and dispersal is so low that we are seeing much the same methane molecules for a long time, rather than seeing large emissions from some unlikely emission scenario.  Again, we should be aware that the conditions in the atmosphere over Antarctica are more favorable for concentrating methane during the austral winter than is the case for the Arctic during the winter, and we should note be unduly swayed by prior Arctic experience when evaluating the measured Antarctic situation.

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: no1der on July 31, 2013, 08:07:48 PM
I raise the question about instrumental artifact because elevated apparent CH4 concentrations can be seen over interior N. Greenland in early to mid Jan, and late Feb to early Mar 2013. Looking at the Summit, GL temperature history, these were the coldest periods of the winter, with weekly mean temperatures in the -40's F and average minima in the -50's F. Warmer intervals seem not to show the apparent methane anomalies. (Eyeballing methane tracker.org and http://www.wunderground.com/history/wmo/04416/2013/2/27/WeeklyHistory.html (http://www.wunderground.com/history/wmo/04416/2013/2/27/WeeklyHistory.html), absent a rigorous work-up). One could propose a T-dependent mechanism but before doing so it might be better to rule out some sort of instrumental or measurement artifact.

Noting that apparent methane anomalies are showing over Greenland at high elevation on the ice sheet and coincident with surface temperatures of ca. -50F or less, one might fairly wonder if the remarkably well-defined and persistent periphery of the apparent Antarctic methane anomalies does not circumscribe similar conditions.

Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 31, 2013, 08:49:42 PM
no1der,

Certainly, at high altitudes over Greenland in the coldest parts of winter the chemical oxidation of methane is also slowed down, which should also allow methane to accumulate until a changing weather pattern blows the methane away.  Typically, it is colder still in Antarctica (in the austral winter) and the weather is also more stable; which might explain why the methane concentrations over East Antarctica appear to be both bigger and longer lasting than over Greenland (assuming that the satellite instrument is working well).

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2013, 11:44:52 PM
The following reference gives an idea of the complexities of determining the lifetime of methane based on atmospheric chemistry (the weblink leads to a free pdf of the paper):

http://www.atmos-chem-phys.net/13/5277/2013/acp-13-5277-2013.pdf (http://www.atmos-chem-phys.net/13/5277/2013/acp-13-5277-2013.pdf)

Naik, V., A. Voulgarakis, A.M. Fiore, L.W. Horowitz, J.-F. Lamarque, M. Lin, M.J. Prather, P.J. Young, D. Bergmann, P.J. Cameron-Smith, I. Cionni, W.J. Collins, S.B. Dalsøren, R. Doherty, V. Eyring, G. Faluvegi, G.A. Folberth, B. Josse, Y.H. Lee, I.A. MacKenzie, T. Nagashima, T.P.C. van Noije, D.A. Plummer, M. Righi, S.T. Rumbold, R. Skeie, D.T. Shindell, D.S. Stevenson, S. Strode, K. Sudo, S. Szopa, and G. Zeng, 2013: Preindustrial to present day changes in tropospheric hydroxyl radical and methane lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). Atmos. Chem. Phys., 13, 5277-5298, doi:10.5194/acp-13-5277-2013.

"We have analysed time-slice simulations from 17 global models, participating in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), to explore changes in present-day (2000) hydroxyl radical (OH) concentration and methane (CH4) lifetime relative to preindustrial times (1850) and to 1980. A comparison of modeled and observation-derived methane and methyl chloroform lifetimes suggests that the present-day global multi-model mean OH concentration is overestimated by 5 to 10% but is within the range of uncertainties. The models consistently simulate higher OH concentrations in the Northern Hemisphere (NH) compared with the Southern Hemisphere (SH) for the present-day (2000; inter-hemispheric ratios of 1.13 to 1.42), in contrast to observation-based approaches which generally indicate higher OH in the SH although uncertainties are large. Evaluation of simulated carbon monoxide (CO) concentrations, the primary sink for OH, against ground-based and satellite observations suggests low biases in the NH that may contribute to the high north–south OH asymmetry in the models. The models vary widely in their regional distribution of present-day OH concentrations (up to 34%). Despite large regional changes, the multi-model global mean (mass-weighted) OH concentration changes little over the past 150 yr, due to concurrent increases in factors that enhance OH (humidity, tropospheric ozone, nitrogen oxide (NOx) emissions, and UV radiation due to decreases in stratospheric ozone), compensated by increases in OH sinks (methane abundance, carbon monoxide and non-methane volatile organic carbon (NMVOC) emissions). The large inter-model diversity in the sign and magnitude of preindustrial to present-day OH changes (ranging from a decrease of 12.7% to an increase of 14.6%) indicate that uncertainty remains in our understanding of the long-term trends in OH and methane lifetime. We show that this diversity is largely explained by the different ratio of the change in global mean tropospheric CO and NOx burdens (ΔCO/ΔNOx, approximately represents changes in OH sinks versus changes in OH sources) in the models, pointing to a need for better constraints on natural precursor emissions and on the chemical mechanisms in the current generation of chemistry-climate models. For the 1980 to 2000 period, we find that climate warming and a slight increase in mean OH (3.5±2.2%) leads to a 4.3±1.9% decrease in the methane lifetime. Analysing sensitivity simulations performed by 10 models, we find that preindustrial to present-day climate change decreased the methane lifetime by about four months, representing a negative feedback on the climate system. Further, we analysed attribution experiments performed by a subset of models relative to 2000 conditions with only one precursor at a time set to 1860 levels. We find that global mean OH increased by 46.4±12.2% in response to preindustrial to present-day anthropogenic NOx emission increases, and decreased by 17.3±2.3%, 7.6±1.5%, and 3.1±3.0% due to methane burden, and anthropogenic CO, and NMVOC emissions increases, respectively."
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 08, 2013, 12:18:34 AM
The linked reference (the link provides a free pdf) discusses factors that influence the radiative forcing potential for methane:

