Wednesday, 18 March 2015

Aurora finale & propagation predictions?

Well, it is the day after St Patricks Day.

The GOES magnetometer graph of the event is shown, thanks to the Solarham page. The scale has had to be lengthened, as usually it does not extend much beyond the bottom of the daily sine-wave type variations. you can see that the magnetic fields were heavily disturbed.

The second phase of the 17 March event went on after midnight, but I finally ran out of reserves about 23:30. After that US and Canadian amateurs did good work all night. I did manage to work a couple more stations, G4ASR and G4RGK before pulling the big switch at 23:44. The beacons in GI were still coming in and I could hear traces of signals on the calling frequencies, but I was, basically, banjaxed.

At about16:00 the next day the HF bands are still battered after the shock. My favourite 10m has been fairly well closed all the past 24 hours. It will return eventually. There have been a few more auroral contacts in Europe this afternoon but I suspect this one is now over.

OK, I have to say that a successful aurora for me usually invovles five or six stations. Typically that is a couple of GMs and maybe an LA or an OZ. Sometimes something exotic like Faeroes Islands or Jan Mayen spice it all up a bit. So the St Patrick's Day event 2015, with 45 stations worked, is a big deal. Even then I am not entirely happy. If I had been able to use 6 metres I may have joined in a trans-Atlantic opening (though that seemed further South). The stations I did work were not very evenly distributed, with a lot of G stations, several EIs, OZs and PAs. That pattern was actually quite localised. There were no OHs, DKs or SPs heard here. I cannot complain though.

The question arises, can these events not be more accurately predicted? Frankly I would say "no". I know that there are all sorts of predictions published, but they never seem to me to be able to avoid giving many "false positives". In other words, they warn you of things which do not happen.

Other predictions (and I will not say whose, but they call themselves a National Radio Society) are so bland as to be useless. "It is not Summer yet so don't expect Sporadic E" (obvious, and occasionally wrong too), "There are no meteor showers predicted, so you could use random metor scatter instead" (duh!), and "the weather looks good so maybe there will be some tropo" (yeah, like you care about the weather where I am ). If those are predictions, I could do without them.

I do my own predictions. I watch Solarham (I will post a link to the site address alongside this post). Then I look at what is predicted there, interpret it my own way, and act accordingly. And I too get a lot of "false positives". But I was ready for this CME and aurora so I am happy enough.

Solarham do not predict radio events. They describe the solar situation, and you have to work out the radio effects yourself. Fair enough, I like to use my brain. This is a scientific hobby after all. But if the great US agencies like NASA and NOAA get caught on the hop by the St Patrick's Day event (they predicted a "possible glancing blow"), then my little string of seaweed can hardly predict the weather. I believe that nobody can predict the random events on a complex system like the Sun, and then accurately transfer the likely effects across space to Ayton, Berwickshire.

When is a "false positive" OK? When it is MY "false positive". That way I only have myself to blame.



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