COMMENTS ON THIS ISSUE FROM PHIL WILKINSON

This Bulletin starts out on a low note for me. A friend of many years, Harvey Cummack, passed away just over a year ago. For almost thirty years I enjoyed Harvey's special kind of humour and philosophy as he explained his discoveries in modelling the ionosphere and ionograms while not losing sight of the more important things in his life. I am glad of the time we had together and would have liked a bit more.

Publication Details: G5 Proceedings

Papers that have been accepted for publication in the G5 Proceedings will appear in a UAG report that should appear later this year, or early next year. It will be about the same length as UAG-103, which appeared after the last URSI meeting. The main details follow.

TITLE: Computer Aided Processing of Ionograms and Ionosonde Records.
EDITOR: P. J. Wilkinson;
PUBLICATION: possibly May 1998

Characteristics Scaled from Ionograms

At the Kyoto URSI General Assembly INAG Meeting, the problem of insufficient characteristics for recording data was raised. During the last triennium, a survey was made of the current characteristics and it was evident that there was no likelihood of recycling old ones. To solve this, we propose broadening the characteristics to include alphabetic, as well as numerical, symbols. A list demonstrating some new characteristics in given in the CHARS article later in this bulletin.

Data Availability

In the Lille report, I indicated that the WDC-A for STP was having difficulty obtaining current, and archive data from groups. Since the meeting, WDC-A now has obtained all the British data. However, French and Australian data are still not reaching the WDC. I hope this situation can improve further over the next year.

Professor Rishbeth raises a more serious issue regarding data availability. Somehow, scientific data has managed to come under the ambit of an effort to design legislation to prevent piracy of a wide range of computer software, including pre-recorded compact disk and cassette music. Unfortunately, by the time you read this, the decisions will probably have been made. While there may be commercial value in preventing the free distribution of data, I can see no legitimate scientific reason to support such legislation. Read this article carefully.

Leonid Meteor Shower

Bill Wright reminded some of us of the forthcoming Leonid meteor shower in November. Every 33 years, this annual meteor shower can reach meteor storm levels with visual meteor rates as high as 150,000 per hour. The next peak is predicted to occur in 1998 or maybe 1999, although there are good reasons for thinking no storm will be seen. An increase in meteor rates is expected in the years leading up to the storm year. During the 1966 storm, Bill reckoned he could see 100 visible trails at any instant. Although meteor rates were not high this year, it will still be worth watching out for this shower over the next two years, just in case. There are two articles in Sky and Telescope (November 1995, p24, November 1996, p74).

In addition, it is possible to observe the ionised meteor trail with an ionosonde, provided the ionosonde is sensitive enough and the ionogram is recorded in a short enough time interval (typically, within 10 seconds). Without careful calibration ionosondes are unlikely to offer good support for meteor science. However, during a major meteor storm they may recover enough data to be useful. This is a prospect worth further considering over the next year. Those interested in looking at some radio meteor results off the Web can go to http://allserv.rug.ac.be/~hdejongh/astro/meteor/meteor.html and successive pages. The University of Ghent radar displays its observations directly to the Web.

Web comments

http://www.ips.gov.au/INAG This is the INAG Homepage that I have just created. Over the next two months, I intend adding items to it. I have material from past INAG Bulletins as well as the UAG Series articles and other assorted information. If you have addresses you feel might be interesting, notes you would like to see here, please e-mail them to me at phil@ips.gov.au. Anybody who has a site they want referred to, or a favourite list of sites they find useful, please send me the information so I can collect then at our site.

There is good ionospheric information at a number of sites on the Web. If you are unfamiliar with the possibilities, a good start point is SPIDR. The Homepage is: http://www.ngdc.noaa.gov/ This is the interactive data request and viewing platform for WDC-A for STP, in Boulder, USA. A wide range of ionospheric data, as well as other data sets, is available at this address. For instance, the Web can reach ionosonde stations. In most cases near real time, data are available. Try http://www.noaa.gov/stp/IONO/grams.html, the SPIDR URL, for the links. Stations where there are digisondes are also available at: http://ulcar.uml.edu/framesd.htm.

The Japanese ionosonde stations are another good example. Go to http://wdc-c2.crl.go.jp The Homepage for the Communication Research Laboratories WDC-C2 for the Ionosphere. When you first log on you will find yourself on the Japanese page. Click on the English version, and then pass on to the "Ionospheric Sounding Data in Japan". There is a choice of ionograms and ionogram surveys and some nice data displays, including mpeg movies for November and December, 1997. All displays are current.

Some other ionosonde sites are:

http://www.irf.se/~ionogram/ where ionograms from Kiruna and Uppsala are displayed as movies and scaled data are presented in tables. You need to explore a little to find everything.

http://www.ips.gov.au/asfc/aus_hf/ion_cat.html is the IPS site for Australian real time ionosonde data. You will find the latest real time ionograms, as well as a catalogue of past hourly ionograms, for Hobart, Canberra, Sydney (also called Camden), Brisbane, Townsville, Darwin and, care of the University of Canterbury, Christchurch in New Zealand.

At http://www.ips.gov.au/asfc/aus_hf/index.html you can view the IPS real time propagation page. Here ionospheric maps based on the scaled ionospheric data are presented. This gives you some idea of how real time ionospheric data can be used.

There are many other sites. I hope this short list and brief comments will encourage you to send in further information. I am especially interested to hear of more ionosonde sites on the Web.

News from South Africa

Lee-Anne McKinnell (phlw@giraffe.ru.ac.za) offered the following comments:

"There is now a digisonde at Grahamstown and the data from the digisonde is available via anonymous ftp from our ionosonde server. The address is: ionosond.ru.ac.za

Our institute (Hermann Ohlthaver Institute for Aeronomy) also has a web page address now. The address is: http://phlinux.ru.ac.za/hoia/ ."

Computer scaling comparison

If computer data proves reliable, then it will gradually replace manually scaled data as the primary data source. However, to date, there has been no substantial effort to identify and quantify the types of errors we should expect in computer generated data. Some individual scaling program errors have been reported, but there has been no attempt to quantify the likely errors from an ensemble of scaling programs. How good, or bad, can these programs be. Are there typical errors? Will knowledge of the likely errors enable us to define better operational methods? I think that the computer data is suitable for some purposes now, but it is not useful for research purposes and therefore unsuitable for archiving unqualified. That is why we have introduced the / scaling letter (see Reinisch this issue and INAG-58).

I now feel we need to go one step further with data comparisons. We need to compare the differences between the many scaling systems. This will give us some measure of the errors and types of error that are could become part of our data sets. It might focus effort, it could act as a warning and it will certainly help define our future resources. It may, for instance, help us construct suitable arguments for more manual scaling.

I want to involve as many groups as possible scaling a selected set of ionograms. The main problem to overcome is that the different scaling methods often also use different ionogram formats. IPS is currently trying to solve this problem using a set of ionograms supplied by Tom Berkey. We plan to take a selection of mid-latitude dynasonde ionograms and construct other ionograms using the ionogram formats we are aware of to date. We will then make a CD-ROM of all the different ionogram formats and offer this to people to scale the ionograms. Requesting a copy of the CD-ROM means you will return your scaled values to me for comparisons.

At this stage, I am inviting anybody who is interested in participating in the exercise to contact me and register interest. I will look forward to hearing from you

New Address for IPS