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ARRL Propagation Bulletin ARLP042 (2002)

ARLP042 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 42  ARLP042
From Tad Cook, K7VVV
Seattle, WA  October 11, 2002
To all radio amateurs 

ARLP042 Propagation de K7VVV

All indices were up this week. Average daily sunspot numbers rose by
more than 4 and average solar flux was up by nearly 16.  There was a
great deal of geomagnetic activity. The average daily A index was up
over 9 points. There really wasn't a day this week that geomagnetic
indices didn't indicate storminess. The most active day was October
4 when the planetary A index was 48.

The calendar quarter ended a week and a half ago, so it is time to
review some of the averages. Average daily sunspot numbers for the
past seven quarters was 147.3, 164.8, 170.4, 198.1, 178.3, 165.3 and
193.5. Average daily solar flux for those same quarters was 164.4,
166.7, 175.5, 219.1, 203.9, 156.4 and 178.1. Average daily sunspot
numbers for the months January through September were 189, 194.5,
153.1, 144.4, 204.1, 146, 183.5, 191 and 206.4.

Average solar flux for those same months was 227.3, 205, 179.5,
141.1, 178.4, 148.7, 174.4, 183.9 and 175.8. Although we passed the
peak of this cycle some time back, the recent numbers look pretty
high. This should be a good season for DX.

There is a new book out which should be of interest to the people
who read this bulletin. "Storms from the Sun; The Emerging Science of
Space Weather," by Carlowicz and Lopez is full of fascinating details
on recent developments in understanding space weather. It is
published by Joseph Henry Press, operated by the National Academy of

Over the next few days look for the geomagnetic indices to quiet and
solar flux to rise slightly to 175.

Sunspot numbers for October 3 through 9 were 81, 98, 155, 126, 143,
128, and 226, with a mean of 136.7. 10.7 cm flux was 145.9, 157.5,
155.1, 161.7, 163.8, 165.4, and 167.2, with a mean of 159.1.
Estimated planetary A indices were 33, 48, 29, 19, 39, 34, and 22,
with a mean of 32.


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