Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 24, 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 157.0 (decreasing 13.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.5. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 22212122 (planetary), 12222322 (Boulder).

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

At the time of counting spots (see image time), spots were observed in 14 active regions in 2K resolution (SN: 310) and 13 active regions in 1K resolution (SN: 219) SDO images on the visible solar disk.

Region 12005 [N12W73] was mostly unchanged and quiet.
Region 12008 [S10W32] decayed slowly and quietly.
Region 12010 [S13W13] developed slowly and produced several low level C flares. The region has two magnetic delta structures. An M class flare is possible.
Region 12012 [S16E05] lost the leader spot.
Region 12013 [N15E03] was quiet and stable.
Region 12014 [S12E21] developed and has polarity intermixing. A minor M class flare is possible.
C5+ flare: C5.0 long duration event peaking at 03:48 UTC. This event was associated with an asymmetric full halo CME.
Region 12015 [S14W42] developed a magnetic delta structure. A minor M class flare is possible.
Region 12016 [S27W07] decayed early in the day, then began to develop again in leading polarity.
Region 12017 [N10E47] gained penumbral area and appears to be maturing. Several low level C flares were recorded.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3226 [S10W47] decayed slowly and quietly. SWPC has moved AR 12008 14 degrees to the west of where it should be to include the spots in ARs S3226 and S3258, the original AR 12008 still has spots.
S3244 [N16W09] reemerged with a penumbra spot.
S3248 [N01E31] was quiet and stable.
S3258 [S05W47] decayed slowly and quietly.
New region S3259 [S20E52] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

March 21: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 22: A partial halo CME was observed after the LDE in AR 12005, it is uncertain if this CME has Earth directed extensions.
March 23: An asymmetric full halo CME was observed after the C5 LDE in AR 12014. The CME could reach Earth on March 26.

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

Forecast

The geomagnetic field is expected to be quiet on March 24-25 with some uncertainty on March 25 due to possible effects from the March 22 CME. Quiet to active conditions are possible on March 26 due to CME effects.

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 2 1 N12W74 0160 HSX CHO area: 0260
12007 2014.03.13
2014.03.14
      N11W61           trailing part of AR 12005
12008 2014.03.14
2014.03.15
6 3 1 S07W47 0030 CRO BXO area: 0012

SWPC has moved the region 14 degrees to the west and currently counts the spots of ARs S3226 and S3258.

real location: S10W32

12015 2014.03.15
2014.03.22
4 4 2 S14W42 0090 CAO DAC beta-delta

area: 0100

S3226 2014.03.15   8 4 S10W47 0022   CRO  
S3227 2014.03.15       S26W53           plage
12010 2014.03.16
2014.03.17
26 55 27 S15W13 0180 DAC DKC

beta-gamma-delta

area: 0440

location: S13W13

S3231 2014.03.16       S19W52           plage
S3232 2014.03.16       S24W56           plage
S3233 2014.03.17       S27W22           plage
12012 2014.03.17
2014.03.18
  5 3 S09W09 0016   AXX location: S16E05
12013 2014.03.17
2014.03.18
2 17 11 N14E03 0020 CAO CAO area: 0060
12016 2014.03.17
2014.03.22
1 6 4 S28W07 0010 AXX CRO area: 0020
S3237 2014.03.17       S23W38           plage
12011 2014.03.18 4     S06W92 0110 CAO    

rotated out of view

12014 2014.03.18
2014.03.19
16 45 23 S14E20 0170 DSC DSC

location: S12E21

area: 0370

S3241 2014.03.18       N14W26           plage
S3242 2014.03.18       N21W57           plage
S3244 2014.03.19       N17W11           plage
S3245 2014.03.19       S18W48           plage
S3246 2014.03.19       S02W41           plage
S3248 2014.03.20   5 2 N01E31 0012   BXO  
S3250 2014.03.20       N39W30           plage
12017 2014.03.21
2014.03.22
9 16 9 N09E45 0100 DAI DAO beta-gamma

area: 0200

S3254 2014.03.21       S02W20           plage
S3255 2014.03.22       S12E43         plage
S3256 2014.03.22       S08E39         plage
S3258 2014.03.22   2   S05W47 0004   AXX  
S3259 2014.03.23   1 1 S20E52 0006   AXX    
Total spot count: 69 169 89  
Sunspot number: 159 309 219  (total spot count + 10 * number of spotted regions)
Weighted SN: 107 215 135  (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): 95 108 120 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
2014.03 149.9 (1)   107.4 (2A) / 144.7 (2B) / 120.7 (2C) (71.0 projected, +0.1) (4.7)

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.