http://www.atmos-chem-phys.net/13/4907/2013/acp-13-4907-2013.html (http://www.atmos-chem-phys.net/13/4907/2013/acp-13-4907-2013.html)


Voulgarakis, A., D.T. Shindell, and G. Faluvegi, 2013: Linkages between ozone depleting substances, tropospheric oxidation and aerosols. Atmos. Chem. Phys., 13, 4907-4916, doi:10.5194/acp-13-4907-2013.

Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The individual historical radiative forcings of CFCs and N2O through their indirect effects on methane (-22.6 mW/m2 for CFCs and -6.7 mW/m2 for N2O) and sulfate aerosols (-3.0 mW/m2 for CFCs and +6.5 mW/m2 for N2O when considering the direct aerosol effect) discussed here are non-negligible when compared to known historical ODS forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate."
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 10, 2013, 01:12:06 AM
The attached NOAA image of atmospheric methane concentrations shows that the concentrations over Antarctica are lower than one to two weeks ago; which I believe adds support to my previously stated opinion that this methane is of marine origins (possibly from warm CDW melting submerged permafrost on the Antarctic continental shelves, thus releasing the gas previously trapped below the once relatively impermeable permafrost); in a manner similar to that occurring in the Northern Hemisphere (but shifted by about one half year in time).
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 20, 2013, 12:09:04 AM
A4R,

I finally got access to a Chrome system and visited the www.methanetracker.og (http://www.methanetracker.og) website, and I noted how much methane gas emissions that the tracker shows over the Southern Ocean that fall with the geopotential well shown in my post #58 of this thread.  Thus it is easy to image that these marine methane emissions could slowly find their way down to the bottom of the geopotential well, directly over Eastern Antartica.

Best,
ASLR
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on September 07, 2013, 09:07:42 PM
The following abstract is taken from the proceedings of the following IGSOC sponsored symposia.  This abstract provides a valuable update on the important topic methane generating microbes in the sediment beneath Antarctic glaciers/ice-sheets.  While not specific projections are made in the abstract, the abstract cites that further research will likely lead to new insights in this high risk factor for increasing radiative forcing as the Antarctic Ice Sheet retreats with time:


International Symposium on Changes in Glaciers and Ice Sheets: observations, modelling and environmental interactions; 28 July–2 August; Beijing, China; Contact: Secretary General, International Glaciological Society


http://www.igsoc.org/symposia/2013/beijing/proceedings/procsfiles/procabstracts_62.htm (http://www.igsoc.org/symposia/2013/beijing/proceedings/procsfiles/procabstracts_62.htm)



Microbial diversity and potential methanogenic activity in Antarctic subglacial sediment Wenkai YAN, Yu ZHANG, Xiang XIAO, Bo SUN, Yinke DOU, Hongmei MA
Corresponding author: Hongmei Ma
Corresponding author e-mail: mahongmei@pric.gov.cn
"The subglacial ecosystem has been recognized as an environment with considerable methanogenic activity and therefore has a significant impact on the global methane budget and is sensitive to climate change (Tung, Bramall and others, 2005). Although the presence and diversity of methanogens have been reported in a few subglacial environments (Stibal, Wadham and others, 2012), the in situ microbial activity is as yet insufficiently envisaged. Moreover, the responses of the main microbial players to changes in geochemical environments, e.g. as glaciers recede or advance, have not been well studied due to technical difficulties in sampling and cultivation. In this study, we attempted to answer the above questions by applying an integrated approach, including molecular analysis and in vitro simulation, to sediment samples from Antarctic glaciers. 16S rRNA-based diversity analysis revealed that Euryarchaeota is the only phylum detected while most of the Archaea found are of the Methanomicrobia class. Furthermore, a phylogenetic tree based on the functional gene (mcrA gene, the terminal enzyme complex in the methane generation pathway, which is a specific marker for methanogen) was constructed. Results showed that the methanogens from Antarctic subglacial environments are more similar to methanogens reported in freshwater sediment than to those from polar environments. These results provide us with evidence on the potential substrate utilization of subglacial methanogens. With this in mind, we can further incubate the sediment samples in the simulated conditions to estimate the in situ and potential microbial activities. Therefore, we will obtain a better understanding of the effect of glacier recession on the subgalcial ecosystem. This study will also help us to explore the evolutional process and cold-adaptation mechanisms of methanogenic microorganisms."
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on January 28, 2014, 01:03:10 AM
The attached image from NOAA (see link), presents the methane flask measurements from the South Pole atmosphere; which indicates that indeed methane concentrations were trending upward in 2013 as compared to earlier data:


http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts%5dhttp://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts%5dhttp://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on March 17, 2014, 07:37:11 AM
The attached image (from the linked NOAA source) shows atmospheric methane concentrations  measured at the South Pole by flasks, through January 2014

