Solar Terrestrial Activity Report [Image] Last update February 5, 2001 at 05:15 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) - Cycle 23 peaked 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 4. Solar wind speed ranged between 308 and 347 km/sec. Solar flare activity was low. Solar flux was 148.1, the planetary A index was 2 (3-hour K indices: 0000 1110, Boulder K indices: 0000 0210). Region 9325 was quiet and stable, the region is spotless early on Feb.5. Regions 9327 was quiet and stable. Region 9330 decayed slowly and could produce further C class flares. Region 9333 was quiet and stable. Region 9334 was mostly unchanged and could produce C and minor M class flares. Region 9335 was quiet and stable and may be capable of isolated minor M class flare production. Region 9336 was quiet and stable, no spots are visible early on Feb.5. Region 9337 was quiet and stable. New region 9338 rotated into view at the southeast limb. New region 9339 rotated partly into view at the southeast limb and could produce minor M class flares. Flares and CMEs A total of 9 C class events were recorded on February 4. Region 9330 produced a C1.7 flare at 00:22 and a C2.5 flare at 08:41 UT. Region 9334 generated a C1.7 flare at 02:53, a C1.0 flare at 12:45 and a C1.3 flare at 23:13 UT. The background x-ray flux is at the class B5 level. Coronal holes An isolated coronal hole in the northern hemisphere was in a geoeffective position on February 3-4. Forecast The geomagnetic field is expected to be mostly quiet on February 5. A coronal stream could influence the field from February 6 and is likely to cause unsettled to active conditions. 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 no. Location at region numbered sunspots midnight Area Classification Comment 9325 2001.01.25 1 N11W74 0000 AXX 9327 2001.01.27 5 N17W62 0050 CAO 9329 2001.01.29 S09W27 plage 9330 2001.01.30 17 N25E04 0130 EAI 9331 2001.01.30 N13W39 plage 9332 2001.01.30 N09W45 plage 9333 2001.02.01 5 N25W50 0030 CSO 9334 2001.02.01 18 N11E41 0220 EAI 9335 2001.02.03 9 N08E52 0130 DAO 9336 2001.02.03 3 S10W17 0010 BXO 9337 2001.02.03 1 S27E60 0020 HSX 9338 2001.02.04 2 S17E59 0030 HRX 9339 2001.02.04 3 S12E74 0070 HSX beta-gamma Total number of sunspots: 64 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 (119.7 predicted, -0.1) 2000.09 182.1 109.7 (118.4 predicted, -1.3) 2000.10 167.4 100.1 (116.7 predicted, -1.7) 2000.11 178.8 106.5 (114.8 predicted, -1.9) 2000.12 173.6 104.5 (112.2 predicted, -2.6) 2001.01 166.6 95.7 (108.7 predicted, -3.5) 2001.01 159.7 (1) 20.1 (2) 1) Running average based on the daily 20:00 UTC 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]