Solar Terrestrial Activity Report [Image] Last update March 24, 2002 at 04:40 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 unsettled on March 23. Solar wind speed ranged between 377 and 490 km/sec. A solar wind shock was observed at SOHO at 10:46 UTC. Solar wind speed increased suddenly from 380 to 470 km/sec. The source of this shock is likely a faint full halo CME observed on March 20. The interplanetary magnetic field has swung gradually stronger southwards since the shock and the geomagnetic field is now at active levels. A few magnetometers have recorded minor storm levels. Solar flare activity was low. Solar flux was 170.4, the planetary A index was 9 (3-hour K indices: 1002 3333, Boulder K indices: 1002 4333). Region 9871 decayed slowly and quietly. Region 9873 rotated over the southwest limb. Region 9875 decayed slowly and quietly. Region 9876 developed further and was fairly active producing quite a few low level C class flares. Region 9878 was mostly unchanged and quiet. The region could produce minor M class flares. Region 9879 developed slowly and is rotating over the northwest limb. Region 9880 developed slowly and quietly. Region 9881 developed slowly as well and was quiet. Region 9882 did not change significantly and was quiet. New region 9883 rotated into view at the northeast limb. Flares and CMEs A total of 12 C class events were recorded on March 23. Region 9876 produced a C1.1 flare at 01:49, a C3.2 flare at 04:44, a C3.5 flare at 14:36 and a C2.6 flare at 19:18 UTC. Region 9878 generated a C2.1 flare at 03:30 UTC. March 22: A long duration M1.6 event peaked at 11:14 UTC. The source of this activity was at the southwest limb near regions 9866, 9870 and 9873. A fast and wide full halo CME was observed in LASCO C3 images in association with the LDE. Although the main part of the CME will not impact the Earth, some geomagnetic effects are likely on March 25. The background x-ray flux is at the class B6 level. Coronal holes A small coronal hole in the northern hemisphere is in a geoeffective position on March 24. A recurrent trans equatorial coronal hole will rotate into a geoeffective position on March 29-31. Forecast The geomagnetic field is expected to be unsettled to active on March 24 and quiet to active on March 25. A weak coronal stream related disturbance could start on March 27. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9871 2002.03.13 5 S18W60 0170 DSO area too large 9873 2002.03.17 1 S17W93 0050 HAX 9874 2002.03.19 N18W30 plage 9875 2002.03.19 12 S20E08 0110 DAO 9876 2002.03.20 18 S16E30 0160 EAO beta-gamma 9877 2002.03.20 N15W70 plage 9878 2002.03.20 15 N10E43 0150 FAO beta-gamma 9879 2002.03.21 9 N14W76 0210 DAO beta-gamma 9880 2002.03.21 5 N06E07 0020 CRO 9881 2002.03.22 4 S04W20 0020 BXO 9882 2002.03.22 6 N14E54 0130 DAO 9883 2002.03.23 1 N06E67 0030 HSX Total number of sunspots: 76 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) 2002.03 179.7 (1) 111.1 (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]