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)

This update from the last post shows that atmospheric methane concentrations at the South Pole are continuing to increase linearly.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on May 13, 2014, 10:15:32 PM
In multiple posts in this thread I have stated my concern that underwater methane hydrates may be dissociating in relatively shallow continental shelf waters (due to increases in water temperatures associated with AGW) in the Southern Hemisphere and then been transported by winds into the Antarctic atmosphere where they tend to accumulated in the austral winter due to the lower temperatures in that timeframe.  The following link, and quote, references just possible methane source of the coast of New Zealand in just 200m of water:


http://www.stuff.co.nz/environment/10039610/Methane-field-discovered-off-Gisborne-coast (http://www.stuff.co.nz/environment/10039610/Methane-field-discovered-off-Gisborne-coast)

Quote: "A "huge network" of frozen methane and methane gas has been discovered in ocean sediments 20 kilometres to 50km off Gisborne.
A joint New Zealand-German research team found 99 gas flares in a 50-square kilometre area, venting in columns up to 250 metres high, the National Institute of Water and Atmospheric Research (Niwa) said.
Methane was also found building up beneath a large landslide and being released along the landslide margin, and there were indications of large areas of methane hydrates - ice-like frozen methane - below the sea floor.
The discoveries were made by a 16-member team using state-of-the-art seismic and echosounder technology on board the Niwa research vessel Tangaroa.
The concentration of sea floor gas vents was the densest known off the New Zealand coast, and the vents were in much shallower water than usual.
Venting usually happened around a depth of 800m on large ridges in the middle of the continental slope, Niwa marine geologist and voyage leader Dr Joshu Mountjoy said.
In this case venting was going on along the edge of the shelf in as little as 200m of water.
The work is part of a larger project focused on the interaction between gas hydrates and and slow-moving active landslides. The area surveyed was known to have large active landslides, up to 15km long and 100m thick.
Researchers were also hoping to understand whether some methane was reaching the atmosphere, rather than being mixed up in the water column and consumed by biological processes as normally happened, Mountjoy said.
"Methane is a very effective greenhouse gas and seabed methane release has the potential to dramatically alter the earth's climate," he said.
"As ocean temperatures change the methane hydrate system has the potential to become unstable."
It would be interesting to find out whether global warming was changing the ocean system off Gisborne and causing more methane expulsion than previously. Higher ocean temperatures could change conditions so ice could turn back into a gas.
It remained to be seen whether the area off Gisborne was sensitive to climate change, Mountjoy said.
"We may be entering into a situation where global climate change is influencing the methane hydrate system."
The researchers were also trying to understand what caused the large, slow landslides in the area.
In a recently submitted scientific paper they proposed the landslides might be the sea floor equivalent of glaciers, with frozen methane rather than water ice. Alternatively pressurized gas could be causing landslides to move down slope."

See also the attached image of the methane gas leaks and the information at the following link:

http://www.niwa.co.nz/news/joint-new-zealand-german-3d-survey-reveals-massive-seabed-gas-hydrate-and-methane-system (http://www.niwa.co.nz/news/joint-new-zealand-german-3d-survey-reveals-massive-seabed-gas-hydrate-and-methane-system)

Also, to state the obvious, if the water depth is about 200-m and the column of methane bubbles in the water are about 250m tall, then a significant about of methane must be reaching the atmosphere.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on September 13, 2014, 04:35:21 PM
With a nod to Laurent who provided the link at the bottom of this post in the "What new in Antarctica?" thread; I thought that it would be a good idea to cross-link the reference below into this "Antarctic Methane Concentration" thread.  The reference provides clear, first-hand, observations of methane seeps from glacially-formed fjords and troughs on the northern shelf of the island of South Georgia (in the Southern Ocean).  The other posts in this thread make it clear that this example of methane seeps from South Georgia is but one first-hand case of numerous seasonally activated (possibly by seasonal [and longer-term] changes in the ocean currents) sub-sea methane seeps in the Southern polar and sub-polar ocean regions.

