Monday, 19 June 2017

A new scientic paper from Natalia Shakhova and Igor Semiletov


In their discussion Paul Beckwith and Alex Smith of Radio Eco Shock made reference to a paper being released in June that talks of an eightfold increase in methane emissions in Siberia.

Have methane emissions in
East Siberian Shelf increased 800%?

Here is the discussion 

Listen to "New paper by Semiletov and Shakhova on methane hydrates" on Spreaker.

And the Reddit item they refer to- 

Eight times higher is like an 800% increase. Natalia Shakhova and Igor Semiletov will release a paper soon detailing this explosive data. This duo have been studying methane emission in the arctic for nearly 20 years. They first brought this to our attention in 2011, and were roundly poo pooed by computer model jocks, Gavin Schmidt and Michael Man. Thanks dylanoliver233.



Thanks to Robert Leisure for finding what looks like the latest paper.

These are his notes- 


Is this it? 
Published: 9 June 2017 , Natalia Shakhova, and Igor Semiletov
The East Siberian Arctic Shelf, the world’s largest and shallowest shelf (covering 2.1 × 106 km2) containing the largest area of sub-merged permafrost, contains vast CH4 deposits as subsea permafrost, CH4 hydrates, and natural gas reservoirs. Reservoir estimates are ∼ 10 000 Gt (1 Gt = 1015 g) of CH4 hydrates.
Atmospheric release of just 0.5 % of the Arctic shelf hydrate CH4 will cause abrupt climate change.




Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea



Ira Leifer1,Denis Chernykh2,3, Natalia Shakhova3,4, and Igor Semiletov2,3,4
1 Bubbleology Research International, Solvang, CA 93463, USA
2 Russian Academy of Science, Pacific Oceanological Institute, Vladivostok, Russia
3 Tomsk Polytechnic University, Tomsk, Russia
4 University Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK 99775, USA
Received: 23 Jun 2016 – Discussion started: 07 Jul 2016
Revised: 06 Feb 2017 – Accepted: 06 Feb 2017 – Published: 09 Jun 2017

Abstract. Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes spanning 0.019 to 1.1 L s−1 to derive the in situ calibration curve (Q(σ)). These nonlinear curves related flux (Q) to sonar return (σ) for a multibeam echosounder (MBES) and a single-beam echosounder (SBES) for a range of depths. The analysis demonstrated significant multiple bubble acoustic scattering – precluding the use of a theoretical approach to derive Q(σ) from the product of the bubble σ(r) and the bubble size distribution where r is bubble radius. The bubble plume σ occurrence probability distribution function (Ψ(σ)) with respect to Q found Ψ(σ) for weak σ well described by a power law that likely correlated with small-bubble dispersion and was strongly depth dependent. Ψ(σ) for strong σ was largely depth independent, consistent with bubble plume behavior where large bubbles in a plume remain in a focused core. Ψ(σ) was bimodal for all but the weakest plumes.


Q(σ) was applied to sonar observations of natural arctic Laptev Sea seepage after accounting for volumetric change with numerical bubble plume simulations. Simulations addressed different depths and gases between calibration and seep plumes. Total mass fluxes (Qm) were 5.56, 42.73, and 4.88 mmol s−1 for MBES data with good to reasonable agreement (4–37 %) between the SBES and MBES systems. The seepage flux occurrence probability distribution function (Ψ(Q)) was bimodal, with weak Ψ(Q) in each seep area well described by a power law, suggesting primarily minor bubble plumes. The seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.



Citation: Leifer, I., Chernykh, D., Shakhova, N., and Semiletov, I.: Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea, The Cryosphere, 11, 1333-1350, https://doi.org/10.5194/tc-11-1333-2017, 2017.

The paper is available in PDF HERE

Natalia Shakhova appeared in the following video about a month ago



Methane takes the quick way out - 

Here is another paper published this month

K. Andreassen1,*, A. Hubbard1, M. Winsborrow1, H. Patton1, S. Vadakkepuliyambatta1, A. Plaza-Faverola1, E. Gudlaugsson1, P. Serov1, A. Deryabin2, R. Mattingsdal2, J. Mienert1, S. Bünz1
2 June, 2017

Methane takes the quick way out

Accounting for all the sources and sinks of methane is important for determining its concentration in the atmosphere. Andreassen et al. found evidence of large craters embedded within methane-leaking subglacial sediments in the Barents Sea, Norway. 
They propose that the thinning of the ice sheet at the end of recent glacial cycles decreased the pressure on pockets of hydrates buried in the seafloor, resulting in explosive blow-outs. 
This created the giant craters and released large quantities of methane into the water above.
Science, this issue p. 948

Abstract

Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained. 
We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion. 
Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates. 
Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters. We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets.




3 comments:

  1. We are living through a ecoillogical bubble!

    ReplyDelete
  2. Pray, what does 'scientic' mean, this is a new term to me.

    ReplyDelete
  3. This stuff just doesn't make the mainstream media. Bsdic science literacy in the general population is very low. It's not possible to use science based arguments with most deniers.

    ReplyDelete