Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 21, 2014 at 06:55 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 20. Solar wind speed at SOHO ranged between 284 and 340 km/s.

Solar flux at 20h UTC on 2.8 GHz was 151.3 (decreasing 5.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 152.9. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.5). Three hour interval K indices: 12221111 (planetary), 12122211 (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 16 active regions in 2K resolution (SN: 307) and 13 active regions in 1K resolution (SN: 216) SDO images on the visible solar disk.

Region 12004 [S10W66] decayed quickly and quietly
Region 12005 [N12W32] was quiet and stable.
Region 12008 [S11E04] was quiet and stable.
Region 12010 [S15E27] was mostly quiet and stable.
Region 12011 [S08W50] developed further and has two small magnetic delta structures in the largest penumbra. An M class flare is possible.
Region 12013 [N13E42] was quiet and stable.
Region 12014 [S13E60] decayed after the flares early in the day.
C5+ flares: C9.9 at 07:34, M1.7 at 03:57 (wrongly attributed to AR 12010 by SWPC) UTC. The M1 flare was associated with a CME off the east limb.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3226 [S10W06] was quiet and stable.
S3227 [S26W14] retained only a penumbra spot in the easternmost part of the trailing polarity.
S3233 [S27E17] was quiet and stable.
S3236 [S27E30] regained a leading polarity penumbra spot.
S3241 [N15E13] reemerged with penumbra spots.
S3245 [S18W09] decayed slowly and quietly.
New region S3248 [S01E72] rotated into view.
New region S3249 [S05W32] emerged with penumbra spots.
New region S3250 [N39E09] emerged with a penumbra spot at a high latitude.

Coronal mass ejections (CMEs)

March 18-20: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

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 small trans equatorial coronal hole (CH608) was in an Earth facing position on March 19-20.

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. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on March 21. Effects from CH608 could cause a weak disturbance on March 22-23.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% 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
12004 2014.03.09
2014.03.10
5 7 3 S10W73 0050 CAO CRO

location: S10W66

12005 2014.03.11
2014.03.12
1 11 7 N13W37 0250 HHX CHO images/AR_12005_20140320_2345.png images/AR_12005_20140319_2345.png area: 0320

location: N12W32

12007 2014.03.13
2014.03.14
      N11W19           trailing part of AR 12005
12009 2014.03.13
2014.03.16
      N14W58           plage

location: N11W58

12008 2014.03.14
2014.03.15
11 10 4 S11E03 0050 DAI BXO area: 0020

SWPC location is OK, however, they seem to be counting the spots of AR S3226.

S3225 2014.03.15       S14W00           plage
S3226 2014.03.15   28 16 S10W06 0090   DRI  
S3227 2014.03.15   1   S26W14 0004   AXX images/AR_S3227_20140319_2345.png  
S3229 2014.03.16       S08W28           plage
12010 2014.03.16
2014.03.17
16 36 18 S15E25 0130 DAI DAO

area: 0250

S3231 2014.03.16       S19W13           plage
S3232 2014.03.16       S24W17           plage
S3233 2014.03.17   2 2 S27E17 0008   AXX  
12012 2014.03.17
2014.03.18
      S09E33         plage
12013 2014.03.17
2014.03.18
1 3 1 N13E42 0030 HSX CSO area: 0070
S3236 2014.03.17   1 1 S27E30 0006   AXX  
S3237 2014.03.17       S23E01           plage
12011 2014.03.18 26 23 10 S07W50 0230 DAI DAC beta-gamma-delta

area: 0380

12014 2014.03.18
2014.03.19
7 13 7 S15E60 0140 DSO CAO

location: S13E60

S3241 2014.03.18   3 3 N15E13          
S3242 2014.03.18       N21W18           plage
S3244 2014.03.19       N17E28         plage
S3245 2014.03.19   3 1 S18W09 0009   BXO  
S3246 2014.03.19       S02W02         plage
S3248 2014.03.20   1 1 S01E72 0006   HRX    
S3249 2014.03.20   4 2 S05W32 0010   BXO    
S3250 2014.03.20   1   N39E09 0002   AXX    
Total spot count: 67 147 76  
Sunspot number: 137 307 216  (total spot count + 10 * number of spotted regions)
Weighted SN: 107 186 115  (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): 82 107 119 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
2014.03 149.2 (1)   93.1 (2A) / 144.3 (2B) / 118.3 (2C) (71.0 projected, +0.1) (4.5)

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.