Radiation clouds at aviation altitudes 

Posted: January 22, 2017 by oldbrew in atmosphere, Clouds, research

Credit: airbus.com

Credit: airbus.com

The observed radiation surges seem to occur ‘at relatively high latitudes, well above 50 degrees in both hemispheres’. They suspect certain magnetic phenomena could be at work. Korean researchers may have found something similar occurring at middle latitudes.

A new study published in the peer-reviewed journal Space Weather reports the discovery of radiation “clouds” at aviation altitudes. When airplanes fly through these clouds, dose rates of cosmic radiation normally absorbed by air travelers can double or more, reports Spaceweather.com.

“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.”

The fact that air travelers absorb radiation is not news. Researchers have long known that cosmic rays crashing into Earth’s atmosphere create a spray of secondary particles such as neutrons, protons, electrons, X-rays and gamma-rays that penetrate aircraft. 100,000 mile frequent flyers absorb as much radiation as 20 chest X-rays—and even a single flight across the USA can expose a traveler to more radiation than a dental X-ray.

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.

The report continues here.

  1. oldbrew says:

    The authors note that instrument readings can sometimes be misleading:

    ‘There is a location at Los Angeles International Airport (LAX) where the primary author can sit at a terminal café prior to boarding a flight and repeatedly measure unusually high dose rates while less than 100 m above sea level. Additionally, on some research aircraft during take-off the ARMAS instrument can see abnormally high dose rates.’


    Mobile phones, internet devices?

  2. Sphene says:


    “…the primary author can sit at a terminal café prior to boarding a flight and repeatedly measure unusually high dose rates while less than 100 m above sea level.”

    Hmm, that sounds like there may be poorly shielded xray machines in the baggage handling area below the main terminal floor.

    [reply] if so they need to get that fixed 😦

  3. jim says:

    They haven’t figured out that ionized radiation will clump? I seem to remember from the mid 60’s, while in the military, reading this in their training materials. But was expressed as at ground level. And returning aircraft for decontamination, where they would need extra attention. Even civilian aircraft were mentioned, as there were emitter areas on them also. Unique.

  4. Tim Hammond says:

    264 flights, and 6 occasions on a flight they got an anomalous reading.

    I suggest the instrument isn’t perfect?

  5. erl happ says:

    Ionisation of the air facilitates the production of ozone. Ozone proliferates in winter in high latitudes. The ozone content of the upper air is intimately associated with surface pressure, geopotential height, the movement of the air at all elevations, the generation of polar cyclones aloft and therefore the position of the Jet Stream.The position of the jet stream in the latitudes where it is found determines whether surface air originates in low latitudes or high latitudes and therefore surface air temperature.

    All of the modern warming has occurred in winter, The extent of the warming increases with latitude.The year to year variability in surface air temperature at all latitudes in the northern hemisphere is greatest in the months of January and February. The variability in the summer months is tiny by comparison.

    In the Southern hemisphere taken as a whole there has been no warming in the month of December for seven decades. If Carbon Dioxide back radiation were to be at all responsible for surface air temperature then the month of December could not avoid warming under a regime of increasing proportions of this trace gas.

    It is not credible that the increased ozone in the winter hemisphere is a product of transfer from the zone of relatively intense ionisation by ultraviolet light emanating from the sun and affecting in the main the summer hemisphere.

    When the sun is quiet the impact of cosmic rays increases. The impact on the behaviour of the atmosphere is per agency of ozone, a potent absorber of long wave radiation from the Earth that is available day and night. For this reason wind speed is observed to increase from the surface to about 150 to 50 hPa in elevation, the jet stream altitudes.

  6. Curious George says:

    The radiation coming from the Sun varies wildly – think of geomagnetic storms and auroras. Unless they compensate for changes in solar activity, their results are meaningless.

  7. oldbrew says:

    Erl Happ says: ‘All of the modern warming has occurred in winter, The extent of the warming increases with latitude.’

    Playing devil’s advocate – wouldn’t that correlate quite well with ‘urban heat islands’ which obviously are a modern phenomenon?

  8. gymnosperm says:

    Erl, it would be very interesting if “all modern warming has occurred in winter”. I just ran hadcrut4 January vs July. While they are out of phase as often as not, they both show the same rough warming trend.

    If you have data supporting winter warming, I would be very interested to see it.

  9. […] Source: Radiation clouds at aviation altitudes  | Tallbloke’s Talkshop […]

  10. gymno, this was part of an argument the mainstream made. For instance a page in John Cook’s site, includes this 2010 graph:

    while the data I guess is pretty much correct, I am not sure of Cook’s argument… I think he assumes heat loss is linear, which it is not. Note that even if a place is getting hotter as a day warms, it is still radiating away heat the entire time. At any given moment (measured in Kelvin) let’s say A is .2% hotter than B, it A will lose > .2% heat per unit of time.

    thus in any (>=decadal) warming trend *for any reason*, the summer days will radiate heat away faster than a winter days will.

    thus the winters will ‘warm faster’. if you think only in terms of photons

    at least that is how it seems to me… Cook says they are warming faster because of GHGs, but maybe thermodynamics explains differently

    ditto for night vs day.

    I am really not sure. ready to be wrong

  11. erl happ says:

    Gymnosperm. To answer your question see : https://reality348.wordpress.com/2016/01/15/8-volatility-in-temperature/

    Data from https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

    Don’t look at the globe as a whole but at specific latitudes. Both hemispheres warm predominantly in winter but the low latitudes of the southern hemisphere warm in summer, driven by Arctic stratospheric processes.

    Atmospheric processes and surface temperature is driven by polar processes. If one examines just the globe as a whole these complexities disappear.

  12. erl happ says:

    If I were revising that chapter today I would be emphasising the role of cosmic rays in ionising the winter atmosphere and enabling the generation of ozone.

  13. RoswellJohn says:

    While there have been ground level enhancements (GLE) from Solar Cosmic Ray (see this report: http://www.ann-geophys.net/23/2281/2005/angeo-23-2281-2005.pdf and http://www.stce.be/esww10/sessions/13cosmicraydetectors.php), there are events that don’t reach that intensity, but could affect the upper atmosphere. Neutrons, muons and probably other particles can be present. Also gamma ray bursts happen at the top of thunderclouds with probable acceleration of other particles. And the direction of the earth’s electric field can accelerate or decelerate any solar cosmic ray particles present. Lots of research being done in this field. I worked on solar cosmic rays in the 60s in the Antarctic and Arctic using riometers to measure ionospheric absorption of cosmic radio waves in the ionosphere as solar cosmic rays hit the earth. The ionosphere is much higher than NASA is talking about in this report, but the higher the energy of the particles the further down they go. And neutrons and muons can reach the ground. And all this stuff is variable so the fact that NASA only measured these a small percentage of the time doesn’t mean the detector is bad.