Solar Terrestrial Activity Report

Last major update issued on July 2, 2012 at 05:05 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 unsettled to active on July 1. Solar wind speed at SOHO ranged between 570 and 735 km/s under the influence of a high speed stream from CH521.

Solar flux measured at 20h UTC on 2.8 GHz was 133.4 (increasing 5.2 over the last solar rotation). The Potsdam WDC planetary A index was 21 (STAR Ap - based on the mean of three hour interval ap indices: 21.1). Three hour interval K indices: 44433334 (planetary), 45433323 (Boulder).

The background x-ray flux is at the class B6 level.

At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11512 [S15W43] decayed slowly and quietly.
Region 11513 [N15E04] added several spots while the main penumbra became larger. There's significant polarity intermixing. Flares: C5.4 at 07:16, M2.8 at 19:18 UTC.
Region 11514 [S15E04] decayed quickly and lost all traces of penumbra.
Region 11515 [S17E18] developed further, particularly in the trailing and intermediate spot section. An elongated magnetic delta structure has formed in the central parts and a major flare is possible. Flare: C8.2 at 15:45 UTC
Region 11516 [N14E17] decayed slowly and quietly.
New region 11517 [N19E28] emerged on June 30 and developed quickly on July 1 when it was numbered by SWPC. C flares are possible.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1765 [S28W02] reemerged with tiny spots.
New region S1769 [N17E39] emerged with a single spot.
New region S1770 [N03E18] emerged with a tiny spot.
New region S1771 [S15W30] emerged with a single spot.

Coronal mass ejections (CMEs)

June 29 - July 1: 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 large recurrent trans equatorial coronal hole (CH521) was in an Earth facing position on June 28 - July 1. 

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 good.

Forecast

The geomagnetic field is expected to be unsettled to active on July 2, quiet to active on July 3 and quiet to unsettled on July 4-5 under the influence of a high speed stream from CH521.

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
S1745	2012.06.21				N20W49						plage
11512	2012.06.24 2012.06.25	5	8	4	S16W41	0130	CSO	DSO			area: 0180
S1753	2012.06.25				S27W11						plage
S1754	2012.06.25				S18W52						plage
11513	2012.06.25 2012.06.26	11	19	12	N16E03	0120	DAO	DHI			beta-gamma area: 0300 location: N15E04
11514	2012.06.26 2012.06.27	7	14	4	S15E02	0010	BXO	BXO			location: S15E04
11515	2012.06.26 2012.06.27	28	49	27	S17E17	0850	EKC	EKC			beta-gamma-delta area: 1000
S1758	2012.06.26				N14W41						plage
S1759	2012.06.26				N19W55						plage
S1760	2012.06.26				N06W57						plage
11516	2012.06.27 2012.06.29	8	9	6	N14E17	0040	CSO	DRO
S1762	2012.06.27				N03W14						plage
S1764	2012.06.29				N20W49						plage
S1765	2012.06.29		3		S28W02	0000		AXX
11517	2012.06.30 2012.07.01	18	25	11	N19E26	0170	DAO	DSI			beta-gamma
S1767	2012.06.30				N18E10
S1768	2012.06.30				N15W31						plage
S1769	2012.07.01		6	1	N17E39	0000		AXX
S1770	2012.07.01		1		N03E18	0000		AXX
S1771	2012.07.01		1	1	S15W30	0010		AXX
Total spot count:		77	135	66
Sunspot number:		137	235	146	(total spot count + 10 * number of spotted regions)
Weighted penumbral SN:		107	168	99	(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	82	80	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.