Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 10, 2015 at 04:40 UT.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update March 1, 2015)] [Cycle 24 progress (last update March 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2015)]

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated February 21, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on March 9. Solar wind speed at SOHO ranged between 371 and 512 km/s.

Solar flux at 20h UTC on 2.8 GHz was 122.9 (decreasing 18.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 137.8. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 32001101 (planetary), 32002211 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 138) and 5 active regions using 1K resolution (SN: 92) SDO images on the visible solar disk.

Region 12296 [S12W11] was quiet and stable.
Region 12297 [S16E43] developed further and has multiple magnetic deltas. An X class flare is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4256 [S13W53] was quiet and stable.
S4262 [N13W12] decayed slowly and quietly.
S4270 [S26W02] was quiet and stable.
New region S4273 [N11E60] emerged with a penumbra spot.
New region S4274 [S04W06] emerged with penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C3.0 00:15   12297 C2.7 according to SDO/EVE/ESP XRS-B proxy
C2.9/1F 06:02 S14E48 12297 Two events in XRS-B: C3.0 at 05:52, C3.3 at 06:02
C4.0/1N 10:08 S14E50 12297 XRS-B: C3.7 @ 10:10
M4.5/1N 14:33 S16E49 12297 XRS-B: M4.0 @ 14:33
C9.1/1N 17:42 S13E46 12297 XRS-B: C8.9 @ 17:42
M5.8/2N 23:53 S18E45 12297 XRS-B: M6.6 @ 23:55

Coronal mass ejections (CMEs)

March 8-9: No obviously Earth directed CMEs were observed in LASCO imagery.
March 7: At least a partial halo CME was associated with the M9 event in AR 12297.

Coronal holes

[Coronal hole history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]

A recurrent coronal hole (CH658) will rotate across the central meridian on March 9-10, CH658 has not been associated with geomagnetic disturbances during previous rotations.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over 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 10-12. While the core of the CME observed on March 7 will not reach Earth, there is a chance that weak extensions of the CME could cause unsettled and active intervals on March 10-11.

Coronal holes (1) Coronal mass ejection (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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.

Active solar regions

(Click on image for 2K resolution) Compare to the previous day's image. 0.5K image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue 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 magnetic polarity overlay
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12296 2015.03.02
2015.03.06
  6 4 S11W18 0020   AXX location: S12W11
S4255 2015.03.02       N17W51            
S4256 2015.03.02   1 1 S13W53 0004   AXX  
S4262 2015.03.04   3   N13W12 0004   AXX  
S4265 2015.03.05       S27W18            
S4266 2015.03.05       S44W19            
12297 2015.03.06 19 42 28 S16E39 0260 DAC DKC beta-gamma-delta

area: 0560

location: S16E43

S4270 2015.03.06   13 8 S26W02 0035   BXO images/AR_S4270_20150309_2345.png  
S4271 2015.03.07       S01W28            
S4272 2015.03.08       S15E09          
S4273 2015.03.09   1 1 N11E60 0004   AXX    
S4274 2015.03.09   2   S04W06 0003   BXO    
Total spot count: 19 68 42  
Sunspot number: 29 138 92  (total spot count + 10 * number of spotted regions)
Weighted SN: 24 78 52  (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number): 17 48 51 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1)
(likely solar max)
7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 79.7 (-0.8) 6.72
2014.07 137.4 141.8 72.5 78.6 (-1.1) 4.50
2014.08 124.7 127.9 74.7 75.6 (-3.0) 7.71
2014.09 146.6 148.1 87.6 (71.6 projected, -4.0) 9.78
2014.10 153.4 152.9 60.6 (69.2 projected, -2.4) 8.96
2014.11 154.8 151.4 70.1 (67.4 projected, -1.8) 9.33
2014.12 158.7 153.8 78.0 (66.3 projected, -1.1) 11.24
2015.01 141.9 137.3 67.0 (65.1 projected, -1.2) 9.46
2015.02 129.1 126.0 44.8 (63.6 projected, -1.5) 9.92
2015.03 (127.4)   11.4 (2A) / 39.1 (2B) / 56.3 (2C) (61.6 projected, -2.0) (13.6)

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 WDC-SILSO international sunspot number is typically 30-50% lower. 2B) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international GFZ Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on the 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.