Solar Terrestrial Activity Report [Image] Last update August 29, 2000 at 04:45 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update August 4, 2000)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update August 4, 2000)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update August 4, 2000)] [Historical solar and geomagnetic data charts 1954-2000 (last update August 10, 2000)] Recent development The geomagnetic field was quiet to minor storm on August 28. Solar wind speed ranged between 392 and 603 km/sec. A coronal stream based disturbance began at ACE at 06:10 UTC with solar wind speed increasing gradually for several hours after that. The source of the coronal stream is likely a fairly narrow and long coronal hole which begins in the southwest quadrant and snakes in an ENE direction into the northeast quadrant. Solar flare activity was low. Solar flux was 160.0, the planetary A index was 21 (3-hour K indices: 2224 4445, Boulder K indices: 2223 4443). Region 9138 was quiet and stable. Region 9139 was quiet and is rotating off the visible disk. Region 9140 developed slowly and was quiet, C flares are possible, as may a minor M class flare be. Region 9142 was quiet and stable. Region 9143 developed slowly and could produce C and occasional minor M class flares. Region 9144 was mostly unchanged and has C and minor M class flaring potential. Region 9145 developed slowly and could produce C flares. Region 9146 decayed into spotless plage. New region 9147 rotated into view at the northeast limb. New region 9148 emerged in the southeast quadrant. New region 9149 rotated partly into view at the northeast limb, the region could be capable of M class flaring. Flares and CMEs A total of 4 C class events were recorded on August 28. Region 9143 produced a C1.1 flare at 11:42, a C2.2 flare at 13:24, a C1.7 flare at 16:36 and a C3.3/1N flare at 17:04 UTC. The latter flare was associated with a moderate type II sweep and a possible coronal mass ejection. The background x-ray flux is at the class B6 level. Coronal holes A coronal hole in the northern hemisphere was in a geoeffective position on August 27-28. Forecast The geomagnetic field is expected to be unsettled to minor storm on August 29 and quiet to active on August 30-31. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very poor. Coronal holes (1) Coronal mass M and X class flares (3) ejections (2) [Coronal hole indicator][CME indicator] [M and X class flare indicator] 1) Effects from a coronal hole could reach earth within the next 5 days. 2) Material from a CME is likely to impact earth within 96 hours. 3) There is a possibility of either M or X class flares within the next 48 hours. Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability. Active solar regions (Recent map) Solar Date Actual no. Location at region numbered sunspots midnight Area Classification Comment 9137 20000819 N24W71 plage 9138 20000819 1 S28W50 0020 HSX 9139 20000820 1 S08W86 0110 HAX 9140 20000822 18 N09W14 0100 DAO 9141 20000823 N16W73 plage 9142 20000824 1 N16E21 0020 HSX 9143 20000824 16 S19E20 0310 EAO beta-gamma 9144 20000825 15 N26W24 0220 EAO 9145 20000827 5 S10E47 0060 DAO 9146 20000827 S26E38 plage 9147 20000828 2 N04E67 0080 HAX 9148 20000828 2 S20E47 0010 BXO 9149 20000828 4 N10E70 0110 CAO beta-gamma Total number of sunspots: 65 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.07 165.6 113.5 94.3 (+1.2) 1999.08 170.7 93.7 97.5 (+3.2) 1999.09 135.7 71.5 102.3 (+4.8) 1999.10 164.8 116.7 107.8 (+5.5) 1999.11 191.5 133.2 110.9 (+3.1) 1999.12 169.8 84.6 111.0 (+0.1) 2000.01 158.1 90.1 112.8 (+1.8) 2000.02 174.1 112.9 (115.7 predicted, +2.9) 2000.03 208.2 138.5 (118.2 predicted, +2.5) 2000.04 184.2 125.3 (120.4 predicted, +2.2) 2000.05 184.9 120.8 (121.2 predicted, +0.8) 2000.06 179.8 124.9 (122.8 predicted, +1.6) 2000.07 202.3 169.1 2000.08 163.0 (1) 148.0 (2) 1) Running average based on the daily 20:00 UTC solar flux value at 2800 MHz. 2) Unofficial, accumulated value. The official value is typically 25-40% less. This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]