Solar Terrestrial Activity Report [Image] Last update March 19, 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 unsettled on March 18. Solar wind speed ranged between 281 and 343 km/sec. Solar flare activity was low. Solar flux was 139.8, the planetary A index was 7 (3-hour K indices: 3322 1222, Boulder K indices: 3321 1112). Region 9373 decayed in the leader spot section. The section with the trailer spots has become much more complex and could lead to the production of minor M class flares. Region 9380 reemerged with a single spot but had decayed into spotless plage again by early evening. Region 9384 was mostly quiet and stable. Region 9385 decayed and was spotless by late morning. New region 9386 emerged in the northwest quadrant. A couple of active regions are approaching the east limb, the one just behind the northeast limb appears to be interesting. Flares and CMEs A total of 6 C class events were recorded on March 18. Region 9373 produced a C1.9 flare at 05:24, a C3.4 flare at 07:48, a C3.1 flare at 08:50 (a moderate type II sweep was associated with this flare, observation of any CME was not possible as LASCO images were unavailable) and a C1.8 flare at 11:09 UT. Region 9384 generated a C1.9 flare at 17:33 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 B5 level. Coronal holes A small, well placed coronal hole in the northern hemisphere will rotate into a geoeffective position on March 19-20. Geomagnetic effects beyond a few unsettled to active intervals on March 22-23 are unlikely. Forecast The geomagnetic field is expected to be quiet to unsettled on March 19-20 with a possibility of a few active intervals due to CME effects. 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 Location region numbered no. at Area Classification Comment sunspots midnight 9373 2001.03.09 27 S07W43 0220 FAO beta-gamma-delta? 9374 2001.03.10 S17W49 plage 9376 2001.03.11 S13W17 plage 9379 2001.03.12 N31W38 plage 9380 2001.03.12 1 S08W10 0000 AXX plage 9381 2001.03.13 S17W30 plage 9384 2001.03.14 10 N11W49 0060 DRO 9385 2001.03.17 1 S11E27 0000 AXX 9386 2001.03.18 2 N03W11 0000 AXX Total number of sunspots: 41 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) 2001.03 148.7 (1) 68.5 (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]