Solar Terrestrial Activity Report [Image] Last update April 1, 2002 at 02:25 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update March 4, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update March 4, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 4, 2002)] [Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 2002)] Recent development The geomagnetic field was quiet to active on March 31. Solar wind speed ranged between 610 and 771 km/sec under the influence of a high speed solar coronal stream. Solar flare activity was moderate. Solar flux was 204.4, the planetary A index was 14 (3-hour K indices: 2333 3343, Boulder K indices: 2343 3332). Region 9876 decayed slowly and is rotating over the southwest limb. Region 9878 decayed slowly and quietly and will soon be rotating over the northwest limb. Region 9884 developed early in the day, then began to decay. The region was quiet. Region 9885 decayed in the intermediate spots section and is currently not very complex. An M class flare is possible. Region 9886 developed slowly and could produce a minor M class flare. Region 9887 developed at a moderate pace and is capable of producing an M class flare. Region 9888 developed slowly and could generate a minor M class flare. New region 9889 to the south of region 9888 was finally numbered by SEC/NOAA, the region appears to be decaying. [On a general note the Boulder SSN of 133 for March 31 is exceptionally low. Boulder often has an SSN similar to the Learmonth (Australia) SSN but with the latter at a more reasonable 240 (with the same number of regions) early on April 1, there is a huge difference in observed spots - 53 compared to 160.] Flares and CMEs A total of 4 C and 1 M class events were recorded on March 31. Region 9885 produced a C2.9 flare at 10:10 and an M1.0/1F long duration event peaking at 10:55 UTC. Region 9886 generated a C5.2 flare at 14:53 UTC. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be quiet to active on April 1 due to a coronal stream and 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 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 Location region numbered no. at Area Classification Comment sunspots midnight 9876 2002.03.20 1 S14W82 0000 AXX 9878 2002.03.20 2 N08W68 0020 BXO 9882 2002.03.22 N16W51 plage 9883 2002.03.23 N07W36 plage 9884 2002.03.27 5 S19W11 0100 DAO spot count too low beta-gamma 9885 2002.03.27 19 N10E14 0600 EHI area and spot count too low beta-gamma 9886 2002.03.29 8 N11E30 0100 DSO area and spot count too low beta-gamma 9887 2002.03.29 11 N01E37 0240 EAI area and spot count too low 9888 2002.03.29 5 S13E46 0190 DSO area and spot count too low 9889 2002.03.31 2 S20E48 0020 CSO Total number of sunspots: 53 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 2001.01 166.6 95.6 108.7 (-3.3) 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 (113.7 predicted, +0.1) 2001.10 207.6 125.6 (111.7 predicted, -2.0) 2001.11 210.6 106.5 (110.2 predicted, -1.5) 2001.12 235.1 131.8 (106.9 predicted, -3.3) 2002.01 226.6 113.9 (103.3 predicted, -3.6) 2002.02 205.0 108.0 (101.9 predicted, -1.4) 2002.03 179.5 (1) 152.8 (2) (97.6 predicted, -4.3) 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]