Last major update issued on March 19, 2011 at 06:40 UTC.
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Annotated geomagnetic activity charts - Carrington rotation
2106 [Jan.-Feb.2011]
- 2107 [Feb.-March
2011] NEW
The geomagnetic field was very quiet on March 18. Solar wind speed ranged between 313-381 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 87.6 (decreasing 21.8 over the last solar rotation). The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.5). Three hour interval K indices: 00100111 (planetary), 11211100 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight UTC the visible solar disk had 7 spotted regions.
Region 11172 decayed and could become spotless today.
Region 11173 decayed losing spots and all traces of penumbra.
Region 11174 developed slowly and was quiet.
New region 11175 emerged in the northeast quadrant on March 17 and was
numbered the next day by NOAA/SWPC.
Spotted regions not numbered by NOAA/SWPC:
[S908] emerged near the northern edge of CH442 on
March 17 and displayed no significant changes on March 18. Location a midnight:
N30E14
[S909] This region emerged in the southwest quadrant on March 17.
Location at midnight: S22W36
[S911] emerged in the southeast quadrant on March 18. Location at midnight:
S22E36
March 16-18: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
Coronal hole history (since late October
2002)
Compare today's report to the situation one solar rotation ago:
28 days ago
27 days
ago 26
days ago
A trans equatorial coronal hole (CH441) was in an Earth facing position on March 18-19. A coronal hole (CH442) in the northern hemisphere will be Earth facing on March 19-20.
The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be mostly quiet on March 19-20. On March 21-24 there's a chance of some unsettled and active intervals due to effects from CH441 and CH442.
| Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
1) Effects from a coronal hole could reach Earth within the
next 5 days. When the high speed stream has arrived the color changes to
green.
2) Effects from a CME are likely to be observed at 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.
(Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
| Active region | Date numbered detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with polarity overlay |
Comment | |||
|---|---|---|---|---|---|---|---|---|---|---|
| SWPC | STAR SDO | SWPC | STAR | Current | Previous | |||||
| 11171 | 2011.03.08 | S19W70 | plage | |||||||
| 11172 | 2011.03.10 2011.03.11 |
4 | N13W25 | 0000 | AXX |
 |
 |
location: N12W23 | ||
| S904 | 2011.03.13 | S24W43 | plage | |||||||
| 11173 | 2011.03.15 2011.03.16 |
9 | 12 | S29E14 | 0030 | CRO | BXO |
 |
 |
|
| S906 | 2011.03.16 | N21W30 | plage | |||||||
| 11174 | 2011.03.16 2011.03.17 |
3 | N22W50 | 0000 | BXO |
 |
 |
|||
| S908 | 2011.03.17 | 2 | N30E14 | 0000 | AXX |
 |
 |
|||
| S909 | 2011.03.17 | 2 | S22W36 | 0010 | BXO |
 |
 |
|||
| 11175 | 2011.03.17 2011.03.18 |
6 | 12 | N13W09 | 0020 | CRO | CAI |
 |
 |
formerly region S910 area: 0070 |
| S911 | 2011.03.18 | 2 | S22E36 | 0000 | BXO |
 |
||||
| Total spot count: | 15 | 37 | ||||||||
| Sunspot number: | 35 | 107 | ||||||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 2008.07 | 65.7 (SF minimum) | 0.5 | 2.8 (-0.4) | |
| 2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
3.25 |
| 2009.12 | 76.7 | 10.8 | 8.3 (+0.7) | 1.41 / 1.92 |
| 2010.01 | 81.1 | 13.2 | 9.3 (+1.0) | 2.93 / 3.07 |
| 2010.02 | 84.7 | 18.8 | 10.6 (+1.3) | 4.15 / 4.61 |
| 2010.03 | 83.4 | 15.4 | 12.3 (+1.7) | 4.58 / 4.65 |
| 2010.04 | 75.9 | 8.0 | 14.0 (+1.7) | 10.22 / 10.24 |
| 2010.05 | 73.8 | 8.7 | 15.5 (+1.5) | 9.18 / 8.15 |
| 2010.06 | 72.5 | 13.6 | 16.4 (+0.9) | 8.17 / 6.85 |
| 2010.07 | 79.8 | 16.1 | 16.8 (+0.4) | 6.31 / 5.15 |
| 2010.08 | 79.2 | 19.6 | 17.4 (+0.6) | 8.49 / 7.77 |
| 2010.09 | 81.1 | 25.2 | (19.1 predicted, +1.7) | 5.33 / 5.45 |
| 2010.10 | 81.6 | 23.5 | (21.7 predicted, +2.6) | 6.07 / 6.27 |
| 2010.11 | 82.5 | 21.6 | (24.5 predicted, +2.8) | 4.80 / 5.50 |
| 2010.12 | 84.2 | 14.5 | (26.9 predicted, +2.4) | 3.41 / 4.35 |
| 2011.01 | 83.6 | 19.1 | (29.0 predicted, +2.1) | 4.32 |
| 2011.02 | 94.6 | 29.4 | (31.1 predicted, +2.1) | 5.41 |
| 2011.03 | 120.1 (1) | 48.9 (2A) / 84.2 (2B) | (33.0 predicted, +1.9) | (10.44) |
1) Running average based on the daily 20:00 UTC observed solar flux value at
2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder
(NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The
official SIDC international sunspot number is typically 30-50% lower. 2B) Month
average to date.
3) Running average based on the preliminary daily SWPC ap indices.
Values in red are based on the official NGDC
ap indices.
This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.
