Solar Terrestrial Activity Report [Image] Last update February 26, 2001 at 03:00 UT. [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, 2001) - Did cycle 23 peak in April 2000?] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update February 2, 2001)] [Historical solar and geomagnetic data charts 1954-2000 (last update January 18, 2001)] Recent development The geomagnetic field was quiet on February 25. Solar wind speed ranged between 290 and 329 km/sec. Solar flare activity was very low. Solar flux was 134.9, the planetary A index was 3 (3-hour K indices: 0011 1210, Boulder K indices: 1112 1100). Region 9354 was quiet and stable and is rotating over the west limb. Region 9357 was nearly spotless early in the day, then began to develop at a moderate pace. Region 9358 was spotless until approximately noon when a single spot appeared. Region 9359 was decaying early in the day, then developed several new spots and became more complex. The region has a fair chance of generating a minor M class flare. Region 9360 was quiet and stable. Region 9361 was spotless all day, SEC/NOAA somehow managed to observe one spot. New region 9362 emerged early in the day but was spotless within hours. Flares and CMEs No flaring of interest occurred on February 25. February 23: A long duration C2.2 event peaked at 23:19 UT, its source was in the southeast quadrant, just east of region 9360. A coronal mass ejection was produced and could be observed in LASCO images before midnight. The CME appears to have been a faint full halo CME. The background x-ray flux is at the class B3 level. Coronal holes A small, well placed coronal hole in the northern hemisphere was in a geoeffective position on February 23. A coronal hole in the southern hemisphere may have been located too far to the south to have been geoeffective when it rotated across the central meridian on Feb.23-24. Forecast The geomagnetic field is expected to be initially quiet on February 26, quiet to unsettled with a chance of active intervals is possible later in the day due to the likely arrival of a coronal stream. Sometime between late on February 26 and late on February 27 a weak CME will likely impact the magnetosphere and cause unsettled to active conditions. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair. 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 region numbered sunspots at AreaClassification Comment midnight 9352 2001.02.15 S21W61 9354 2001.02.16 5 S09W83 0200 DAO 9355 2001.02.18 N20W57 plage 9357 2001.02.18 8 S25W57 0060 CSO 9358 2001.02.18 1 S10W43 0010 AXX 9359 2001.02.20 22 N13E10 0170 DAI beta-gamma 9360 2001.02.21 3 S11E04 0020 CSO 9361 2001.02.22 1 S15W36 0010 AXX actually spotless! 9362 2001.02.25 1 S07E12 0010 AXX now spotless Total number of sunspots: 41 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 1999.11 191.5 133.2 111.0 (+3.2) 1999.12 169.8 84.6 111.1 (+0.1) 2000.01 158.1 90.1 112.9 (+1.8) 2000.02 174.1 112.9 116.8 (+3.9) 2000.03 208.2 138.5 119.9 (+3.1) 120.8 (+0.9) 2000.04 184.2 125.5 cycle 23 peak candidate 2000.05 184.9 121.6 119.0 (-1.8) 2000.06 179.8 124.9 118.7 (-0.3) 2000.07 202.3 170.1 119.8 (+1.1) 2000.08 163.0 130.5 (119.5 predicted, -0.3) 2000.09 182.1 109.7 (117.9 predicted, -1.6) 2000.10 167.4 100.1 (116.3 predicted, -1.6) 2000.11 178.8 106.5 (114.4 predicted, -1.9) 2000.12 173.6 104.5 (111.8 predicted, -2.6) 2001.01 166.6 95.7 (108.2 predicted, -3.6) 2001.02 148.3 (1) 121.4 (2) 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] [StudyWeb]