Tag Archives: monitoring pollution

God’s Channels: How to Hear Whales and Bomb Explosions

About 1 kilometer under the sea lies a sound tunnel that carries the cries of whales and the clamor of submarines across great distances. Ever since scientists discovered this Sound Fixing and Ranging (SOFAR) channel in the 1940s, they’ve suspected a similar conduit exists in the atmosphere. But few have bothered to look for it, aside from one top-secret Cold War operation.

Today by listening to distant rocket launches with solar-powered balloons, researchers say they have finally detected hints of an aerial sound channel, although it does not seem to function as simply or reliably as the ocean SOFAR. If confirmed, the atmospheric SOFAR may pave the way for a network of aerial receivers that could help researchers detect remote explosions from volcanoes, bombs, and other sources that emit infrasound—acoustic waves below the frequency of human hearing.

After geophysicist Maurice Ewing discovered the SOFAR channel in 1944, he set out to find an analogous layer in the sky. At an altitude of between 10 and 20 kilometers is the tropopause, the boundary between the troposphere, the lowest layer of the atmosphere (where weather occurs), and the stratosphere. Like the marine SOFAR, the tropopause represents a cold region, where sound waves should travel slower and farther. An acoustic waveguide in the atmosphere, Ewing reasoned, would allow the U.S. Air Force to listen for nuclear weapon tests detonated by the Soviet Union. He instigated a top-secret experiment, code-named Project Mogul, that sent up hot air balloons equipped with infrasound microphones. The instruments often malfunctioned in the high winds, and in 1947, debris from one balloon crashed just outside of Roswell, New Mexico; that crash sparked one of the most famous UFO conspiracy theories in history. Soon after, the military disbanded the project. But the mission wasn’t declassified for nearly 50 years…

[Today] researchers plan to listen to launches of rockets with multiple solar-powered balloons staggered at different altitudes to figure out where the channel’s effects are strongest. They also plan to test the range of the signals and investigate the mysterious background noise. Understanding how the channel functions could help lay the groundwork for a future aerial infrasound network, which would monitor Earth constantly for major explosions and eruptions.

Excerpts from Zack Savisky, Balloon Detects First Signs of a ‘Sound Tunnel’ in the Sky, Science, Apr. 27, 2022

5,000 Eyes in the Sky: environmental monitoring

The most advanced satellite to ever launch from Africa will soon be patrolling South Africa’s coastal waters to crack down on oil spills and illegal dumping.  Data from another satellite, this one collecting images from the Texas portion of a sprawling oil and gas region known as the Permian Basin, recently delivered shocking news: Operators there are burning off nearly twice as much natural gas as they’ve been reporting to state officials.

With some 5,000 satellites now orbiting our planet on any given day…. They will help create a constantly innovating industry that will revolutionize environmental monitoring of our planet and hold polluters accountable…

A recent study by Environmental Defense Fund focused on natural gas flares from the wells in the Permian Basin, located in Western Texas and southeastern New Mexico. Our analysis proved that the region’s pollution problem was much larger than companies had revealed.  A second study about offshore gas flaring in the Gulf of Mexico, published by a group of scientists in the Geophysical Research Letters, showed that operators there burn off a whopping 40% of the natural gas they produce.

Soon a new satellite will be launching that is specifically designed not just to locate, but accurately measure methane emissions from human-made sources, starting with the global oil and gas industry.  MethaneSAT, a new EDF affiliate unveiled in 2018, will launch a future where sensors in space will find and measure pollution that today goes undetected. This compact orbital platform will map and quantify methane emissions from oil and gas operations almost anywhere on the planet at least weekly.

Excerpts from Mark Brownstein, These pollution-spotting satellites are just a taste of what’s to come, EDF, Apr. 4, 2019

Underwater Robots against Pollution

Subcultron is a swarm of at least 120 self-directing, underwater robots being developed by scientists in six countries to monitor Venice’s polluted waterways and transmit environmental data to government officials.The robots, shaped like fish, mussels, and lily pads to mimic the species’ hydrodynamics, carry sensors to monitor water conditions like temperature and chemical composition…The swarm communicates via the Internet-capable lily pads…
The robots use lithium ion batteries and solar cells for power. (Yes, enough sunlight gets through.)Some of the robots carry cameras. Others have electrodes that allow them to “see” by measuring objects crossing the electric fields they generate.Using wireless signals, human monitors can take over from the swarm’s AI software if something goes wrong. The European Commission has granted the project €4 million ($4.4 million).
Thomas Schmickl, the inventor, …..plans to build robot swarms that can monitor the oceans or even faraway moons that have water.

Excerpts from Innovation Subcultron, Bloomberg Business Week, Jan. 28, 2016