Solar Terrestrial Activity Report [Image] Last update September 19, 2002 at 03:15 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update September 3, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 3, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 3, 2002)] [Historical solar and geomagnetic data charts 1954-2002 (last update August 16, 2002)] Recent development The geomagnetic field was quiet to active on September 18. Solar wind speed ranged between 413 and 590 km/sec under the influence of a coronal stream. The source of this coronal stream is probably an extension of the northern polar coronal hole. Solar flare activity was low. Solar flux was 176.8, the planetary A index was 14 (3-hour planetary K indices: 4323 4333, Boulder K indices: 3223 4323). The background x-ray flux is at the class B6 level. Region 10105 continued to decay fairly quickly as it approached the southwest limb. Most of the smaller penumbrae, which had emerged the previous day southeast and northwest of the dominant penumbra, disappeared. Minor M class flares are still possible. Region 10107 decayed slowly and quietly. Region 10110 was visible with a single small spot early in the day before rotating out of view at the northwest limb. Region 10114 decayed slowly as it lost all spots outside of the main penumbra. Region 10115 developed slowly early in the day, then began to decay. By midnight most of the central spots had disappeared. Region 10116 decayed slowly and quietly. Region 10117 was quiet and stable. Region 10119 developed moderately quickly and is currently the largest region on the visible disk. One day ago it appeared as if a magnetic delta structure was forming. This development continued and there is now a delta in the central part of this region. M class flares are possible Region 10120 developed slowly and quietly.. Region 10121 was quiet and stable. Region 10122 was quiet and stable. Region 10123 was quiet and stable. New region 10124 emerged during the latter half of September 17 in the northwest quadrant and was noticed by SEC/NOAA on Sept.18. New region 10125 rotated into view at the southeast limb. SEC/NOAA failed to notice a new region which emerged northeast of region 10123 and was located at S14E19 at midnight. Flares and CMEs A total of 10 C class events was recorded on September 18. Region 10105 produced a C3.8 flare at 01:19, a C3.9 flare at 17:22 and a C1.7 flare at 21:09 UTC. Region 10119 generated a C4.8/1F flare at 02:22, a C3.1 flare at 10:30 and a long duration C2.2 event peaking at 16:00 UTC. September 17: Region 10114 was the source of a long duration C8.6/1F event peaking at 08:20 UTC. The LDE was associated with a halo CME. Although most of the ejected material headed southwestwards, material was seen all around the disk, only faintly over the north pole. The CME will likely cause a geomagnetic disturbance on September 20 with unsettled to active conditions likely, possibly with isolated minor storm intervals. Coronal holes No obvious coronal holes are currently rotating into geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on September 19 and quiet to active or possibly minor storm on September 20. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 Location region numbered no. at Area Classification Comment sunspots midnight 10104 2002.09.07 N09W88 plage beta-gamma too many spots 10105 2002.09.07 21 S09W70 0560 EKO ridiculous area estimate by SEC/NOAA, was just above 0200 at midnight 10106 2002.09.08 N27W81 plage 10107 2002.09.08 3 N11W67 0030 HSX 10108 2002.09.10 S24W58 plage 10109 2002.09.10 S08W88 plage 10110 2002.09.10 1 N19W88 0020 HRX 10111 2002.09.12 N11W77 plage 10112 2002.09.12 N00W74 plage 10114 2002.09.14 1 S11W57 0100 HSX 10115 2002.09.14 21 S03W11 0250 EAI 10116 2002.09.15 6 N15W34 0040 CSO 10117 2002.09.15 1 S09E32 0180 HAX 10118 2002.09.16 N13W14 plage beta-gamma-delta area was near 0400 at 10119 2002.09.16 16 S14E04 0220 DAI midnight. Classification: EKC? Spot count too low 10120 2002.09.16 4 S18E30 0020 BXO 10121 2002.09.16 1 S13E39 0050 HSX 10122 2002.09.16 1 S17E48 0060 HSX 10123 2002.09.17 5 S16E16 0020 BXO 10124 2002.09.18 3 N03W49 0010 CRO 10125 2002.09.18 1 S08E69 0010 AXX Total number of sunspots: 85 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.8 2001.08 162.9 106.4 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.5 114.0 (-0.1) 2001.11 210.6 106.5 115.5 (+1.5) 2001.12 235.1 132.2 114.6 (-0.9) 2002.01 226.6 114.1 113.5 (-1.1) 2002.02 205.0 107.4 114.7 (+1.2) 2002.03 179.5 98.4 (113.2 predicted, -1.5) 2002.04 189.8 120.4 (108.7 predicted, -4.5) 2002.05 178.4 120.8 (104.2 predicted, -4.5) 2002.06 148.7 88.5 (99.7 predicted, -4.5) 2002.07 173.5 99.9 (94.9 predicted, -4.8) 2002.08 183.6 116.4 (90.8 predicted, -4.1) 2002.09 190.7 (1) 130.8 (2) (87.1 predicted, -3.7) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-45% 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]