Solar Terrestrial Activity Report

Last major update issued on July 7, 2012 at 07:10 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 active on July 6. Solar wind speed at SOHO ranged between 421 and 522 km/s..

Solar flux measured at 20h UTC on 2.8 GHz was 157.7 (increasing 29.4 over the last solar rotation and the highest flare unenhanced solar flux in 2012). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.4). Three hour interval K indices: 23222344 (planetary), 23322334 (Boulder).

The background x-ray flux is at the class C3 level.

At midnight UTC the visible solar disk had 11 spotted active regions (in 2K resolution SDO images).

Region 11513 [N15W65] was mostly quiet and unchanged.
Region 11515 [S17W52] is a large and complex region region with strong polarity intermixing and many magnetic delta structures. The region produced its first X class event which currently is associated with a minor proton event. Further major flare are possible and more significant proton flares are possible as the region approaches the southwest limb. Flares: C6.8/1N at 00:21, M2.9 at 01:40 C5.0/1N at 02:31, M1.0 at 02:51, C5.8 at 04:33, C7.4 at 07:07, M1.5 at 08:23, M1.8/1N at 10:29, M1.2 at 13:30, C5.0 at 16:05, C7.2 at 17:43, impulsive major X1.1 at 23:08 and M2.0 at 23:28 UTC. The X1.1 event was associated with a partial halo CME (in LASCO images, STEREO-A displays a full halo CME).
Region 11517 [N18W38] decayed slowly and quietly.
Region 11518 [N09E37] decayed slowly and quietly.
Region 11519 [S15E49] was quiet and stable.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1767 [N20W50] decayed losing all but one spot. SWPC has decided that spotless AR 11516 suddenly moved northwards and assigned this spot to that AR.
S1769 [N17W21] decayed slowly and quietly.
S1775 [S18E74] rotated fully into view revealing a complex region with a huge central penumbra. That penumbra has a strong magnetic delta structure. X class flares are possible, however, this region is much less active flarewise than AR11515 and may release significantly more energy in the case of a major flare event. Flare: C7.7 at 04:59 UTC. This event was wrongly attributed to AR 11515 by SWPC, not surprising since they somehow managed to overlook this large region.
S1776 [S15E62] was quiet and stable.
S1777 [S13E76] was quiet and stable. This region can be interpreted as being part of AR S1775.
New region S1780 [S22W19] emerged with a few tiny spots and came close to developing rudimentary penumbra by the end of the day.

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: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 4: A weak CME observed after an M1 flare in AR 11513 could reach Earth on July 7.

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 could rotate into an Earth facing position on July 6-7. 

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 fair.

Forecast

The geomagnetic field is expected to be quiet to active on July 7-8 with a chance of occasional minor storm intervals due to the recent CMEs from ARs 11515 and 11513. Unsettled to major storm is possible from the latter half of July 8 until July 10 due to effects from the CME observed after the X1 event in AR 11515 on July 6.

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	3	1	N15W65	0180	HSX	HHX			area: 0300
11514	2012.06.26 2012.06.27				S13W67						location: S18W62
11515	2012.06.26 2012.06.27	60	89	40	S18W50	0900	FHC	FKC			gamma-delta area: 1500 location: S17W52
11516	2012.06.27 2012.06.29	2			N20W52	0000	AXX				plage location: N14W52 SWPC has included AR S1767 in this region
11517	2012.06.30 2012.07.01	3	8	2	N19W39	0030	CRO	BXO			area: 0010
S1767	2012.06.30		1		N20W50	0000		AXX
S1769	2012.07.01		4		N17W21	0000		AXX
S1770	2012.07.01				N03W48						plage
11518	2012.07.03 2012.07.04	3	6	4	N09E39	0050	CSO	CRO			area: 0030
11519	2012.07.04	1	3	1	S15E47	0080	HSX	HSX
S1774	2012.07.04				S26E51						plage
S1775	2012.07.05		35	16	S18E74	1200		FKC			beta-gamma-delta
S1776	2012.07.05		2	1	S15E62	0010		BXO
S1777	2012.07.05		4	3	S13E76	0230		DSO
S1778	2012.07.05				S28W26						plage
S1779	2012.07.05				N15W10						plage
S1780	2012.07.06		4	1	S22W19	0010		BXO
Total spot count:		71	159	69
Sunspot number:		131	269	159	(total spot count + 10 * number of spotted regions)
Weighted penumbral SN:		99	202	112	(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	94	87	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

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.