Solar Terrestrial Activity Report

Last major update issued on March 9, 2011 at 05:10 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 8, 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 8.

Solar flux measured at 17h UTC on 2.8 GHz was 149.9 (the observations at 20 and 23h could not be used as they were enhanced by a long duration M1.4 event in region S891. Despite the presence of one valid measurement SWPC chose to estimate solar flux to 155). The planetary A index  was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.3). Three hour interval K indices: 21112112 (planetary), 21211211 (Boulder).

The background x-ray flux is at the class C2 level.

At midnight UTC the visible solar disk had 8 spotted regions.

Region 11164 returned to a quiet state, however, the region remains capable of producing a major flare.
Region 11166 was quiet and developed further adding many spots. There is some polarity intermixing, with no obvious magnetic delta structures. A major flare is possible.
Region 11169 developed slowly and could produce C flares.
New region 11170 emerged in the southwest quadrant on March 7 and was numbered the next day by NOAA/SWPC. Flare: C4.7 at 09:35 UTC.
New region 11171 emerged in an old plage area. Flare: M1.5 at 03:58 (associated with type II and IV radio sweeps and a CME off the east limb) UTC.

Spotted regions not numbered by NOAA/SWPC:
Region S891 rotated out of view at the southwest limb but is still the region with the highest flare potential. Flares: C4.7 at 00:19, M1.3/1N at 02:29, C5.5 at 05:08, major M5.3/1F at 10:44, M4.4 at 18:28, long duration M1.4 peaking at 20:17, C7.7 at 23:14 and C8.8 at 23:37 UTC.
[S896] Spots emerged in the northeast quadrant, just north of region 11166, on March 6. The region decayed slowly on March 8 and lost the trailing spot. Location at midnight: N16W07.
[S900] Tiny spots emerged in an old plage area in the southeastern quadrant on March 8. Location at midnight: S20E26.
[S901] This region emerged in the southwest quadrant on March 8. Location at midnight: S22W14.

Coronal mass ejections (CMEs)

March 6 and 8: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 7: A partial halo CME was observed following a long duration (LDE) event in region 11166. This CME could reach Earth on March 9/10, however, it will highly likely be overtaken by the very fast CME produced by the M3.7 LDE in region 11164 late in the day. This CME could reach Earth on March 9 and cause unsettled to major storm conditions.

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 major storm on March 9-10 due to CME effects. Mostly quiet conditions are likely on March 11.

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
11164 2011.02.25 23 27 N23W71 0580 EKC EKC beta-gamma-delta
11165 2011.02.26
2011.02.25
5   S18W92 0200 EKI     rotated out of view

SWPC has included S891 in this region

location: S23W89

11166 2011.03.02 35 67 N11W01 0550 FKC EHC beta-gamma

location: N08E02

11167 2011.03.02
2011.03.03
1   N13W36 0010 AXX    

spotless

location: N14W33

S891 2011.03.03     S17W95         rotated out of view
S893 2011.03.03     N20W43           plage
11169 2011.03.05
2011.03.06
11 32 N19E31 0170 DSO DAI

beta-gamma

S895 2011.03.05     N07W27           plage
S896 2011.03.06   2 N16W07 0010   AXX  
11170 2011.03.07
2011.03.08
2 9 S26W68 0030 BXO DRO formerly region S897
S898 2011.03.07     S13E24         plage
S899 2011.03.07     N19W17         plage
11171 2011.03.08   2 S19E69 0000   AXX   location of spots: S22E49
S900 2011.03.08   4 S20E26 0000   BXO    
S901 2011.03.08   1 S22W14 0000   AXX    
Total spot count: 77 144  
Sunspot number: 137 224  

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
2011.03 131.3 (1) 26.5 (2A) / 102.6 (2B) (33.0 predicted, +1.9) (11.89)

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.