Solar Terrestrial Activity Report [Image] Last update August 27, 2000 at 05:50 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 unsettled on August 26. Solar wind speed ranged between 367 and 416 km/sec. Solar flare activity was low. Solar flux was 137.0, the planetary A index was 9 (3-hour K indices: 1232 3331, Boulder K indices: 1222 1211). Region 9138 was quiet and stable. Region 9139 decayed slowly and was quiet. Region 9140 was mostly unchanged and quiet. Region 9142 was quiet and stable. Region 9143 could produce occasional C flares and possibly another minor M flare. Region 9144 continued to develop quickly and should produce C flares and may be capable of minor M class flaring. Flares and CMEs A total of 4 C class events were recorded on August 26. Region 9144 produced several sub flares as well as a C3.8/1N flare at 22:16 UTC. A filament eruption was observed in the southeast quadrant 10.15 degrees east of the central meridian starting at 11:25 UTC. No obvious CME was observed. The background x-ray flux is at the class B7 level. Coronal holes A coronal hole in the northern hemisphere will rotate into a geoeffective position on August 27. Forecast The geomagnetic field is expected to be quiet to unsettled August 27-29. On August 28 there is a possibility of minor geomagnetic effects (causing isolated unsettled to active intervals) from the partial halo CME observed on August 25. A coronal stream could cause unsettled to active conditions on August 30. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is 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 N24W45 plage 9138 20000819 1 S31W24 0040 HSX 9139 20000820 4 S09W59 0110 CAO 9140 20000822 9 N09E12 0030 CRO 9141 20000823 N16W47 plage 9142 20000824 1 N15E47 0050 HSX 9143 20000824 9 S19E46 0180 DSO 9144 20000825 20 N25E02 0140 DAI Total number of sunspots: 44 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 2000.08 163.6 (1) 138.7 (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]