Last major update issued on May 10, 2011 at 04:35 UTC.
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Annotated geomagnetic activity charts - Carrington rotation
2107 [Feb.-March
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2011]
The geomagnetic field was quiet on May 9. Solar wind speed ranged between 272 and 350 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 103.7 (decreasing 6.7 over the last solar rotation). The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 11001111 (planetary), 11011311 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight UTC the visible solar disk had 9 spotted regions.
Region 11203 was quiet and stable.
Region 11204 was quiet and stable.
Region 11205 was quiet and stable.
Region 11207 was quiet and stable.
Region 11208 developed slowly and was quiet.
Region 11209 was quiet and stable.
New region 11210 emerged in the northeast quadrant on May 5 and was
numbered by NOAA/SWPC 4 days later. The region developed fairly quickly early in
the day. Further C flares are possible. Flares:
C1.4 at 05:16 and C1.5 at 17:41 UTC
New region 11211 was first observed with spots on May 4, became spotless,
then reemerged on May 8 and got an SWPC number on May 9.
Spotted regions not numbered by NOAA/SWPC:
[S999] rotated into view at the southeast limb on May 9. Location at midnight:
S14E78
A C5.4 flare was recorded at 20:59 UTC. Its source was a region currently at or just behind the northeast limb. The flare was associated with a fairly fast and large CME off the northeast limb.
May 7-9: 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 coronal hole (CH448) in the southern hemisphere will likely rotate into an Earth facing position on May 12.
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 fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be mostly quiet on May 10-13.
| 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 | |||||
| 11203 | 2011.04.28 | 1 | 1 | N18W68 | 0120 | HSX | HSX |
 |
 |
|
| 11204 | 2011.04.30 2011.05.02 |
3 | 6 | N17W57 | 0100 | CAO | CSO |
 |
 |
|
| 11205 | 2011.04.30 2011.05.02 |
1 | N14W47 | 0000 | AXX |
 |
 |
location: N23W33 | ||
| S990 | 2011.05.03 | N29W31 | plage |
|||||||
| 11207 | 2011.05.03 2011.05.05 |
7 | N24W16 | 0000 | BXO |
 |
 |
location: N21W20 |
||
| 11211 | 2011.05.04 2011.05.09 |
2 | 6 | S12W23 | 0010 | BXO | BXO |
 |
 |
formerly region S992 |
| 11210 | 2011.05.05 2011.05.09 |
13 | 26 | N20E08 | 0030 | DSI | CSI |
 |
 |
formerly region S993 area: 0090 |
| S994 | 2011.05.06 | S23W45 | plage | |||||||
| 11208 | 2011.05.07 2011.05.08 |
9 | 9 | N12E36 | 0100 | DSO | DSO |
 |
 |
|
| 11209 | 2011.05.07 2011.05.08 |
5 | 6 | N35W05 | 0010 | BXO | BXO |
 |
 |
|
| S997 | 2011.05.07 | N12W03 | plage | |||||||
| S998 | 2011.05.08 | N15E30 |
 |
plage | ||||||
| S999 | 2011.05.09 | 2 | S14E78 | 0010 | BXO |
 |
||||
| Total spot count: | 33 | 64 | ||||||||
| Sunspot number: | 93 | 154 | ||||||||
| 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 |
| 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 | 16.7 (+0.3) | 6.31 / 5.15 |
| 2010.08 | 79.2 | 19.6 | 17.4 (+0.7) | 8.49 / 7.77 |
| 2010.09 | 81.1 | 25.2 | 19.6 (+2.2) | 5.33 / 5.45 |
| 2010.10 | 81.6 | 23.5 | 23.2 (+3.6) | 6.07 / 6.27 |
| 2010.11 | 82.5 | 21.5 | (26.9 predicted, +3.7) | 4.80 / 5.50 |
| 2010.12 | 84.2 | 14.4 | (30.1 predicted, +3.2) | 3.41 / 4.35 |
| 2011.01 | 83.6 | 19.1 | (33.1 predicted, +3.0) | 4.32 / 5.51 |
| 2011.02 | 94.6 | 29.4 | (35.6 predicted, +2.5) | 5.41 / 6.44 |
| 2011.03 | 115.0 | 56.2 | (37.9 predicted, +2.3) | 7.79 |
| 2011.04 | 112.6 | 54.4 | (40.8 predicted, +2.9) | 9.71 |
| 2011.05 | 105.0 (1) | 19.8 (2A) / 68.3 (2B) | (44.1 predicted, +3.3) | (8.72) |
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.
