Propagation News – 9 June 2013

| June 7, 2013

And now the solar factual data for the period from Friday the 31st of May to Thursday the 6th of June, compiled by Neil Clarke, G0CAS on Friday the 7th of June.

Up to six sunspot groups were visible, most were small and quiet. Solar activity was mostly low but on the 31st and the 5th solar activity increased to moderate levels when a single M class solar flare took place on each day. Associated coronal mass ejections and sudden ionospheric disturbances took place with these flares. Solar flux levels increased slightly from 102 units on the 31st to 112 by the 3rd. The average was 108 units. The 90 day solar flux average on the 6th was 122 units, that’s one down on last week. X-ray flux showed little daily variation and averaged B2.5 units. Geomagnetic activity started at quiet levels on the 31st but by midnight a geomagnetic disturbance started and lasted for the next two days. The Ap index on the 1st was 58 units and 22 on the 2nd. This was due to a recurring coronal hole. Activity then declined to quiet levels till the 6th, when a glancing blow arrived from a coronal mass ejection that departed the Sun on the 3rd. The Ap index on the 6th was 21 units. The average was Ap 19 units. Solar wind data from the ACE spacecraft saw solar wind speeds increase from 320 kilometres per second on the 31st to 820 by the 2nd. Speeds then declined to 450 kilometres per second by the 4th and the 5th. Particle densities were high at first with 48 and 30 particles per cubic centimetre measured on the 31st and the 1st respectively. Densities then declined to low for the remainder of the period. Bz varied between minus 21 and plus 18 nanoTeslas during the most disturbed day and between minus and plus 3 nanoTeslas on the quietest day.

And finally the solar forecast for the coming week. This week solar activity is expected to continue at low levels with just the occasional chance of a larger solar flare taking place. Solar flux levels are expected to be around the 110 mark for most of the week, however, a slight increase could take place towards next weekend. Geomagnetic activity is expected to be most quiet except for a small coronal hole disturbance that could be still taking place today. MUFs during daylight hours at equal latitudes should be around 22MHz for the south and 19MHz for the north. Darkness hour lows should be around 14MHz. Paths this week to the Middle East should have a maximum usable frequency with a 50 per cent success rate of around 22MHz. The optimum working frequency with a 90 per cent success rate will be about 17MHz. The best time to try this path will be between 1400 and 2000 hours. Also, this path could be open via double-hop sporadic-E on 50MHz during any larger openings.

And that’s all for this week from the propagation team.

Category: GB2RS Propagation News

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