M. Römer et al.: First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia; in Earth and Planetary Science Letters 403 (2014), S. 166 – 177.

http://www.sciencedirect.com/science/article/pii/S0012821X1400421X (http://www.sciencedirect.com/science/article/pii/S0012821X1400421X)

Abstract: "An extensive submarine cold-seep area was discovered on the northern shelf of South Georgia during R/V Polarstern cruise ANT-XXIX/4 in spring 2013. Hydroacoustic surveys documented the presence of 133 gas bubble emissions, which were restricted to glacially-formed fjords and troughs. Video-based sea floor observations confirmed the sea floor origin of the gas emissions and spatially related microbial mats. Effective methane transport from these emissions into the hydrosphere was proven by relative enrichments of dissolved methane in near-bottom waters. Stable carbon isotopic signatures pointed to a predominant microbial methane formation, presumably based on high organic matter sedimentation in this region. Although known from many continental margins in the world's oceans, this is the first report of an active area of methane seepage in the Southern Ocean. Our finding of substantial methane emission related to a trough and fjord system, a topographical setting that exists commonly in glacially-affected areas, opens up the possibility that methane seepage is a more widespread phenomenon in polar and sub-polar regions than previously thought."

See also:
http://www.awi.de/en/news/press_releases/detail/item/greenhouse_gases_in_the_southern_ocean_first_evidence_of_active_methane_emission_at_the_antarctic_s/?tx_list_pi1 (http://www.awi.de/en/news/press_releases/detail/item/greenhouse_gases_in_the_southern_ocean_first_evidence_of_active_methane_emission_at_the_antarctic_s/?tx_list_pi1)
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on January 27, 2015, 08:05:15 PM
The attached South Pole atmospheric methane plot shows that the methane peak in November 2014 was above the recent (post 2006) trend line, see:

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)]http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts

Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2015, 01:12:09 AM
The first attached plot from the NOAA South Pole station with data through August 1 2015 shows that so far atmospheric methane concentrations are clearly accelerating with this past year's concentrations increasing at faster rate than the past several years.

The second attached NOAA satellite image of atmospheric methane concentration at 487 hPa on August 6 2015, shows that the concentrations about the Amundsen Sea Embayment, ASE, are over 2,000ppb (which is historically high); which makes me concerned that an El Nino driven influx of warm Circumpolar Deep Water, CDW, may be causing methane hydrates in the ASE seafloor to degrade at the highest rate of the satellite record.
Title: Re: Antarctic Methane Concentrations
Post by: seaice.de on August 07, 2015, 03:32:32 PM
The first attached plot from the NOAA South Pole station with data through August 1 2015 shows that so far atmospheric methane concentrations are clearly accelerating with this past year's concentrations increasing at faster rate than the past several years.

The second attached NOAA satellite image of atmospheric methane concentration at 487 hPa on August 6 2015, shows that the concentrations about the Amundsen Sea Embayment, ASE, are over 2,000ppb (which is historically high); which makes me concerned that an El Nino driven influx of warm Circumpolar Deep Water, CDW, may be causing methane hydrates in the ASE seafloor to degrade at the highest rate of the satellite record.

Well, you probably trace only artefacts in the satellite product, i.e. cloud fraction or temperature. Is there any peer-reviewed paper about the applicability of the retrieval method and its validation in Antarctica?  :-\
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2015, 03:50:45 PM
The first attached plot from the NOAA South Pole station with data through August 1 2015 shows that so far atmospheric methane concentrations are clearly accelerating with this past year's concentrations increasing at faster rate than the past several years.

The second attached NOAA satellite image of atmospheric methane concentration at 487 hPa on August 6 2015, shows that the concentrations about the Amundsen Sea Embayment, ASE, are over 2,000ppb (which is historically high); which makes me concerned that an El Nino driven influx of warm Circumpolar Deep Water, CDW, may be causing methane hydrates in the ASE seafloor to degrade at the highest rate of the satellite record.

Well, you probably trace only artefacts in the satellite product, i.e. cloud fraction or temperature. Is there any peer-reviewed paper about the applicability of the retrieval method and its validation in Antarctica?  :-\

While the second image in my post was by satellite, the first image is clearly labeled as reporting data gathered at the South Pole station by flasks.  Thus there is no question about the validity of the average flask trend line; however, if you want to read-up on the background of these plots, the first comes from the first link below, and the second image comes from the second link below:

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)]http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts
 
http://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi/index.html (http://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi/index.html)
Title: Re: Antarctic Methane Concentrations
Post by: seaice.de on August 07, 2015, 04:06:07 PM
The first attached plot from the NOAA South Pole station with data through August 1 2015 shows that so far atmospheric methane concentrations are clearly accelerating with this past year's concentrations increasing at faster rate than the past several years.

The second attached NOAA satellite image of atmospheric methane concentration at 487 hPa on August 6 2015, shows that the concentrations about the Amundsen Sea Embayment, ASE, are over 2,000ppb (which is historically high); which makes me concerned that an El Nino driven influx of warm Circumpolar Deep Water, CDW, may be causing methane hydrates in the ASE seafloor to degrade at the highest rate of the satellite record.

