Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 4, 2015 at 04:45 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2015)] [Cycle 24 progress (last update February 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 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 January 25, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to active on February 3. Solar wind speed at SOHO ranged between 470 and 707 km/s under the slowly decreasing influence of a high speed stream.

Solar flux at 20h UTC on 2.8 GHz was 149.3 (increasing 2.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.5. The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 13.6). Three hour interval K indices: 44322232 (planetary), 34322333 (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 10 active regions using 2K resolution (SN: 240) and 8 active regions using 1K resolution (SN: 153) SDO images on the visible solar disk.

Region 12272 [N15W40] decayed slowly and quietly.
Region 12277 [N08W03] gained a few spots. There's significant polarity intermixing in the leading spot section. An M1.2 flare was recorded at 02:15 UTC on February 4 in that section. Another minor M class flare is possible.
Region 12278 [S07W39] lost the leading polarity spots and gained a few trailing polarity penumbra spots.
Region 12279 [S19W78] decayed slowly and quietly.
Region 12280 [S07E41] developed slowly and was mostly quiet.
New region 12281 [N12E78] rotated into view.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4186 [S17E01] was quiet and stable.
S4192 [S08E27] was quiet and stable.
New region S4195 [N09E26] emerged with penumbra spots.
New region S4196 [N15E32] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C2.7 09:47 S11E52 12280  
C3.9/1F 10:53 N06W03 12277  
C2.1 22:58 N07W09 12277  

Coronal mass ejections (CMEs)

February 1-3: No obviously Earth directed CMEs were observed in LASCO 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 poorly defined trans equatorial extension of a northern hemisphere coronal hole could rotated across the central meridian on February 5-6.

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 fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on February 4-6.

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
12268 2015.01.21
2015.01.22
12     S11W85 0220 FAI      

rotated out of view

real location: S09W91

SWPC data not in accordance with observations, copied from previous day

12278 2015.01.25
2015.01.29
  4   S08W46 0004   AXX location: S07W39
12272 2015.01.25
2015.01.26
  2 1 N13W50 0006   AXX  
12276 2015.01.27
2015.01.28
      S07W61           plage
12277 2015.01.27
2015.01.28
36 85 49 N09W06 0440 FKO FAI beta-gamma

location: N08W03

S4186 2015.01.30   8 2 S17E01 0015   BXO images/AR_S4186_20150203_2345.png images/AR_S4186_20150202_2345.png  
12279 2015.01.31
2015.02.02
3 2 1 S21W71 0030 CRO CRO location: S19W78
S4191 2015.02.01       N36E15         plage
S4192 2015.02.01   9 6 S08E27 0020   AXX  
12280 2015.02.02 10 22 9 S06E42 0080 DAI DAI beta-gamma

area: 0110

12281 2015.02.03 1 4 4 N13E75 0060 CAO DAO   area: 0160
S4195 2015.02.03   3 1 N09E26 0007   BXO    
S4196 2015.02.03   1   N15E32 0002   AXX  

 

Total spot count: 62 140 73  
Sunspot number: 112 240 153  (total spot count + 10 * number of spotted regions)
Weighted SN: 90 158 91  (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): 67 84 84 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
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
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 (76.2 projected, -2.4) 7.71
2014.09 146.6 148.1 87.6 (73.0 projected, -3.2) 9.78
2014.10 153.4 152.9 60.6 (70.5 projected, -2.5) 8.96
2014.11 154.8 151.4 70.1 (68.8 projected, -1.7) 9.33
2014.12 158.7 153.8 78.0 (67.7 projected, -1.1) 11.24
2015.01 141.9 137.3 67.0 (66.5 projected, -1.2) 8.9
2015.02 147.4 (1)   15.9 (2A) / 111.5 (2B) / 78.8 (2C) (64.9 projected, -1.6) (15.8)

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.