Strange Space Weather Over Africa
Posted by addisethiopia on January 22, 2017
“My people have been lost sheep; their shepherds have led them astray and caused them to roam on the mountains. They wandered over mountain and hill and forgot their own resting place. ” – Jeremiah 50:6
“The shepherds are senseless and do not inquire of the LORD; so they do not prosper and all their flock is scattered. ” – Jeremiah 10:21
“The wind will drive all your shepherds away, and your allies will go into exile. Then you will be ashamed and disgraced because of all your wickedness.” – Jeremiah 22:22
“Woe to the shepherds who are destroying and scattering the sheep of My pasture!” declares the LORD. Therefore thus says the LORD God concerning the shepherds who are tending My people: “You have scattered My flock and driven them away, and have not attended to them; behold, I am about to attend to you for the evil of your deeds,” declares the LORD. – Jeremiah 23:1-2
“My sheep hear my voice, and I know them, and they follow me: And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.” – Jesus in John 10:27
“He that is not with me is against me; and he that gathereth not with me scattereth abroad.” – Jesus in Matthew 12:30
Jesus knew their thoughts and said to them, “Every kingdom divided against itself will be ruined, and every city or household divided against itself will not stand.” – Matthew 12:25
Nov. 13, 2007: Something strange is happening in the atmosphere above Africa and researchers have converged on Addis Ababa, Ethiopia, to discuss the phenomenon. The Africa Space Weather Workshop kicked off Nov. 12th with nearly 100 scientists and students in attendance.
The strange phenomenon that brings all these people together is the ion plume—”a newly discovered form of space weather,” says University of Colorado atmospheric scientist and Workshop co-organizer Tim Fuller-Rowell.
Researchers liken the plumes to smoke billowing out of a factory smokestack—except instead of ordinary ash and dust, ion plumes are made of electrified gas floating so high above ground they come in contact with space itself. “The plumes appear during geomagnetic storms and they can interfere with satellite transmissions, airline navigation and radio communications,” says Fuller-Rowell. Indeed, it is their effect on GPS signals that led to the discovery of plumes over North America just a few years ago.
A typical example is the plume of Nov. 20, 2003:
Above: A plume of excess electron density over North America on Nov. 20, 2003. The plume was discovered and mapped by its effect on GPS signals. Credit: Courtesy of Anthea Coster and John Foster of MIT.
Two days before this map was made, an explosion on the sun had hurled a cloud of magnetized gas—a CME—toward Earth. The plume formed when the CME hit, triggering a strong geomagnetic storm. The plume consists of ionized air at high altitude moving from Florida to Canada at a speed of 1 km/s (2200 mph).
“Okay, now we’ve seen the ‘smoke,’ but where is the smokestack?” asks Fuller-Rowell.
The search is leading researchers to Africa.
“Many believe the source of the plumes is near Earth’s magnetic equator,” explains NASA heliophysicist Lika Guhathakurta who is attending the Workshop. “Africa is a great place to check this possibility because the magnetic equator passes directly over the sub-Sahara.”
Just one problem: “There aren’t enough sensors in Africa to study the phenomenon,” says Fuller-Rowell. The sensor of choice is the dual-frequency GPS receiver. “North America has an abundance of dual frequency GPS receivers—thousands of them in a network we use to monitor North American plumes. But Africa has only a few dozen.”
Below: Dual frequency GPS receivers now in Africa. More are needed to investigate the plume phenomenon.
The purpose of the Workshop is to familiarize African space scientists with the plume phenomenon and lay the groundwork for a continent-wide GPS network. “Within a few years we hope to deploy hundreds of receivers,” he says.
Ion plumes inhabit a layer of Earth’s atmosphere called the “ionosphere.” It is a broad region 85 km to 600 km above ground level where ultraviolet radiation from the sun knocks electrons off atoms and molecules, creating a layer of ionized gas or “plasma” surrounding our entire planet. As ham radio operators have known for more than 100 years, the ionosphere can bend, distort, reflect and even absorb radio waves. Plumes amplify these effects.
How important is Africa to the study of this phenomenon? “Consider the list of organizations who have joined forces to sponsor the Africa Space Weather Workshop: NASA, NOAA, the National Science Foundation, the European Office of Aerospace Research and Development (EOARD), the International Center for Theoretical Physics (ICTP), and many others,” says Guhathakurta. “It’s widely understood that Africa is key to the puzzle.”
At the moment only North America has a well-mapped ionosphere. NOAA posts new images every 15 minutes at this website. “Five years from now,” says Fuller-Rowell, “we hope to be making realtime maps of the ionosphere over Africa, too.”
Africa is plasma incognita—but not for long. Stay tuned!
Saharan Dust From Africa Brings Hazy Skies to Texas Gulf Coast
This Saharan air can also squelch tropical cyclones from forming or may help fizzle them.
A plume of Saharan dust from Africa made it all the way to the Texas Gulf Coast early this week, making for hazy skies as well as vivid sunrises and sunsets.
Yet another plume of dust located over Mexico’s Yucatan Peninsula on Wednesday morning was expected to spread towards the Texas Gulf Coast by Thursday. This may create more hazy conditions late this week, the National Weather Service in Houston said.
Plumes of dust from the Sahara Desert frequently make a 5,000-mile-long voyage to parts of the United States and the air that lofts these particles can have a big impact on the Atlantic hurricane season.
Known as the Saharan air layer (SAL), this dry, dusty air mass pushes westward off Africa into the tropical Atlantic Ocean about every three to five days from late spring through early fall.
“The air is extremely dry, with about one-half the moisture of the typical tropical atmosphere,” said Jason Dunion, a tropical scientist with NOAA’s Hurricane Research Division in an email.
The SAL is typically located between 5,000 and 20,000 feet above the earth’s surface and is transported westward by bursts of strong winds that are located in the central and western Atlantic at altitudes between 6,500 and 14,500 feet.
It’s easy to see on this NASA animation how the large dust plumes spread westward in early-mid July 2016 across the Atlantic, Caribbean and into the western Gulf of Mexico. Dust in the SAL is indicated by the orange and brown contours.
Animation of total aerosol optical thickness from July 4-11, 2016 highlighting the Saharan air layer (SAL) and embedded Saharan dust traversing the Atlantic Ocean basin, shown by the orange and brown contours in the middle of the image loop. (NASA/GSFC)
To give you a sense of how large these SALs are, Dunion says the outbreak pushing off the African coast on July 12, 2016, was roughly the size of the Lower 48 States.
aharan dust tracks as far west as the Caribbean Sea, Florida and the Gulf of Mexico multiple times each year.
The dust particles can contribute to hazy skies, and rather photogenic sunrises and sunsets in the Caribbean islands and near the Gulf Coast. NASA says the dust can also lead to the creation of toxic algal blooms in the Gulf of Mexico.
The dust also reaches South America at times. In fact, a recent study by NASA scientists has found that the dust acts as a fertilizer for the Amazon rainforest.
SAL: Hurricane Squasher
It’s not yet well understood if and how the dust itself plays any significant, direct role on tropical cyclones, according to Dunion.
“Some studies have suggested that it (the dust) can affect how clouds and precipitation actually form.”
An SAL can surround and engulf either an active tropical cyclone or a “wanna-be” tropical disturbance. When that happens, the system is suppressed, according to a 2004 study by Jason Dunion of NOAA-HRD and Christopher Velden of the Univerisity of Wisconsin’s Space Science and Engineering Center.
One such recent example of this was Bertha in early August 2014. While west of the Windward Islands, Bertha was completely surrounded on all sides by an SAL.