Radio waves carry news of climate change

July 30, 2013, Tel Aviv University
Radio waves carry news of climate change

The ionosphere, one of the regions of the upper atmosphere, plays an important role in global communications. Ionized by solar radiation, this electricity-rich region is used for the transmission of long wave communications, such as radio waves. Now Prof. Colin Price of Tel Aviv University's Department of Geophysical, Atmospheric and Planetary Sciences, working alongside PhD candidate Israel Silber, has discovered that the radio waves reflecting back to Earth from the ionosphere offer valuable news on climate change as well.

Their research shows that the strength of on the ground is a reliable indicator of temperature change above. Prof. Price and his team used simple radio antennae on the ground to measure radio waves broadcast by navigational transmitters around the globe, then compared information on the strength of these radio signals with data on in the upper atmosphere. They discovered that climate change in the upper atmosphere—caused by an abundance of —may lead to a greater absorption of radio waves. Weaker signals could therefore be indicative of greater climate change.

Detailed in the Journal of Geophysical Research, this simple, cost-effective measurement can be a valuable contribution to the ongoing effort to track climate change, says Prof. Price, adding to measurements of ground and lower atmospheric temperatures to create a more holistic picture.

Global warming, upper atmospheric cooling

On the Earth's surface and in the lower atmosphere, an increase of greenhouse gases has a warming effect, the gases acting as a "blanket" and keeping heat from escaping from the Earth into space. But these gases, including carbon dioxide, are increasing in the upper atmosphere as well, where they have a cooling effect.

When cooled, the ionosphere contracts and descends into the atmosphere to where air is denser – leading to a higher absorption of radio waves, Prof. Price explains. By examining satellite-gathered data on the temperature in the upper atmosphere and comparing results to measurements of radio wave amplitudes collected on the ground, the researchers were able to uncover a clear correlation, consistent over time. As the upper atmosphere gets colder, radio signals lose their strength.

While the sun is certainly the driving force behind changes in temperature in this region, it accounts for only 60 to 70 percent of temperature variations, says Prof. Price. The remaining variability could not be systematically measured until now. By adding measurements of taken on the ground to estimates, researchers can now explain approximately 95 percent of temperature changes in the upper atmosphere.

Degrees of change

According to Prof. Price, this new technique will be a valuable addition to current methods of monitoring , such as the measurement of ground temperatures. Without the need for expensive equipment like satellites, monitoring the upper atmosphere can be done inexpensively and continuously. And because temperatures in the upper atmosphere fluctuate more dramatically than those on the ground—for every one degree of warming in the lower atmosphere, there is a corresponding ten degree cooling in the upper atmosphere—changes are far easier to monitor.

Using this system might reveal more about the ionosphere than ever before. The region is notoriously difficult to monitor; there are no weather balloons or airplanes that can go high enough, and it is too low for orbiting satellites. But with this method, it could be possible to study long and short term changes in the , such as the impact of solar storms or thunderstorms on the .

Explore further: Error sought & found: State-of-the-art measurement technique optimised

Related Stories

Sounding rocket to observe currents in atmosphere

June 20, 2013

Swirling through Earth's upper atmosphere is a layer of charged particles called the ionosphere. Constantly on the move, currents through the ionosphere can be much more complicated than winds at lower altitudes, because ...

Lightning strokes can probe the ionosphere

April 12, 2013

(Phys.org) —Thunderstorms, and the resulting partially ionized plasma of the ionosphere, can distort radio signals traveling to satellites important to communications, navigation or national security

Recommended for you

Oceans of garbage prompt war on plastics

December 15, 2018

Faced with images of turtles smothered by plastic bags, beaches carpeted with garbage and islands of trash floating in the oceans, environmentalists say the world is waking up to the need to tackle plastic pollution at the ...

A damming trend

December 14, 2018

Hundreds of dams are being proposed for Mekong River basin in Southeast Asia. The negative social and environmental consequences—affecting everything from food security to the environment—greatly outweigh the positive ...

Data from Kilauea suggests the eruption was unprecedented

December 14, 2018

A very large team of researchers from multiple institutions in the U.S. has concluded that the Kilauea volcanic eruption that occurred over this past summer represented an unprecedented volcanic event. In their paper published ...

The long dry: global water supplies are shrinking

December 13, 2018

A global study has found a paradox: our water supplies are shrinking at the same time as climate change is generating more intense rain. And the culprit is the drying of soils, say researchers, pointing to a world where drought-like ...

Death near the shoreline, not life on land

December 13, 2018

Our understanding of when the very first animals started living on land is helped by identifying trace fossils—the tracks and trails left by ancient animals—in sedimentary rocks that were deposited on the continents.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1 / 5 (7) Jul 30, 2013
By adding measurements of radio waves taken on the ground to solar radiation estimates, researchers can now explain approximately 95 percent of temperature changes in the upper atmosphere.

Sounds great, but..., as has been pointed out repeatedly, they use outdated and incorrect models to explain the solar wind and it's interaction with Earth's EM field. Also, according to several posters here who believe their opinion is worth something claim the temp of the ionosphere is meaningless, swift.

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.