Hole in ionosphere is caused by sudden stratospheric warming

August 7, 2018 by Nancy Wolfe Kotary, Massachusetts Institute of Technology
Researchers found that electron density in the nighttime ionosphere (the part of our atmosphere where auroras occur) was dramatically reduced by the effects of sudden stratospheric warming for several days: A significant hole was formed that stretched across hemispheres from latitudes 55 degrees S to 45 degrees N. Credit: NASA/JPL

Forecasting space weather is even more challenging than regular meteorology. The ionosphere—the upper atmospheric layer containing particles charged by solar radiation—affects many of today's vital navigation and communication systems, including GPS mapping apps and airplane navigation tools. Being able to predict activity of the charged electrons in the ionosphere is important to ensure the integrity of satellite-based technologies.

Geospace research has long established that certain changes in the atmosphere are caused by the sun's radiation, through mechanisms including solar wind, geomagnetic storms, and solar flares. Coupling effects—or changes in one atmospheric layer that affect other layers—are more controversial. Debates include the extent of connections between the layers, as well as how far such coupling effects extend, and the details of processes involved with these effects.

One of the more scientifically interesting large-scale atmospheric events is called a sudden stratospheric warming (SSW), in which enormous waves in the troposphere—the lowermost layer of the atmosphere in which we live—propagate upward into the stratosphere. These planetary waves are generated by air moving over geological structures such as large mountain ranges; once in the stratosphere, they interact with the polar jet streams. During a major SSW, temperatures in the stratosphere rise dramatically over the course of a few days.

SSW-induced changes in the ionosphere were once thought to be daytime events. A recent study led by Larisa Goncharenko of MIT Haystack Observatory, available online and in the forthcoming issue of the Journal of Geophysical Research: Space Physics, examined a major SSW from January 2013 and its effect on the nighttime ionosphere. Decades of data from the MIT Millstone Hill geospace facility in Westford, Massachusetts; Arecibo Observatory in Puerto Rico; and the Global Navigation Satellite System (GNSS) was used to measure various parameters in the ionosphere and to separate the of the SSW from other, known effects.

The Millstone Hill incoherent scatter radar facility at MIT Haystack Observatory in Westford, Massachusetts was used in the recent study. Credit: MIT Haystack Observatory

The study found that electron density in the nighttime ionosphere was dramatically reduced by the effects of the SSW for several days: A significant hole was formed that stretched across hemispheres from latitudes 55 degrees S to 45 degrees N. They also measured a strong downward plasma motion and a decrease in ion temperature after the SSW.

"Goncharenko et al. show clearly that lower atmospheric forcing associated to the large meteorological event called an SSW can also influence the low- and mid-latitude ionosphere," says Jorge L. Chau, head of the Radar Remote Sensing Department at the Leibniz Institute of Atmospheric Physics. "In a way the connection was expected, given the strong connectivity between regions; however, due to other competing factors, lack of proper data, and—more important—lack of perseverance to search for such nighttime connections, previous studies have not shown such connections—at least not as clear. The new findings open new challenges as well of opportunities to improve the understanding of lower atmospheric forcing in the ionosphere."

These significant results from Goncharenko and colleagues are also featured as an AGU research highlight in EOS.

Understanding how events far away and in other layers of the atmosphere affect the ionosphere is an important component of space weather forecasting; additional work is needed to pin down the precise mechanisms by which SSWs affect the nighttime ionosphere and other coupling effects.

"The large depletions in the nighttime ionosphere shown in this study are potentially important for near-Earth space weather as they may impact how the upper atmosphere responds to geomagnetic storms and influence the occurrence of ionosphere irregularities," says Nick Pedatella, scientist at the High Altitude Observatory of the National Center for Atmospheric Research. "The observed depletions in the nighttime ionosphere provide another point of reference for testing the fidelity of model simulations of the impact of SSWs on the ."

Explore further: New tool helps minimize impact of solar activity

More information: L. P. Goncharenko et al. Deep Ionospheric Hole Created by Sudden Stratospheric Warming in the Nighttime Ionosphere, Journal of Geophysical Research: Space Physics (2018). DOI: 10.1029/2018JA025541

Related Stories

New tool helps minimize impact of solar activity

April 10, 2018

University of Saskatchewan researcher Lindsay Goodwin has developed a new way to measure the impact of solar activity on the ionosphere as indicated by northern lights and geomagnetic storms. The ionosphere is the upper part ...

Solar eclipse caused bow waves in Earth's atmosphere

January 22, 2018

The celebrated Great American Eclipse of August 2017 crossed the continental U.S. in 90 minutes, and totality lasted no longer than a few minutes at any one location. The event is well in the rear-view mirror now, but scientific ...

Solar storms can drain electrical charge above Earth

April 11, 2017

New research on solar storms finds that they not only can cause regions of excessive electrical charge in the upper atmosphere above Earth's poles, they also can do the exact opposite: cause regions that are nearly depleted ...

Recommended for you

Superflares from young red dwarf stars imperil planets

October 18, 2018

The word "HAZMAT" describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by ...

Blazar's brightness cycle confirmed by NASA's Fermi mission

October 18, 2018

A two-year cycle in the gamma-ray brightness of a blazar, a galaxy powered by a supermassive black hole, has been confirmed by 10 years of observations from NASA's Fermi Gamma-ray Space Telescope. The findings were announced ...

Astronomers catch red dwarf star in a superflare outburst

October 18, 2018

New observations by two Arizona State University astronomers using the Hubble Space Telescope have caught a red dwarf star in a violent outburst, or superflare. The blast of radiation was more powerful than any such outburst ...

Magnetic fields may be the key to black hole activity

October 17, 2018

Collimated jets provide astronomers with some of the most powerful evidence that a supermassive black hole lurks in the heart of most galaxies. Some of these black holes appear to be active, gobbling up material from their ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
2 / 5 (4) Aug 13, 2018
This is likely direct evidence of joule heating of the atmosphere due to effects of the solar wind and spaceweather.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.