Solar Terrestrial Activity Report [Image] Last update April 2, 2002 at 03:35 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update April 2, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update April 2, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update April, 2002)] [Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 2002)] Recent development The geomagnetic field was quiet to active on April 1. Solar wind speed ranged between 609 and 776 km/sec under the influence of a high speed solar coronal stream. Solar flare activity was low. Solar flux was 207.0, the planetary A index was 16 (3-hour K indices: 3443 3332, Boulder K indices: 2432 3331). Region 9876 rotated quietly over the southwest limb. Region 9878 decayed into spotless plage and is rotating over the northwest limb. Region 9884 decayed slowly and quietly. Region 9885 was mostly unchanged and remains capable of producing an M class flare. Mixed magnetic polarities are observed in the trailing spots section. Region 9886 did not change significantly and could produce a minor M class flare. Region 9887 developed quickly in the trailing spots section and could soon become the largest visible region. A major flare is possible. Region 9888 developed slowly and quietly, a minor M class flare is possible. Region 9889 was quiet and stable. SEC/NOAA failed to number two new small regions, one which emerged near the center of the solar disk and another which emerged to the west of region 9884. Both regions could become spotless today. Flares and CMEs A total of 5 C class events were recorded on April 1. Region 9885 produced a C1.9 flare at 14:46 UTC. Region 9886 generated a C3.0 flare at 15:39 UTC. A full halo CME was observed in LASCO C3 images beginning at approximately 14:00 UTC on April 1. The absence of LASCO EIT images makes it difficult to tell if the source of this CME was on the visible disk (as there were no particularly interesting x-ray events just prior to the observation of the CME the possibility of a front side event is fairly small) or backsided. The background x-ray flux is at the class B8 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to unsettled on April 2-3. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to 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 9876 2002.03.19 3 S18W92 0010 HRX 9878 2002.03.20 2 N08W82 0020 HRX 9882 2002.03.22 N16W64 plage 9883 2002.03.23 N07W49 plage 9884 2002.03.27 9 S19W25 0120 DSO 9885 2002.03.27 33 N11E01 0710 EKI beta-gamma 9886 2002.03.29 21 N11E16 0180 DAO beta-gamma 9887 2002.03.29 25 N01E24 0490 DKI beta-gamma 9888 2002.03.29 14 S13E32 0330 DAO 9889 2002.03.31 2 S20E30 0020 HSX Total number of sunspots: 109 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 2001.02 146.6 80.6 104.1 (-4.6) 2001.03 177.7 113.5 104.8 (+0.7) 2001.04 177.7 107.7 107.6 (+2.8) 2001.05 147.1 96.6 108.7 (+1.1) 2001.06 173.0 134.0 109.8 (+1.1) 2001.07 131.3 82.2 111.7 (+1.9) 2001.08 162.9 106.8 113.6 (+1.8) 2001.09 233.2 150.7 114.1 (+0.5) 2001.10 207.6 125.6 (112.7 predicted, -1.4) 2001.11 210.6 106.5 (111.5 predicted, -1.2) 2001.12 235.1 131.8 (108.2 predicted, -3.3) 2002.01 226.6 113.9 (104.8 predicted, -3.4) 2002.02 205.0 108.0 (103.4 predicted, -1.4) 2002.03 179.5 98.1 (99.1 predicted, -4.3) 2002.04 207.0 (1) 6.3 (2) (93.2 predicted, -5.9) 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]