Solar Terrestrial Activity Report [Image] Last update February 19, 2001 at 03:55 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 18. Solar wind speed ranged between 273 and 363 km/sec. The predicted disturbance failed to arrive, however, solar wind density has been fairly high since about 16 UT on Feb.18 and has increased further early on Feb.19. There is still a possibility the disturbance could arrive, although later than first expected. Solar flare activity was low. Solar flux was 132.0, the planetary A index was 4 (3-hour K indices: 1000 1222, Boulder K indices: 1000 1211). Region 9349 was quiet and stable, as were regions 9350, 9352 and 9353. Region 9351 reemerged with a single spot and will rotate over the west limb today. Region 9354 was quiet and developed slowly. New region 9355 in the northeast quadrant was finally numbered. New region 9356 emerged in the southwest quadrant near the central meridian. New regions 9357 and 9358 emerged in the southeast quadrant. Flares and CMEs Only 1 C class event was observed on February 18, it was a long duration C1.7 event peaking at 19:29 UT. Its source is unknown. February 15: A fairly extensive filament eruption started shortly after 12:48 UT in LASCO EIT images, it started near region 9350 and spread northwestwards and southeastwards towards the equator and just into the southern hemisphere. A full halo CME was observed in LASCO C3 images with a front first appearing above the northeast limb and the north pole. 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 with possible active intervals on February 19. 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 at region numbered sunspots midnight Area Classification Comment 9347 2001.02.09 N05W54 plage 9349 2001.02.10 1 N28W44 0020 HRX 9350 2001.02.11 1 N18W23 0070 HSX 9351 2001.02.15 2 S20W81 0010 CSO 9352 2001.02.15 6 S23E25 0020 CSO 9353 2001.02.16 6 S22W10 0030 CSO 9354 2001.02.16 14 S09E07 0110 DAO 9355 2001.02.18 4 N20E35 0020 CRO 9356 2001.02.18 4 S13W10 0010 BXO 9357 2001.02.18 3 S26E35 0040 HSX 9358 2001.02.18 2 S08E46 0010 BXO Total number of sunspots: 43 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) 2001.02 151.1 (1) 90.5 (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]