If they concentrated on looking only in Marion County they missed it. It clearly is in far southwestern Winston County due south of Haleyville on a line between there and Eldridge that places it a little over 3/4 mile west of Hwy 13 pretty close to the half-moon shaped pond on the headwaters of Dry Creek.
If they would focus their search on a radius of about 5 miles from that location they will probably have more likely candidates to consider. There is a small community on the curve in Hwy 13 south of the Hwy 9/13 intersection and further west of that there is an active quarry. It doesn't look like coal but I can't be sure. Anyway, though this is at the NE edge of the Black Warrior basin I don't see any active production.
EDIT: I wanted to add that there has been frac activity in the Black Warrior Basin for about 10 years. It is mostly south of there. That basin has been productive for a long time so there is a high likelihood that there are old wells that have not been plugged, they are simply abandoned and many could be essentially open-hole. That would be an obvious path for hydrocarbons to reach the surface and it would definitely not be the only time it has happened. I know from experience that fracking a well can cause pressure and production increases in connected wells 10s of miles away if the fracked interval is connected in the subsurface. Pressure always moves from high pressure to low pressure while it equalizes. This area is also the southwestern extension of the Appalachian coal trend. There could be some coal activity locally.
Apparently this satellite (the Sentinel-5p) has a 7 x 7km resolution. [1] There are other satellites with much higher resolution that might be used to narrow it down, and more launching soon.
"An emissions rate of about 58 tons of methane per hour would have been required to generate the plume, according to an estimate from Kayrros SAS, which analyzed European Space Agency data."
Maybe hard for surveillance though? A single railcar of liquid is 100 tons (I don't know if liquid methane is shipped, this is just a way to visualize - and this is a rough number. Methane is about 12 pct lighter than water.)
I wonder what the most likely reasons are. I might think a fracking based earthquake opening up an underground reservoir that feeds into a mine? But that is very speculative! I am assuming there are no chemical plants in the area.
For context [0] says global annual methane generation is ~570E6 tons, which puts hourly production at 570E6/(24*365)~=65000 or over a thousand times this source. Like, not /great/ definitely want to address. But unless it's a symptom of a new mechanism I don't know if I should be super alarmed.
> The EPA said that the potential area is too broad and the satellite data “does not provide enough tangible information of potential sources in which to conduct a programmatic review,”
Perhaps we should have airplanes/drones fitted with similar measurement instruments as the satellite, so we can take a closer look when necessary?
The company Aclima (https://www.aclima.io/) has a commercial business in which they pay drivers to drive around and collect air quality data, including methane concentration. Originally they co-located the sensors on the Google StreetMap vehicles, but now they run their own fleet. I don't think they've made it out to rural Alabama quite yet, though. . .
We tried measuring carbon monoxide also but CO is lighter than air so we got no measurements. Methane is also lighter than air and would probably not be measurable on the ground unless you were very close to the source. However, the biker could carry a drone with a methane sensor and launch it periodically:
I wanted to add radiation sensors to the bikes but the prof vetoed that idea, afraid it might affect property values in the town if we actually found differences in radiation levels.
Has anyone made a generic "I am willing to carry one or more sensors on my bicycle, and criss-cross an area as long as software tells me where I need to go next" app that we can all use to congregate sensor readings with?
Methane, decibel levels, all sorts of opportunities here.
Readit News
If they would focus their search on a radius of about 5 miles from that location they will probably have more likely candidates to consider. There is a small community on the curve in Hwy 13 south of the Hwy 9/13 intersection and further west of that there is an active quarry. It doesn't look like coal but I can't be sure. Anyway, though this is at the NE edge of the Black Warrior basin I don't see any active production.
Here are a few pics I put together for grins.
https://postimg.cc/gallery/phsPyBJ
EDIT: I wanted to add that there has been frac activity in the Black Warrior Basin for about 10 years. It is mostly south of there. That basin has been productive for a long time so there is a high likelihood that there are old wells that have not been plugged, they are simply abandoned and many could be essentially open-hole. That would be an obvious path for hydrocarbons to reach the surface and it would definitely not be the only time it has happened. I know from experience that fracking a well can cause pressure and production increases in connected wells 10s of miles away if the fracked interval is connected in the subsurface. Pressure always moves from high pressure to low pressure while it equalizes. This area is also the southwestern extension of the Appalachian coal trend. There could be some coal activity locally.
[1] https://en.m.wikipedia.org/wiki/Sentinel-5
The Wikipedia pages claims that pictures are taken every second but I am not sure how that translates to image density on the ground.
There is a lot of work done to try and reverse advect plumes using tropospheric wind data... But it's not an easy problem
That sounds like a lot!
I wonder what the most likely reasons are. I might think a fracking based earthquake opening up an underground reservoir that feeds into a mine? But that is very speculative! I am assuming there are no chemical plants in the area.
[0] https://www.iea.org/reports/methane-tracker-2020
Perhaps we should have airplanes/drones fitted with similar measurement instruments as the satellite, so we can take a closer look when necessary?
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High-Resolution Air Pollution Mapping with Google Street View Cars: Exploiting Big Data https://pubs.acs.org/doi/10.1021/acs.est.7b00891
https://www.cs.dartmouth.edu/~sensorlab/pubs/BikeNet-SenSys0...
http://sensorlab.cs.dartmouth.edu/pubs/a6-eisenman.pdf
We tried measuring carbon monoxide also but CO is lighter than air so we got no measurements. Methane is also lighter than air and would probably not be measurable on the ground unless you were very close to the source. However, the biker could carry a drone with a methane sensor and launch it periodically:
https://www.ravanair.com/drone-uav-methane-gas-detection/
Maybe a laser could be mounted on the bike firing straight up and be used to detect methane?:
https://www.crowcon.com/products/portables/lmm-gen-2/
I wanted to add radiation sensors to the bikes but the prof vetoed that idea, afraid it might affect property values in the town if we actually found differences in radiation levels.
Methane, decibel levels, all sorts of opportunities here.
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