Solar Terrestrial Activity Report [Image] Last update March 23, 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)] [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 active on March 22. Solar wind speed ranged between 298 and 399 km/sec. A solar wind shock was observed at ACE at 12:47 UT. Solar wind speed increased suddenly from 300 to 350 km/sec and the interplanetary magnetic field strengthened significantly. The source of this disturbance is likely the halo CME observed on March 19. Solar flare activity was moderate. Solar flux was 183.0, the planetary A index was 10 (3-hour K indices: 1011 3423, Boulder K indices: 1121 3533). Region 9373 rotated off the visible disk. Region 9376 reemerged and has developed slowly, the region will rotate over the west limb on March 24. Region 9387 was mostly quiet and stable. Region 9388 was quiet, the region is spotless early on March 23. Region 9389 was quiet and stable but could produce occasional minor M class flares. Region 9390 was mostly unchanged and has minor M class flare potential. Region 9392 was quiet and mostly stable. Otherwise region 9385 has reemerged early on March 23 with a single spot. Three new spotted regions are visible at the east limb, a small region at the southeast limb, a large region at the northeast limb (this region probably has major flare potential and is the region "responsible" for the large increase in solar flux), and a small region due south of the large region. Flares and CMEs A total of 3 C and 3 M class events were recorded on March 22. Region 9390 produced an M1.0 flare at 13:19 UT. This was the only optically associated flare. LASCO EIT images indicate that the new large region at the northeast limb was the source of most of the remaining flares, an M1.0 flare at 05:15, an M1.6 flare at 08:21, a long duration C7.8 flare peaking at 16:27 and a C5.7 flare at 23:00 UT. The background x-ray flux is at the class C1 level. Coronal holes A coronal hole in the northern hemisphere was in a geoeffective position on March 22 and could cause unsettled to active conditions on March 25. Fingers of a fairly large southern hemisphere coronal hole will rotate into possibly geoeffective positions on March 22 and 24 and could cause unsettled to active conditions on March 25 and 27. Forecast The geomagnetic field is expected to be quiet to active on March 23 and quiet to unsettled on March 24. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is very 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 at region numbered sunspots midnight Area Classification Comment 9373 2001.03.09 4 S05W92 0060 HSX 9376 2001.03.11 2 S14W73 0030 CAO 9380 2001.03.12 S08W64 plage 9381 2001.03.13 S17W82 plage 9385 2001.03.17 S11W25 plage 9386 2001.03.18 N04W66 plage 9387 2001.03.19 18 N08E21 0140 CAO 9388 2001.03.20 4 N14W75 0030 CRO 9389 2001.03.20 8 S13E54 0180 EAO beta-gamma 9390 2001.03.20 16 N15E46 0300 FAO beta-gamma 9391 2001.03.21 S04W28 plage 9392 2001.03.21 7 N19W29 0030 DAO Total number of sunspots: 59 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) 2001.03 150.9 (1) 83.0 (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]