Solar Terrestrial Activity Report

Last major update issued on March 6, 2011 at 05:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update March 2, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 2, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 2, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2011)]

[POES auroral activity level charts since October 2009 - updated March 4, 2011]
Annotated geomagnetic activity charts - Carrington rotation 2105 [Dec-Jan.2011] - 2106 [Jan.-Feb.2011] NEW

Recent activity

The geomagnetic field was quiet on March 5, still under the influence of a high speed stream from CH438.

Solar flux measured at 20h UTC on 2.8 GHz was 134.6 (increasing 54.4 over the last solar rotation and a new high for cycle 24). The planetary A index  was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.8). Three hour interval K indices: 12011121 (planetary), 13012211 (Boulder).

The background x-ray flux is at the class B8 level.

At midnight UTC the visible solar disk had 7 spotted regions.

Region 11164 developed further and currently has at least 2 magnetic delta structures. A major flare sometime over the next couple of days is likely. Flares: C1.0 at 12:41, C1.1 at 12:48, C1.4 at 20:10, C2.9 at 21:44 UTC.
Region 11165 added several tiny spots and was quiet.
Region 11166 developed slowly and could produce an M class flare. Currently there is only minor polarity intermixing.
Region 11167 was quiet and didn't change significantly.

Spotted regions not numbered by NOAA/SWPC:
[S891] This region emerged in the southwest quadrant on March 3 and has since been developing slowly. Polarities are mixed and further C class flaring is likely. A minor M class flare will become possible if there is further growth. Location at midnight: S17W54. SWPC seems to be regarding S891 and 11165 as a single region, this interpretation is not supported by SDO data. Flares: C2.2 at 01:10, C1.6 at 02:49, C1.2 at 05:22, C2.2 at 09:08, C1.4 at 10:17, C1.6 at 11:49, C1.2 at 12:10, C1.0 at 12:26, C1.3 at 13:41, C1.0 at 14:25 UTC.
[S894] This region rotated into view at the northeast limb early on March 5. Location at midnight: N20E73.
[S895] A small spot emerged in the northeast quadrant on March 5. Location at midnight: N07E12.

Coronal mass ejections (CMEs)

March 4-5: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 3: A partial halo CME was observed in LASCO and STEREO images after 05:30 UTC. There was no apparent filament eruption and the source of this CME appears to have been to the southeast of the center of the visible disk.

Coronal holes

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

No significant coronal holes are currently in or near an Earth facing position.

The darkest areas on the solar disk are likely coronal holes.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on March 6-7 due to possible effects from the CME observed on March 3, with a chance of some active intervals. On March 8 quiet conditions are likely.

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.

Active solar regions

(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
11163 2011.02.24     N17W51         location: N16W38
11164 2011.02.25 28 55 N24W34 0770 FKC FKC beta-gamma-delta
11165 2011.02.26
2011.02.25
14 13 S21W52 0160 BXO BXI location: S23W47

area: 0010

11166 2011.03.02 16 39 N10E41 0610 EKI EHC beta-gamma
11167 2011.03.02
2011.03.03
4 7 N14E05 0020 BXO BXO

location: N14E07

S891 2011.03.03   26 S17W54 0120   DAI beta-gamma
11168 2011.03.03
2011.03.04
2   N23W84 0030 HAX     rotated out of view
S893 2011.03.03     N20W04         plage
S894 2011.03.05   4 N20E73 0020   BXO    
S895 2011.03.05   1 N07E12     AXX    
Total spot count: 64 145  
Sunspot number: 114 215  

Monthly solar cycle data

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
2011.03 121.2 (1) 14.3 (2A) / 88.8 (2B) (33.0 predicted, +1.9) (15.05)

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.