Solar Terrestrial Activity Report

Last major update issued on July 10, 2012 at 05:25 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 active to major storm on July 9. Solar wind speed at SOHO ranged between 352 and 545 km/s, highly likely under the influence of CME effects from the X1 event on July 6.

Solar flux measured at 20h UTC on 2.8 GHz was 173.8 (increasing 32.5 over the last solar rotation). The Potsdam WDC planetary A index was 42 (STAR Ap - based on the mean of three hour interval ap indices: 42.5). Three hour interval K indices: 54446545 (planetary), 44335434 (Boulder).

The background x-ray flux is at the class C1 level.

At midnight UTC the visible solar disk had 12 spotted active regions (in 2K resolution SDO images).

Region 11515 [S16W87] rotated mostly out of view with only a single penumbra visible at the southwest limb at the end of the day. Flares: C7.9 at 08:30, C6.5 at 09:32, C5.0 at 19:52 UTC.
Region 11518 [N09E01] decayed slowly and quietly.
Region 11519 [S16E09] decayed slowly ad quietly.
Region 11520 [S17E36] did not change signficiantly ad remains a large and compact region with a huge main penumbra spanning almost 8 degrees longtitudinally and 5 degrees latitudinally. The central part of the main penumbra has a magnetic delta structure. A major flare is possible. Flares: impulsive M1.1 at 23:07 UTC and several C flares.
New region 11521 [S22E20] emerged on July 7 and was noticed by SWPC two days later. The region is developing and could produce at least C flares.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1776 [S16E26] developed further and could produce minor M class flares.
S1777 [S12E32] quietly added some tiny spots.
S1781 [S16E16] decayed significantly and was quiet.
S1783 [N13E22] was quiet and stable.
S1785 [S28E07] decayed slowly and quietly.
New region S1788 [N02W10] emerged near the equator.
New region S1789 [N08W33] emerged with a tiny spot.

Coronal mass ejections (CMEs)

July 7-9: 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. 

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

Forecast

The geomagnetic field is expected to be quiet to minor storm on July 10 due to CME and coronal hole effects. Quiet to active is likely on July 11 becoming quiet to unsettled on July 12-13.

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
11515	2012.06.26 2012.06.27	7	1	1	S15W89	0320	DAO	HSX
11517	2012.06.30 2012.07.01				N19W81						plage
11518	2012.07.03 2012.07.04	4	10	3	N10W00	0010	BXO	BXO			location: N09E01
11519	2012.07.04	8	2	2	S16E13	0100	CSO	CSO
S1774	2012.07.04				S26E12						plage
11520	2012.07.05 2012.07.06	57	57	27	S17E33	1320	FKC	EKC			beta-gamma-delta location: S17E36 area: 1700 SWPC count and area probably includes ARs S1776 and S1777
S1776	2012.07.05		41	19	S16E26	0450		DKI
S1777	2012.07.05		8	2	S12E32	0100		HSX
S1779	2012.07.05				N15W49						plage
S1780	2012.07.06				S21W59						plage
S1781	2012.07.07		10	5	S16E16	0010		BXO
11521	2012.07.07 2012.07.09	11	28	15	S22E21	0110	DAO	DAI			beta-gamma
S1783	2012.07.07		8	1	N13E22	0000		AXX
S1784	2012.07.07				N25W23						plage
S1785	2012.07.07		3	2	S28E07	0000		AXX
S1786	2012.07.08				S20W64						plage
S1787	2012.07.08				S20W09
S1788	2012.07.09		1	1	N02W10	0000		AXX
S1789	2012.07.09		1		N08W33	0000		AXX
Total spot count:		87	170	78
Sunspot number:		137	290	188	(total spot count + 10 * number of spotted regions)
Weighted penumbral SN:		112	210	118	(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	102	103	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.