Researchers measure variations in atmospheric radiation

Solar flares. Magnetic polar drift. Latitude. Altitude.

These are all things that can affect how much radiation people – and ever-more-sensitive aircraft computers – experience.

Epaminondas Stassinopoulos is an astrophysicist at NASA’s Goddard Space Flight Center in Maryland. Stassinopoulos is the lead researcher of a study to be published this month in Space Weather, a new journal published by the American Geophysical Union.

This study builds on previously collected radiation level data from researchers all over the world – and it adds another dimension: the variations that can result from differences in altitude and latitude, and short-term events like space weather (such as solar flares) and atmospheric weather like tornadoes, hurricanes, and thunderstorms. Radiation levels are also subject to long-term effects resulting from changes in the Earth’s magnetic field and in the solar cycle.

Preliminary radiation data was collected for this study on cargo routes flying across the Atlantic and Pacific Oceans. However, to develop a useful model that could accurately predict global radiation levels, Stassinopoulos says, much more data on radiation levels will be necessary. The study in Space Weather outlines some of the factors that need to be considered, but the bulk of the data-gathering lies ahead.

One solar cycle lasts, on average, ten years.

Such a global radiation map, Stassinopoulos says, could be useful to what he calls “fly-by-wire” aircraft – aircraft that are computer-controlled. This equipment, he says, is highly sensitive to radiation damage. And there is also concern about radiation effects on flight crews, which are consistently exposed to high radiation levels.

To protect equipment, Stassinopoulos says, electronics could be shielded better, or less radiation-sensitive parts could be added. To protect people, he adds, it’s a matter of changing the altitude – or even the route – of the flight.

The Concorde flew at the highest altitude of any aircraft – 60,000 feet – so it was the most exposed to harmful radiation. Most international flights fly at 32 to 40,000 feet. But, Stassinopoulos says, if they were pre-warned about potentially high radiation levels, the airlines could take action.

Another possible step the airlines could take is to change the flight routes. That would help because as you go from polar regions to the equator, the radiation is deflected – less and less particles penetrate the atmosphere. Flying at lower latitudes, therefore, could also help to avoid the worst effects of radiation.