ZCZC AP05
QST de W1AW
Propagation Forecast Bulletin 5 ARLP005
>From Tad Cook, K7VVV
Seattle, WA January 30, 1998
To all radio amateurs
SB PROP ARL ARLP005
ARLP005 Propagation de K7VVV
Solar activity increased this week over last, but not by much. Average sunspot numbers were up by 17 points, and average solar flux was also higher, but by less than five points. Average solar flux for the previous 90 days rose from 96 to 97, and the daily flux was above the average for that day on five out of seven days. This indicates a moderate general upward trend in solar flux values.
Solar flux peaked at 108.3 on Sunday, but is now headed down to the low nineties. For January 30 through February 1 flux values are projected at 94, 93 and 91. A Coronal Mass Ejection earlier on January 25 should cause unsettled conditions on the last two days of January, but the A index is only expected to rise to around 20. This is enough though to cause problems over polar radio paths and in higher latitudes. Solar flux is expected to bottom out around 90 between February 5-9, then rise up near 100 again later in the month.
Sunspot Numbers for January 22 through 28 were 37, 57, 88, 104, 99, 98 and 89 with a mean of 81.7. 10.7 cm flux was 93, 96.9, 97.5, 108.3, 100, 100.8 and 96.6, with a mean of 99, and estimated planetary A indices were 4, 3, 4, 9, 3, 6, and 2, with a mean of 4.4.
The January, 1998 issue of Scientific American has an interesting article on the Ulysses mission, which is returning new data on high latitude solar magnetic fields. NASA has a web site for this mission at http://ulysses.jpl.nasa.gov/.
Another NASA project of interest to solar observers is the Advanced Composition Explorer (ACE), launched last summer. The February, 1998 issue of Monitoring Times magazine has an informative article on solar weather and the ACE mission. The Goddard Space Flight Center ACE web site is at http://www.gsfc.nasa.gov/ace/ace.html.