Solar Terrestrial Activity Report [Image] Last update February 25, 2002 at 05:00 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update February 2, 2002)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2002)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 2002)] [Historical solar and geomagnetic data charts 1954-2001 (last update January 12, 2002)] Recent development The geomagnetic field was quiet on February 24. Solar wind speed ranged between 313 and 368 km/sec. Solar flare activity was low. Solar flux was 192.8, the planetary A index was 4 (3-hour K indices: 2111 2111, Boulder K indices: 1112 3222). Region 9830 decayed significantly, particularly during the latter half of the day, losing many spots and quite a bit of penumbral area. M class flares are still possible. Region 9837 was mostly unchanged during the first half of the day, then decayed and lost most of the spots outside of the main penumbra. Region 9839 developed further and could soon become capable of minor M class flare generation. Region 9840 decayed into spotless plage by noon. Region 9841 decayed slowly and was mostly quiet. Region 9842 developed slowly and quietly. Region 9843 decayed and could soon become spotless. Region 9844 developed further and could produce minor M class flares. Region 9845 was quiet and stable. New region 9846 emerged in the southwest quadrant. New region 9847 emerged in the southeast quadrant. Flares and CMEs A total of 9 C class events were recorded on February 24. Region 9830 produced a C1.3 flare at 04:38, a C2.4 flare at 15:40 and a C9.0 flare at 20:38 UTC. Region 9841 generated a C4.4 flare at 14:47 UTC with an associated weak type II radio sweep. Region 9844 was the source of a C5.2 flare at 20:52 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 unsettled on February 25-27. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to good. 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 9829 2002.02.14 S06W53 plage 9830 2002.02.14 20 S17W64 0650 FKC beta-gamma-delta area way too large 9832 2002.02.18 S15W55 plage 9833 2002.02.19 N11W81 plage 9834 2002.02.19 N03W13 plage 9836 2002.02.20 S02W78 plage 9837 2002.02.20 8 N10E18 0080 DAO 9838 2002.02.21 N05W58 plage 9839 2002.02.21 14 S17W35 0080 DAI 9840 2002.02.21 1 S11E33 0020 HSX now spotless 9841 2002.02.22 7 S20W47 0070 DAO 9842 2002.02.22 5 S19W23 0020 CSO 9843 2002.02.22 2 S25E33 0020 CRO 9844 2002.02.23 10 N22E18 0100 DSO beta-gamma 9845 2002.02.23 2 N15E58 0060 HAX 9846 2002.02.24 5 S04W37 0020 DAO 9847 2002.02.24 7 S15E50 0050 CSO 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 2000.12 173.6 104.4 112.0 (-0.7) 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 (113.5 predicted, +1.8) 2001.09 233.2 150.7 (113.3 predicted, -0.2) 2001.10 207.6 125.6 (111.0 predicted, -2.3) 2001.11 210.6 106.5 (109.6 predicted, -1.4) 2001.12 235.1 131.8 (106.2 predicted, -3.4) 2002.01 226.6 113.9 (102.6 predicted, -3.6) 2002.02 205.0 (1) 164.5 (2) (101.2 predicted, -1.4) 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 25-40% 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 noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News]