Well, you probably trace only artefacts in the satellite product, i.e. cloud fraction or temperature. Is there any peer-reviewed paper about the applicability of the retrieval method and its validation in Antarctica?  :-\

While the second image in my post was by satellite, the first image is clearly labeled as reporting data gathered at the South Pole station by flasks.  Thus there is no question about the validity of the average flask trend line; however, if you want to read-up on the background of these plots, the first comes from the first link below, and the second image comes from the second link below:

http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts (http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts)]http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=SPO&program=ccgg&type=ts
 
http://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi/index.html (http://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi/index.html)

I do trust the flask samples and was asking about a reference for the satellite retrieval in Antarctica. The IASI retrievals are provided with a quality flag. Have you ever looked at that?
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2015, 04:35:10 PM
I do trust the flask samples and was asking about a reference for the satellite retrieval in Antarctica. The IASI retrievals are provided with a quality flag. Have you ever looked at that?

The Infrared Atmospheric Sounding Interferometer (IASI) methane readings are reported four times a day, every day, and are subject to: source variations, atmospheric variations and instrument uncertainties; however, I am not interesting in tracking, or characterizing, these uncertainties.  If you want to, please do so.
Title: Re: Antarctic Methane Concentrations
Post by: seaice.de on August 07, 2015, 04:42:28 PM
I do trust the flask samples and was asking about a reference for the satellite retrieval in Antarctica. The IASI retrievals are provided with a quality flag. Have you ever looked at that?

The Infrared Atmospheric Sounding Interferometer (IASI) methane readings are reported four times a day, every day, and are subject to: source variations, atmospheric variations and instrument uncertainties; however, I am not interesting in tracking, or characterizing, these uncertainties.  If you want to, please do so.

If you are interested in real signals, i.e. the atmospheric methane variations, you have to average the data considering these uncertainties. Otherwise you only see noise and artefacts.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2015, 04:54:36 PM
I do trust the flask samples and was asking about a reference for the satellite retrieval in Antarctica. The IASI retrievals are provided with a quality flag. Have you ever looked at that?

The Infrared Atmospheric Sounding Interferometer (IASI) methane readings are reported four times a day, every day, and are subject to: source variations, atmospheric variations and instrument uncertainties; however, I am not interesting in tracking, or characterizing, these uncertainties.  If you want to, please do so.

If you are interested in real signals, i.e. the atmospheric methane variations, you have to average the data considering these uncertainties. Otherwise you only see noise and artefacts.

I have used the eyeball method to track the variations in the IASI readings for about 2-years now, and in my eyeball's opinion these readings are trending upward at about the same pace as the flask readings from the South Pole Station.  Whether or not any individual IASI reading indicates a "Dragon's Breath" of methane hydrate degradation from the Southern Ocean, is just as much speculation as it is in the Arctic region (of which Jason Box reports many such possible isolated "Dragon's Breath" events).  So while I agree that the IASI should not be taken as "proof"; I think that they can be taken as an invitation for oceanographers to take more appropriate in-situ readings for possible methane emissions from the seafloor as the ASE marine glacier grounding lines retreat (thus exposing previously protected bed soil formations to warm CDW).
Title: Re: Antarctic Methane Concentrations
Post by: seaice.de on August 07, 2015, 05:12:00 PM
I do trust the flask samples and was asking about a reference for the satellite retrieval in Antarctica. The IASI retrievals are provided with a quality flag. Have you ever looked at that?

The Infrared Atmospheric Sounding Interferometer (IASI) methane readings are reported four times a day, every day, and are subject to: source variations, atmospheric variations and instrument uncertainties; however, I am not interesting in tracking, or characterizing, these uncertainties.  If you want to, please do so.

If you are interested in real signals, i.e. the atmospheric methane variations, you have to average the data considering these uncertainties. Otherwise you only see noise and artefacts.

I have used the eyeball method to track the variations in the IASI readings for about 2-years now, and in my eyeball's opinion these readings are trending upward at about the same pace as the flask readings from the South Pole Station.  Whether or not any individual IASI reading indicates a "Dragon's Breath" of methane hydrate degradation from the Southern Ocean, is just as much speculation as it is in the Arctic region (of which Jason Box reports many such possible isolated "Dragon's Breath" events).  So while I agree that the IASI should not be taken as "proof"; I think that they can be taken as an invitation for oceanographers to take more appropriate in-situ readings for possible methane emissions from the seafloor as the ASE marine glacier grounding lines retreat (thus exposing previously protected bed soil formations to warm CDW).

Well, you could eyeball the images for another 10-years but you can't draw any valid conclusions if you ignore the uncertainties and quality flags. The eyeball method is just waste of time and misleading with this kind of noisy and biased satellite data. Perhaps try a scientific approach?
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2015, 05:27:32 PM
Well, you could eyeball the images for another 10-years but you can't draw any valid conclusions if you ignore the uncertainties and quality flags. The eyeball method is just waste of time and misleading with this kind of noisy and biased satellite data. Perhaps try a scientific approach?

