Solar Terrestrial Activity Report [Image] Last update February 17, 2001 at 05:25 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 16. Solar wind speed ranged between 450 and 513 km/sec. Solar flare activity was low. Solar flux was 129.6 (lowest solar flux since May 7, 2000), the planetary A index was 3 (3-hour K indices: 0001 1122, Boulder K indices: 0101 1212). Regions 9338 and 9339 rotated over the west limb, region 9338 was only barely visible for the first couple of hours of the day and SEC/NOAA would have done better not to include this region in the spot count for the day (the spot count was inflated because of this inclusion and because 2 spotless regions, see below, were included as well). Region 9342 was spotless all day in all available images (SEC/NOAA apparently observed 2 spots). Region 9347 decayed quickly and was spotless by noon. Region 9348 was quiet and stable. Region 9349 is decaying slowly and could become spotless within 2-3 days. Region 9350 was quiet and stable. Region 9351 was spotless all day, again SEC/NOAA mistakenly attributed 2 spots to the region. Region 9352 was quiet and stable. New region 9353 emerged in the southeast quadrant. New region 9354 emerged in the southeast quadrant, the region is already spotless. Flares and CMEs Only 1 C class event was observed on February 16, it was a long duration C1.1 event which had its source just behind the northwest limb. 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 CME will impact Earth's magnetosphere on February 18. The background x-ray flux is at the class B2 level. Coronal holes A small but well placed coronal hole in the southern hemisphere was in a geoeffective position on February 14-15. Forecast The geomagnetic field is expected to be quiet most of February 17. A coronal stream could arrive late on February 17 and cause a few unsettled to active intervals. Another disturbance will likely start on February 18 when a CME arrives at Earth, unsettled to minor storm conditions are possible. 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 region numbered sunspots at AreaClassification Comment midnight 9338 2001.02.04 1 S22W94 0060 HSX 9339 2001.02.04 1 S11W92 0060 HSX 9342 2001.02.06 2 S23W65 0000 BXO actually spotless! 9345 2001.02.08 S20W84 plage 9347 2001.02.09 3 N04W29 0010 CSO now spotless 9348 2001.02.10 7 N15W73 0110 DAO 9349 2001.02.10 1 N28W18 0030 HSX 9350 2001.02.11 1 N18E04 0060 HSX 9351 2001.02.15 2 S23W53 0030 CSO actually spotless! 9352 2001.02.15 2 S22E51 0010 BXO 9353 2001.02.16 2 S23E17 0010 HSX 9354 2001.02.16 1 S09E34 0000 AXX Total number of sunspots: 23 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) 2001.02 153.6 (1) 82.0 (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]