Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 8, 2012 at 07:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-24 (last update June 2, 2012)] [Cycle 24 progress NEW]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 2, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 2, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update July 1, 2012)]

[POES auroral activity level since October 2009 - updated July 2, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet to unsettled on July 7. Solar wind speed at SOHO ranged between 397 and 512 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 158.4 (increasing 30.1 over the last solar rotation). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.8). Three hour interval K indices: 22221132 (planetary), 22232323 (Boulder).

The background x-ray flux is at the class C2 level.

At midnight UTC the visible solar disk had 14 spotted active regions (in 2K resolution SDO images).

Region 11513 [N15W80] was quiet and unchanged.
Region 11515 [S17W66] decayed significantly losing many spots, some penumbral area and several magnetic delta structures. The region is still capable of producing a major flare.
Region 11517 [N18W54] decayed slowly and quietly.
Region 11518 [N09E26] developed slowly and quietly.
Region 11519 [S15E35] was quiet and stable.
New region 11520 [S17E62] rotated partly into view on July 5 and was numbered by SWPC two days later. The region is the largest on the visible disk, has a significant magnetic delta structure in the central part and is capable of producing a major flare.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1776
[S16E51] developed slowly and quietly.
S1777 [S12E59] was quiet and stable.
S1780 [S21W33] was quiet and stable.
New region S1781 [S16E43] emerged with a few spots.
New region S1782 [S23E43] emerged with a single spot.
New region S1783 [N13E48] emerged with a tiny spot.
New region S1784 [N25E03] emerged with a small spot.
New region S1785 [S26E26] emerged with tiny spots.

Coronal mass ejections (CMEs)

July 6: While the core CME associated with the X1 event in AR 11515 will not reach Earth, a flank impact is likely on July 9.
July 5 and 7
: 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 coronal hole (CH522] in the northern hemisphere was in an Earth facing position on July 6-7. 

Coronal hole map

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on July 8. Quiet to minor storm is possible on July 9-10 due to effects from the CME observed after the X1 event in AR 11515 on July 6 and a high speed stream from CH522.

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 higher resolution image) Compare to the previous day's image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) 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 STAR SDO SWPC STAR Current Previous
2K 1K
11513 2012.06.25
2012.06.26
2 1 1 N16W78 0180 HSX HHX

area: 0300

location: N15W80

11514 2012.06.26
2012.06.27
      S13W80          

plage

location: S18W73

11515 2012.06.26
2012.06.27
43 44 27 S17W63 0780 FKI FKC beta-gamma-delta

area: 1250

location: S17W66

11516 2012.06.27
2012.06.29
      N20W65           plage

location: N14W65

11517 2012.06.30
2012.07.01
3 4 2 N19W53 0020 CRO AXX area: 0000
S1767 2012.06.30       N20W63          
S1769 2012.07.01       N17W34         plage
11518 2012.07.03
2012.07.04
4 12 6 N10E24 0030 CRO DRO location: N09E26
11519 2012.07.04 1 1 1 S15E34 0070 HSX HSX  
S1774 2012.07.04       S26E38           plage
11520 2012.07.05
2012.07.06
14 43 24 S15E54 0510 FHC EKC beta-gamma-delta

location: S17E62

area: 1500

S1776 2012.07.05   13 7 S16E51 0040   DRI  
S1777 2012.07.05   1 1 S12E59 0080   HSX  
S1778 2012.07.05       S28W39           plage
S1779 2012.07.05       N15W23           plage
S1780 2012.07.06   4 3 S21W33 0000   BXO  
S1781 2012.07.07   3 3 S16E43 0010   BXO    
S1782 2012.07.07   1 1 S23E43 0000   AXX    
S1783 2012.07.07   1   N13E48 0000   AXX    
S1784 2012.07.07   1 1 N25E03 0000   AXX    
S1785 2012.07.07   4   S26E26 0000   AXX    
Total spot count: 67 133 77  
Sunspot number: 127 273 179  (total spot count + 10 * number of spotted regions)
Weighted penumbral SN: 103 179 123  (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): 76 96 98 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2008.07 65.7 (SF minimum) 0.5 2.8 (-0.4)  
2008.12 69.2 0.8 1.7 (-)
sunspot minimum
 
2011.04 112.6 54.4 41.8 (+4.9) 8.83
2011.05 95.8 41.6 47.6 (+5.8) 8.94
2011.06 95.8 37.0 53.2 (+5.6) 8.06
2011.07 94.2 43.9 57.2 (+4.0) 8.16
2011.08 101.7 50.6 59.0 (+1.8) 7.26
2011.09 133.8 78.0 59.5 (+0.5) 12.27
2011.10 137.3 88.0 59.9 (+0.4) 8.28
2011.11 153.5 96.7 61.1 (+1.2) 5.55
2011.12 141.3 73.0 63.4 (+2.3) 3.78
2012.01 132.5 58.3 (65.0 projected, +1.6) 7.15
2012.02 106.5 33.1 (66.5 projected, +1.5) 8.81
2012.03 114.7 64.2 (67.2 projected, +0.7) 16.08
2012.04 113.0 55.2 (66.5 projected, -0.7) 10.10
2012.05 121.5 69.0 (64.8 projected, -1.7) 7.06
2012.06 119.6 64.5 (64.0 projected, -0.8) 12.58
2012.07 147.9 (1) 30.5 (2A) / 135.3 (2B) (65.0 projected, +1.0) (16.25)

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 SIDC international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC ap indices.

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