As I stated previously, I am not interested in spending my time characterizing this signal noise and satellite bias; however, if you want to please do so.
Title: Re: Antarctic Methane Concentrations
Post by: seaice.de on August 07, 2015, 05:50:36 PM
Well, you could eyeball the images for another 10-years but you can't draw any valid conclusions if you ignore the uncertainties and quality flags. The eyeball method is just waste of time and misleading with this kind of noisy and biased satellite data. Perhaps try a scientific approach?

As I stated previously, I am not interested in spending my time characterizing this signal noise and satellite bias; however, if you want to please do so.

If you do not care about the quality of the data you should better stop posting this kind of satellite images. These level 2 products "are provided only for the purposes of demonstrative and experimental use by qualified remote sensing researchers or experienced meteorologists and oceanographers" as NOAA/NESDIS clearly states on their website.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on August 07, 2015, 06:03:39 PM
Well, you could eyeball the images for another 10-years but you can't draw any valid conclusions if you ignore the uncertainties and quality flags. The eyeball method is just waste of time and misleading with this kind of noisy and biased satellite data. Perhaps try a scientific approach?

As I stated previously, I am not interested in spending my time characterizing this signal noise and satellite bias; however, if you want to please do so.

If you do not care about the quality of the data you should better stop posting this kind of satellite images. These level 2 products "are provided only for the purposes of demonstrative and experimental use by qualified remote sensing researchers or experienced meteorologists and oceanographers" as NOAA/NESDIS clearly states on their website.

The satellite data that I have posted is absolutely not cherry-picked outliers.  Thus while I agree that these posted satellite image data by themselves do not make definitive statements; they can serve as reminders to individuals (scientists or otherwise) to look deeper into the question of the clearly increasing methane emission (clearly as indicated by the accompanying South Pole flask data); whether from subsea methane hydrate degradation; tropical rainforest distress; anthropogenic sources, or other sources.  So you can view them as reminders of a trend, or you can ignore them.
Title: Re: Antarctic Methane Concentrations
Post by: anotheramethyst on August 16, 2015, 06:42:47 AM
The first attached plot from the NOAA South Pole station with data through August 1 2015 shows that so far atmospheric methane concentrations are clearly accelerating with this past year's concentrations increasing at faster rate than the past several years.

The second attached NOAA satellite image of atmospheric methane concentration at 487 hPa on August 6 2015, shows that the concentrations about the Amundsen Sea Embayment, ASE, are over 2,000ppb (which is historically high); which makes me concerned that an El Nino driven influx of warm Circumpolar Deep Water, CDW, may be causing methane hydrates in the ASE seafloor to degrade at the highest rate of the satellite record.

thanks for sharing the info, aSLR.  while the satellite image isn't definitive, i agree that it's worth noting, particularly since atmospheric methane is so much higher than preindustrial levels and so under reported.  i find methane rise in general quite worrisome.  thanks for keeping us updated.  :)
Title: Re: Antarctic Methane Concentrations
Post by: oren on August 16, 2015, 12:56:11 PM
The first attached plot from the NOAA South Pole station with data through August 1 2015 shows that so far atmospheric methane concentrations are clearly accelerating with this past year's concentrations increasing at faster rate than the past several years.

The second attached NOAA satellite image of atmospheric methane concentration at 487 hPa on August 6 2015, shows that the concentrations about the Amundsen Sea Embayment, ASE, are over 2,000ppb (which is historically high); which makes me concerned that an El Nino driven influx of warm Circumpolar Deep Water, CDW, may be causing methane hydrates in the ASE seafloor to degrade at the highest rate of the satellite record.

thanks for sharing the info, aSLR.  while the satellite image isn't definitive, i agree that it's worth noting, particularly since atmospheric methane is so much higher than preindustrial levels and so under reported.  i find methane rise in general quite worrisome.  thanks for keeping us updated.  :)

Totally agree. If we only wait for absolute verified sources of which all uncertainties are quantified, we'll be very late to recognize any trend, and we don't have that much time on our hands.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on January 11, 2016, 11:42:36 PM
Per the attached NOAA plot of the South Pole atmospheric methane concentration through January 9, 2016, the methane concentrations clearly accelerated after August 1, 2015 (the low point of the red portion of the curve).  This is not a good sign.
Title: Re: Antarctic Methane Concentrations
Post by: crandles on January 12, 2016, 01:12:17 PM
While 99 showed acceleration, that seems well after the 97/98 El Nino whereas this seems before current El Nino reached its peak so it seems hard to attribute it to just an El Nino effect.

Even so short term fluctuation or long term trend turning point?

Poles showing increases but Mauna Loa not
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.esrl.noaa.gov%2Fgmd%2Fwebdata%2Fiadv%2Fccgg%2Fgraphs%2Fccgg.MLO.ch4.1.none.discrete.all.png&hash=7c3c803dcd1490538f90dd56e30fdba4)http://www.esrl.noaa.gov/gmd/webdata/iadv/ccgg/graphs/ccgg.MLO.ch4.1.none.discrete.all.png (http://www.esrl.noaa.gov/gmd/webdata/iadv/ccgg/graphs/ccgg.MLO.ch4.1.none.discrete.all.png)

I would guess it seems more likely to be regional sources becoming more active rather than local or global as there isn't likely to be much local sources or sinks near south pole.

