Wednesday, July 17, 2019

British Physicist and Radio Amateur Revolutionizes How We See the Ionosphere

The American Radio Relay League relayed the news this week that British Physicist Cathryn Mitchell, whom the ARRL says is known to fellow hams as M0IBG, was awarded the 2019 Edward Appleton Medal and Prize.  Her work sounds fascinating to me and I had to dig a little further.
Mitchell innovated a completely new Earth observation technique by adapting medical tomography to image the Earth's ionosphere, thus revealing the dynamics of the near-Earth space environment. Her use of Global Positioning System satellite signals as a source for space weather tomography, through a new time-dependent mathematical inversion algorithm, has given us the first global-scale view of the ionosphere in response to space weather storms.

Mitchell's research has fundamentally changed our understanding of the Earth's ionosphere, revealing dynamic processes driven by magnetospheric electric fields causing enormous plasma enhancements and uplifts and has led on to ionospheric data assimilation and forecasting.
The method is referred to as CIT, Computerized Ionospheric Tomography.  Perhaps you've had a CAT scan, now more commonly called a CT scan.  In the first case Computerized Axial Tomography, and in the second, Computerized Tomography.  

Naturally, I went in search of some images based on this new technique; which isn't that new, but that I hadn't heard of.  Nature had an article re-evaluating the ionospheric electron density during an ionospheric storm on August 5 and 6, 2011 using the technique and existing data. This is a reconstruction of the data by time (left to right then top to bottom), altitude and geographic coordinates. 

I'd love to see animated 3D graphics of the ionosphere showing these electron densities, varying over time and reconstructed into continuous vertical clouds. 

I've been interested in the ionosphere since I first learned about it back when I was 12 or 13, so naturally this got my attention.  I thought some of you might it interesting, too.  Note at the end of writing this piece, I thought it would be a good idea to check the callsign.  While she isn't listed on or any of the call lookups I can find, there is a reference to her on the Radio Society of Great Britain's Propagation Studies Committee with that call and a article by her.  The QRZ omission is probably an error in the license database.


  1. I will have to dig into that also. I wonder what the scope/area of a view is? I wonder how fast they can be generated? It might provide for some interesting near real time propagation information.


    1. WD5HHH: I'm sorry, I had to laugh when I did your call in CW and I pictured my Honda with an open door 'cause of the door dinger thing.

    2. Thanks Robert. I love it for that. Nineteen (19) dits in a row. I don't know if they have changed the rules for vanity call signs; if so, one could get WH5HHH to have the winner at 21 dits. I have probably thought about this too much.

  2. Damn! I had this idea back in 1989, but Boeing wasn't interested in pursuing it. CT algorithms can be used in many fields, but are not.

    Glad to see it worked.

  3. I'm not sure that every country is as emphatic about mandating that callsign info be public.

    There was a time when I had my callsign tied to a rented mailbox in a neighboring city because there were people I didn't want to be able to look up my address with a web search. I almost dropped my license, and the folks at ARRL, QRZ etc. were completely unfeeling/unsympathetic/stupid about the idea of stalkers, enemies etc.

    What made sense in 1938 - in terms of licensee info in the public domain - might not make sense in 1998 or 2008.

    1. You raise an excellent point, Deb. In the early to mid 80s, when 2m FM and repeaters seemed to reach peak popularity, I'd hear guys telling each other "I'm going on vacation next week" and I'd cringe. Any thug could end up with a scanner and be listening. He knows that house will be empty next week.

      It was different when someone had to have a physical callbook and then look up a callsign was a bit different. That's the part that the thug might not do. In this age of linked databases, given a callsign, I'm sure that we could have a picture of someone's house with a couple of web searches.

      It's different with fellow hams than with the general public.

    2. I am not really worried associating my pseudonym and call sign here in this context. I do not advertise what I am doing in advance. The data about me at the FCC is easy to get even if the ARRL and QRZ didn't have it; they are just mirroring the FCC. There are dangers is this connected world but there have always been those who might do you harm. It is just not as localized as it was.

    3. I hope it didn't come across as critical of you - it wasn't intended to be. You're a grownup and can make those decisions.

      On a typical day, I bet I see a couple of dozen call signs spread around the various places I read. Lots of hams use them as a unique name online.

    4. SiG, I did not take yours as critical of me. I was always bothered by people on the repeaters in DFW saying they were going on vacation. I would tell people what I did on vacation after the fact.

      With the way it is on ARRL and QRZ and maybe some other sites that mirror the FCC, a call sign is now a pseudonym.

  4. 2am two days ago: "Dad, if I run 50 feet of speaker wire I can get a LOT of stations."

    Today: "Dad, how could I get a 200' tower up?"

    I anticipate he'll have a ham license before Christmas.

  5. BillB:
    I'm too lazy to figure out which country you would have to move to, but ... doggone it, now I wanna know myself. BRB. OK, to maximize your "dit count" you need to move to: Haiti HHA-HHZ, Sweden SAA-SMZ, Egypt SSA-SSM, Sudan SSN-STZ. I think you should go for HH5HHH but look out for quakes and tsunamis.