Solar Terrestrial Activity Report [Image] Last update February 21, 2001 at 05:10 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 to unsettled on February 20. Solar wind speed ranged between 282 and 358 km/sec. A weak solar wind shock was observed at 01 UT. Solar wind speed increased abruptly from 280 to 310 km/sec. Solar flare activity was low. Solar flux was 145.5, the planetary A index was 8 (3-hour K indices: 1123 3222, Boulder K indices: 2124 3212). Region 9349 was quiet and decayed slowly, no spots were observed after noon. Regions 9350, 9352 and 9353 were quiet and stable, region 9352 appears to be spotless early on Feb.21. Region 9354 was mostly unchanged and could produced C flares and perhaps a minor M class flare. Regions 9357 and 9358 were quiet and stable. New region 9359 rotated into view at the northeast limb, the region may be capable of C class flare production. Oddly a region which rotated into view at the southeast limb was not numbered by SEC/NOAA. Flares and CMEs A total of 4 C class event was observed on February 20. Region 9354 produced a C2.2 flare at 14:51 and a C2.1 flare at 15:41 UT. A C3.1 flare at 01:22 UT may have had its source just behind the east limb. The background x-ray flux is at the class B3 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 21-22. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is fair to 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 9347 2001.02.09 N05W80 plage 9349 2001.02.10 1 N30W69 0020 HRX 9350 2001.02.11 1 N19W50 0060 HSX 9352 2001.02.15 1 S21E02 0010 AXX 9353 2001.02.16 4 S22W36 0040 DAO 9354 2001.02.16 18 S08W20 0150 DAO beta-gamma 9355 2001.02.18 N20E08 plage 9356 2001.02.18 S13W36 plage 9357 2001.02.18 2 S26E06 0020 CSO 9358 2001.02.18 9 S08E20 0050 DAO 9359 2001.02.20 3 N10E74 0080 CSO Total number of sunspots: 39 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) 2001.02 150.1 (1) 100.0 (2) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value. The official value 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]