Certainly concerning if it continues.

Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on January 12, 2016, 05:24:59 PM
While 99 showed acceleration, that seems well after the 97/98 El Nino whereas this seems before current El Nino reached its peak so it seems hard to attribute it to just an El Nino effect.

Even so short term fluctuation or long term trend turning point?

Poles showing increases but Mauna Loa not

I would guess it seems more likely to be regional sources becoming more active rather than local or global as there isn't likely to be much local sources or sinks near south pole.

Certainly concerning if it continues.

I generally agree with your observations, and I note that a local source of methane near the South Pole seems particularly disturbing to me, if true, as any significant methane emissions from the Southern Ocean are most certainly not in any climate model forecasts for 2015.
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on January 13, 2016, 03:49:02 PM
While 99 showed acceleration, that seems well after the 97/98 El Nino whereas this seems before current El Nino reached its peak so it seems hard to attribute it to just an El Nino effect.

Even so short term fluctuation or long term trend turning point?

Poles showing increases but Mauna Loa not

I would guess it seems more likely to be regional sources becoming more active rather than local or global as there isn't likely to be much local sources or sinks near south pole.

Certainly concerning if it continues.

I generally agree with your observations, and I note that a local source of methane near the South Pole seems particularly disturbing to me, if true, as any significant methane emissions from the Southern Ocean are most certainly not in any climate model forecasts for 2015.

Robert Scribbler just made the following relevant post about methane (with a GWP10 of 130) and carbon dioxide.  When looking a Scribbler's data indicates local Arctic methane concentrations approaching 3,000 ppb, and the South Pole data showing high local methane concentrations; taken at face value such data would indicate that Polar Amplification is triggering methane emissions from these polar regions faster than natural emissions from other parts of the global.  That said, I am concerned that when the next La Nina induced rainforest floods come they will submerge much of the dead vegetation killed by the current drought, which would then produce methane emissions spikes from tropical rainforests.

http://robertscribbler.com/2016/01/12/the-ominous-greenhouse-gas-accumulation-continues-peak-methane-approaches-3000-parts-per-billion-as-co2-growth-rate-jumps-higher/ (http://robertscribbler.com/2016/01/12/the-ominous-greenhouse-gas-accumulation-continues-peak-methane-approaches-3000-parts-per-billion-as-co2-growth-rate-jumps-higher/)

Extract: "But the very pertinent question must be asked — are we waking up fast enough? And the still rapidly growing concentrations of gasses that heat the Earth’s atmosphere would seem to supply the answer in the form of a resounding, thunderous — “NO!”"
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on December 04, 2017, 09:59:39 PM
The linked reference discusses how gas hydrates in the bed sediment beneath marine glaciers can cause 'sticky spots' that can regulate ice stream flow rates:

Winsborrow, M., K. Andreassen, A. Hubbard, A. Plaza-Faverola, E. Gudlaugsson and H. Patton (2016). "Regulation of ice stream flow through subglacial formation of gas hydrates." Nature Geosci 9(5): 370-374, DOI: 10.1038/NGEO2696

https://www.nature.com/articles/ngeo2696
&
http://www.nature.com/articles/ngeo2696.epdf?referrer_access_token=IHHHsNRUI3lD2eFpTMWvl9RgN0jAjWel9jnR3ZoTv0N6H6twa9eus1zouX_OVF0HHps81v4XTc0_11DCSpeGLDxz98tw1yul2mr16lbVJL4uOjHYggNVEvnorXQDpPb-4F8Dx03N10vp8xTpF1OSQUCQuGQbrx_agiKHwJMiE0Vb3p9RlZE1kgUDa_7CPZDbIHfa0-zC2RtwAc1-HEOzfwPw5ovCnEJWlCwr6K4nmQjxYGctlb4MLBBjUrGaOUBg&tracking_referrer=austhrutime.com

 Abstract: "Variations in the flow of ice streams and outlet glaciers are a primary control on ice sheet stability, yet comprehensive understanding of the key processes operating at the ice–bed interface remains elusive. Basal resistance is critical, especially sticky spots—localized zones of high basal traction—for maintaining force balance in an otherwise well-lubricated/high-slip subglacial environment. Here we consider the influence of subglacial gas-hydrate formation on ice stream dynamics, and its potential to initiate and maintain sticky spots. Geophysical data document the geologic footprint of a major palaeo-ice-stream that drained the Barents Sea–Fennoscandian ice sheet approximately 20,000 years ago. Our results reveal a ∼250 km sticky spot that coincided with subsurface shallow gas accumulations, seafloor fluid expulsion and a fault complex associated with deep hydrocarbon reservoirs. We propose that gas migrating from these reservoirs formed hydrates under high-pressure, low-temperature subglacial conditions. The gas hydrate desiccated, stiffened and thereby strengthened the subglacial sediments, promoting high traction—a sticky spot— that regulated ice stream flow. Deep hydrocarbon reservoirs are common beneath past and contemporary glaciated areas, implying that gas-hydrate regulation of subglacial dynamics could be a widespread phenomenon."

