Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 25, 2014 at 04:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update March 1, 2014)] [Cycle 24 progress (last update March 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2014)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated March 16, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on March 23. Solar wind speed at SOHO ranged between 402 and 524 km/s, weakly under the influence of a high speed stream from CH608.

Solar flux at 20h UTC on 2.8 GHz was 158.6 (decreasing 15.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.9. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.3). Three hour interval K indices: 20111110 (planetary), 21113311 (Boulder).

The background x-ray flux is at the class B6 level.

At the time of counting spots (see image time), spots were observed in 14 active regions in 2K resolution (SN: 325) and 13 active regions in 1K resolution (SN: 230) SDO images on the visible solar disk.

Region 12008 [S12W43] decayed slowly and quietly.
Region 12010 [S13W25] decayed slowly and has a weak magnetic delta structure in the southern part of the largest penumbra. An M class flare is possible.
Region 12012 [S14W12] regained a leader spot.
Region 12013 [N15W11] decayed slowly and quietly.
Region 12014 [S12E07] developed slowly early in the day. The region has polarity intermixing and could produce a minor M class flare.

Region 12015 [S13W55] has a weak magnetic delta structure. A minor M class flare is possible.
Region 12016 [S27W20] was quiet and stable.
Region 12017 [N10E34] was quiet and stable.
New region 12018 [N03E39] emerged with several spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3226 [S09W57] decayed slowly and quietly.
S3248 [N01E15] was quiet and stable.
S3255 [S12E27] reemerged with penumbra spots.
New region S3261 [S12E70] rotated into view with penumbra spots.
New region S3262 [S10E42] emerged with penumbra spots.

Coronal mass ejections (CMEs)

March 24: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 23: An asymmetric full halo CME was observed after the C5 LDE in AR 12014. The CME could reach Earth on March 26.
March 22: A partial halo CME was observed after the LDE in AR 12005, it is uncertain if this CME has Earth directed extensions.

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

No obvious coronal holes are currently in or near Earth facing positions.

Coronal hole map

Propagation

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

Forecast

The geomagnetic field is expected to be quiet on March 25, there is a chance of unsettled intervals should the CME observed on March 22 reach Earth. Quiet to active conditions are possible on March 26 due to CME effects with quiet conditions likely on March 27.

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
12005 2014.03.11
2014.03.12
1     N13W86 0080 HAX     rotated out of view
12007 2014.03.13
2014.03.14
      N11W75           trailing part of AR 12005
12008 2014.03.14
2014.03.15
  2 1 S07W61 0007   BXO

SWPC has moved the region many degrees to the west

real location: S12W43

12015 2014.03.15
2014.03.22
2 2 2 S12W55 0060 DAC DAC beta-delta
S3226 2014.03.15   2   S09W57 0004   AXX  
12010 2014.03.16
2014.03.17
22 53 32 S14W27 0230 DAC DAC

beta-gamma-delta

area: 0320

location: S13W25

S3233 2014.03.17       S27W35           plage
12012 2014.03.17
2014.03.18
  4 1 S09W23 0016   BXO location: S14W12
12013 2014.03.17
2014.03.18
1 8 3 N15W11 0010 HRX CRO area: 0025
12016 2014.03.17
2014.03.22
1 4 3 S28W21 0010 AXX CRO area: 0015
S3237 2014.03.17       S23W51           plage
12014 2014.03.18
2014.03.19
16 61 30 S13E08 0210 ESC ESC

location: S12E07

area: 0420

S3241 2014.03.18       N14W39           plage
S3244 2014.03.19       N17W24           plage
S3246 2014.03.19       S02W54           plage
S3248 2014.03.20   6 2 N01E15 0012   BXO  
12017 2014.03.21
2014.03.22
6 25 16 N12E33 0130 DAO DAI beta-gamma

area: 0260

S3254 2014.03.21       S02W33           plage
S3255 2014.03.22   2 2 S12E27 0008   AXX    
S3256 2014.03.22       S08E26           plage
S3259 2014.03.23       S20E39         plage
12018 2014.03.24 3 9 5 N03E38 0010 BXO DRO   area: 0040
S3261 2014.03.24   2 1 S12E70 0005   AXX    
S3262 2014.03.24   5 2 S10E40 0010   BXO    
Total spot count: 52 185 100  
Sunspot number: 132 325 230  (total spot count + 10 * number of spotted regions)
Weighted SN: 80 214 129  (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): 79 114 127 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
2012.11 121.3 118.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 105.0 40.8 59.6 (-0.1) 3.44
2013.01 127.1 123.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 101.8 38.0 58.4 (-0.3) 6.11
2013.03 111.3 110.2 57.9 57.5 (-0.9) 10.56
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 (72.8 projected, +3.8) 5.23
2013.10  132.1 131.2 85.6 (73.8 projected, +1.0) 7.71
2013.11  148.3 145.1 77.6 (72.7 projected, -1.1) 5.68
2013.12 147.7 143.1 90.3 (71.6 projected, -1.1) 4.68
2014.01 157.4 152.4 82.0 (71.6 projected, 0.0) 5.44
2014.02 170.3
(cycle peak)
166.3 102.8 (cycle peak) (70.9 projected, -0.7) 10.70
2014.03 150.3 (1)   111.6 (2A) / 144.2 (2B) / 120.6 (2C) (71.0 projected, +0.1) (4.6)

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.