ZCZC AP42
QST de W1AW
Propagation Forecast Bulletin 42 ARLP042
From Tad Cook, K7VVV
Seattle, WA October 11, 2002
To all radio amateurs
SB PROP ARL ARLP042
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 Sciences.
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.