Also see:

Title: "Regulation of Ice Stream Flow Through Subglacial Formation of Gas Hydrates"

http://austhrutime.com/ice_stram_flow_regulation_subglacial_gas_hydrates.htm

Extract: "Based on the presence of extensive sedimentary basins and modelling studies (Wadham et al., 2012; Wallmann et al., 2012) it is proposed that abundant gas hydrate accumulations are present beneath the ice sheets of Greenland and Antarctica. Also, gas hydrates have been identified in ice core samples obtained from above the subglacial Lake Vostok in East Antarctica (Uchida et al., 1994). The role of potentially widespread gas hydrate reservoirs in the modification of the thermomechanical regime at the base of contemporary ice sheets, which makes them critically sensitive, as well as their impact on ice steam force balance and dynamics has, so far, not been recognised. This control that was previously unforeseen, given the current lack of knowledge with regard to the distribution of gas hydrate, represents a significant unknown in attempts to model the current and future discharge and evolution of contemporary ice sheets, as well as their contribution to rising global sea levels."
Title: Re: Antarctic Methane Concentrations
Post by: AbruptSLR on July 22, 2020, 05:20:56 PM
The linked reference discusses how gas hydrates in the bed sediment beneath marine glaciers can cause 'sticky spots' that can regulate ice stream flow rates:

Winsborrow, M., K. Andreassen, A. Hubbard, A. Plaza-Faverola, E. Gudlaugsson and H. Patton (2016). "Regulation of ice stream flow through subglacial formation of gas hydrates." Nature Geosci 9(5): 370-374, DOI: 10.1038/NGEO2696

https://www.nature.com/articles/ngeo2696
&
http://www.nature.com/articles/ngeo2696.epdf?referrer_access_token=IHHHsNRUI3lD2eFpTMWvl9RgN0jAjWel9jnR3ZoTv0N6H6twa9eus1zouX_OVF0HHps81v4XTc0_11DCSpeGLDxz98tw1yul2mr16lbVJL4uOjHYggNVEvnorXQDpPb-4F8Dx03N10vp8xTpF1OSQUCQuGQbrx_agiKHwJMiE0Vb3p9RlZE1kgUDa_7CPZDbIHfa0-zC2RtwAc1-HEOzfwPw5ovCnEJWlCwr6K4nmQjxYGctlb4MLBBjUrGaOUBg&tracking_referrer=austhrutime.com

 Abstract: "Variations in the flow of ice streams and outlet glaciers are a primary control on ice sheet stability, yet comprehensive understanding of the key processes operating at the ice–bed interface remains elusive. Basal resistance is critical, especially sticky spots—localized zones of high basal traction—for maintaining force balance in an otherwise well-lubricated/high-slip subglacial environment. Here we consider the influence of subglacial gas-hydrate formation on ice stream dynamics, and its potential to initiate and maintain sticky spots. Geophysical data document the geologic footprint of a major palaeo-ice-stream that drained the Barents Sea–Fennoscandian ice sheet approximately 20,000 years ago. Our results reveal a ∼250 km sticky spot that coincided with subsurface shallow gas accumulations, seafloor fluid expulsion and a fault complex associated with deep hydrocarbon reservoirs. We propose that gas migrating from these reservoirs formed hydrates under high-pressure, low-temperature subglacial conditions. The gas hydrate desiccated, stiffened and thereby strengthened the subglacial sediments, promoting high traction—a sticky spot— that regulated ice stream flow. Deep hydrocarbon reservoirs are common beneath past and contemporary glaciated areas, implying that gas-hydrate regulation of subglacial dynamics could be a widespread phenomenon."

Also see:

Title: "Regulation of Ice Stream Flow Through Subglacial Formation of Gas Hydrates"

http://austhrutime.com/ice_stram_flow_regulation_subglacial_gas_hydrates.htm

Extract: "Based on the presence of extensive sedimentary basins and modelling studies (Wadham et al., 2012; Wallmann et al., 2012) it is proposed that abundant gas hydrate accumulations are present beneath the ice sheets of Greenland and Antarctica. Also, gas hydrates have been identified in ice core samples obtained from above the subglacial Lake Vostok in East Antarctica (Uchida et al., 1994). The role of potentially widespread gas hydrate reservoirs in the modification of the thermomechanical regime at the base of contemporary ice sheets, which makes them critically sensitive, as well as their impact on ice steam force balance and dynamics has, so far, not been recognised. This control that was previously unforeseen, given the current lack of knowledge with regard to the distribution of gas hydrate, represents a significant unknown in attempts to model the current and future discharge and evolution of contemporary ice sheets, as well as their contribution to rising global sea levels."

I remind readers that if the Byrd Subglacial Basin, BSB, were to sustain an MICI-type of collapse in the coming decades that it is probably that a meaningful about of methane would be released from the methane hydrates in the bed of the Thwaites, and adjoining, glaciers.