The uncertainty of science: Researchers have found evidence that suggests that planes flying at higher latitudes can sometimes fly through concentrated pockets of high cosmic radiation.
“We have flown radiation sensors onboard 264 research flights at altitudes as high as 17.3 km (56,700 ft) from 2013 to 2017,” says Kent Tobiska, lead author of the paper and PI of the NASA-supported program Automated Radiation Measurements for Aerospace Safety (ARMAS). “On at least six occasions, our sensors have recorded surges in ionizing radiation that we interpret as analogous to localized clouds.”
…Conventional wisdom says that dose rates should vary smoothly with latitude and longitude and the height of the aircraft. Any changes as a plane navigates airspace should be gradual. Tobiska and colleagues have found something quite different, however: Sometimes dose rates skyrocket for no apparent reason. “We were quite surprised to see this,” says Tobiska.
All of the surges they observed occurred at relatively high latitudes, well above 50 degrees in both hemispheres. One example offered in their paper is typical: On Oct 3, 2015, an NSF/NCAR research aircraft took off from southern Chile and flew south to measure the thickness of the Antarctic ice shelf. Onboard, the ARMAS flight module recorded a 2x increase in ionizing radiation for about 30 minutes while the plane flew 11 km (36,000 feet) over the Antarctic Peninsula. No solar storm was in progress. The plane did not abruptly change direction or altitude. Nevertheless, the ambient radiation environment changed sharply. Similar episodes have occurred off the coast of Washington state.
The theories proposed to explain this at the link are not very convincing, and suggest to me that they really do not know what causes this. All we do know is that it likely associated with the interaction of the Earth’s magnetic field and cosmic radiation.