Solar Terrestrial Activity Report [Image] Last update March 18, 2001 at 04:15 UT. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update March 1, 2001) - Cycle 23 sunspot maximum was in April 2000] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update March 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update March 1, 2001)] [Historical solar and geomagnetic data charts 1954-2000 (last update January 18, 2001)] Recent development The geomagnetic field was quiet to slightly unsettled on March 17. Solar wind speed ranged between 285 and 342 km/sec. Solar flare activity was low. Solar flux was 134.2, the planetary A index was 4 (3-hour K indices: 0000 2321, Boulder K indices: 0001 2321). Region 9373 decayed slowly, further C class flaring is possible. Region 9376 was quiet and stable, the region is spotless early on March 18. Region 9383 was quiet and stable and has rotated off the visible disk. Region 9384 decayed slowly and was mostly quiet. New region 9385 emerged in the southeast quadrant, the region has already decayed considerably and has only a single small spot left early on March 18. Flares and CMEs A total of 2 C class events were recorded on March 17. Region 9373 produced a C3.9 flare at 17:20 UT. March 15: A filament eruption occurred near region 9384 and was in progress by 21:13 UT according to LASCO EIT images. The eruption was the likely source of a low speed halo CME observed early on March 16. The background x-ray flux is at the class B3 level. Coronal holes A small, well placed coronal hole in the southern hemisphere was in a geoeffective position on March 14. Only minor, if any, effects on the geomagnetic field are likely on March 17-18. The huge southern polar coronal hole is slowly becoming more well defined. A northerly extension may have been in a geoeffective position on March 16-17 and could cause some geomagnetic activity on March 19 and 20. Forecast The geomagnetic field is expected to be quiet to unsettled on March 18. Sometime between late on March 18 and late on March 19 a CME based disturbance is likely to arrive and could 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 9373 2001.03.09 22 S07W34 0230 FAO 9374 2001.03.10 S17W36 plage 9376 2001.03.11 4 S13W04 0020 CRO 9377 2001.03.11 S18W78 plage 9379 2001.03.12 N31W25 plage 9380 2001.03.12 S09E01 plage 9381 2001.03.13 S17W17 plage 9383 2001.03.14 1 S10W82 0050 HSX 9384 2001.03.14 9 N12W35 0100 DAO 9385 2001.03.17 4 S13E42 0030 DRO Total number of sunspots: 40 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 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) 2000.04 184.2 125.5 120.8 (+0.9) cycle 23 sunspot max. 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) 2000.08 163.0 130.5 118.6 (-1.2) 2000.09 182.1 109.7 (115.4 predicted, -3.2) 2000.10 167.4 100.1 (113.0 predicted, -2.4) 2000.11 178.8 106.5 (111.0 predicted, -2.0) 2000.12 173.6 104.5 (108.5 predicted, -2.5) 2001.01 166.6 95.7 (104.7 predicted, -3.8) 2001.02 146.6 80.1 (100.3 predicted, -4.4) 2001.03 149.2 (1) 65.6 (2) (96.8 predicted, -3.5) 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. ------------------------------------------------------------------------ Do you know about the survey which will be held this Summer among the listeners of WWV and WWVH? There is information about this survey at 16 minutes past the hour on WWV and at 47 minutes past the hour on WWVH. If you want to participate send an email with your name and address. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]