Feeds:
Posts
Comments

Posts Tagged ‘atmosphere’

Photo: NOAA (National Oceanic and Atmospheric Administration).
Lightning as seen from the Geostationary Lightning Mapper on NOAA’s GOES-16 satellite from April 29, 2020. The World Meteorological Organization has found that one of the lightning flashes within this thunderstorm complex was the longest flash on record, covering a horizontal distance of 477 miles.

Let’s talk about natural phenomena. Let’s talk about lightning. Can you imagine one flash covering 477 miles? That’s the record, set in 2020. Here’s Matthew Cappucci‘s January article for the Washington Post about such megaflashes.

Capupucci wrote, “The World Meteorological Organization announced on Monday that it had confirmed two new mind-blowing lightning ‘megaflash’ records. The findings, which come after careful data-checking and rigorous certification processes, include one record event that occurred over the Lower 48 states.

“On April 29, 2020, a sprawling mass of strong to severe thunderstorms produced a 477.2-mile-long lightning strike over the southern United States. It stretched from near Houston to southeast Mississippi, a distance equivalent to that between Columbus, Ohio, and New York City. …

“The WMO also identified a new world record for the long-lasting lightning flash. It lit up the skies over Uruguay and northern Argentina for 17.1 seconds on June 18, 2020. …

“ ‘These are extraordinary records from single lightning flash events,’ wrote Randall Cerveny, rapporteur of Weather and Climate Extremes for WMO, in a statement.

“Megaflashes dwarf ordinary lightning strikes. As Earth dwellers, we’re accustomed to seeing what’s going on near the ground, including conventional cloud-to-ground lightning bolts. …

“Megaflashes are different. They’re enormous. They snake through regions of high electric field and can travel for hundreds of miles while lasting more than 10 seconds. Since most storm clouds are fewer than 10 miles high, lightning can’t grow terribly long in the vertical direction. But megaflashes have plenty of space to sprawl in the horizontal.

“All megaflashes accompany MCSs, or mesoscale convective systems. MCSs are clusters of thunderstorms that often rage overnight and can occupy an area the size of several states, last for hours and stretch 750 miles or more end-to-end. They’re a staple of the spring and early summer across the southern and central United States, and are also common in Brazil, Argentina and Uruguay. South America’s ‘Altiplano,’ or high Andean Plateau, also brews prolific lightning-producing storms.

“Megaflashes crawl through the clouds but can produce or induce ground connections at various points. Sometimes MCSs merge, leading to amplified and more chaotic electric fields that can also be supportive of megaflashes. Covering so much real estate means megaflashes flicker for an extended duration.

“While atmospheric electrodynamicists had long since theorized about the existence of megaflashes, the scale and duration of said flashes was not well-understood until recently. …

“ ‘Detecting these extreme lightning events is very difficult due to their exceptional rarity and scale,’ wrote Michael J. Peterson of the Space and Remote Sensing Group at Los Alamos National Laboratory, in an email. ‘Your sensor has to be in just the right place at perfectly the right time to be able to see it — and the instrument has to be capable of measuring something as large as a megaflash.’ …

“That changed with the Nov. 19, 2016, launch of the GOES East weather satellite, soon followed by GOES West. Both peer down on North America from 22,236 miles above Earth and have ‘Geostationary Lighting Mappers,’ or instruments that are able to discern the infrared signal associated with a lightning flash. That allows for the tracking of cloud-to-cloud and intracloud flashes from above. …

“Megaflashes may be more common than once believed. Now that scientists are able to spot and resolve them over North America, they’re able to begin constructing a catalogue of events. One particularly impressive discharge, which eventually spanned 300 miles but was not evaluated by the WMO, occurred on the morning of Oct. 23, 2017. A thunderstorm was raging near Thackerville, Okla., a little more than an hour’s drive north of the Dallas-Fort Worth Metroplex. A lightning strike illuminated skies near the Red River — Oklahoma’s southern border — at 12:13 a.m.

“At the same time, the landscape was also aglow near Burlington, Kansas; the same massive 300 mile-long lightning bolt had illuminated an area four times larger than the state of Connecticut.”

More at the Post, here. I wonder what Philip Pullman, author of the amazing Golden Compass fantasy series, could do with this. His powerful imagination already has done a lot with electromagnetic waves.

Read Full Post »

Erik’s running buddy passed along a BBC story suggesting that cutting back on meat could have value for the planet.

Interestingly, that was the premise of Frances Moore Lappé‘s 1971 bestseller, Diet for a Small Planet, which my sister got me interested in when she was a vegetarian.

At the BBC, environment analyst Roger Harrabin notes research that confirms some of Lappé’s predictions.

“Research from Cambridge and Aberdeen universities estimates greenhouse gases from food production will go up 80% if meat and dairy consumption continues to rise at its current rate. That will make it harder to meet global targets on limiting emissions.

“The study urges eating two portions of red meat and seven of poultry per week. However that call comes as the world’s cities are seeing a boom in burger restaurants. …

“If [the trend] continues, more and more forest land or fields currently used for arable crops will be converted for use by livestock as the world’s farmers battle to keep up with demand.

“Deforestation will increase carbon emissions, and increased livestock production will raise methane levels and wider fertiliser use will further accelerate climate change. The lead researcher, Bojana Bajzelj from the University of Cambridge, said: ‘There are basic laws of biophysics that we cannot evade.’

“The average efficiency of livestock converting plant feed to meat is less than 3%, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals that provide meat for humans.” Read more here. And consider going in for mushroom burgers.

I only ever made the eggplant casserole Diet for a Small Planet, but it sure was yummy.

Photo: CiteLighter-Cards
In 1971, Frances Moore Lappé wrote that raising animals for food takes resources better used elsewhere. It can also put too much methane into the atmosphere.

Read Full Post »

Joe Palca, at National Public Radio, recently had a nice report about astronomy and optics.

I thought of John and his OpticsForHire team.

“It used to be that if astronomers wanted to get rid of the blurring effects of the atmosphere,” says Palca, “they had to put their telescopes in space. But a technology called adaptive optics has changed all that.

“Adaptive optics systems use computers to analyze the light coming from a star, and then compensate for changes wrought by the atmosphere, using mirrors that can change their shapes up to 1,000 times per second. The result: To anyone on Earth peering through the telescope, the star looks like the single point of light it really is.

“The reason the atmosphere blurs light is that there are tiny changes in temperature as you go from the Earth’s surface up into space. The degree to which air bends light depends on the air’s temperature.

“With adaptive optics systems, telescopes on Earth can see nearly as clearly as those in space.” More at NPR.

Photo: Heidi B. Hammel and Imke de Pater
The near-infrared images of Uranus show the planet as seen without adaptive optics (left) and with the technology turned on (right).

Read Full Post »