Solar Terrestrial Activity Report

Last major update issued on January 10, 2013 at 06:05 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update January 1, 2013)] [Cycle 24 progress (last update January 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 2, 2013)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated January 8, 2013]

Recent activity

The geomagnetic field was very quiet on January 9. Solar wind speed at SOHO ranged between 306 and 321 km/s, weakly under the influence of a low speed stream from CH549.

Solar flux measured at 20h UTC on 2.8 GHz was 169.3 (increasing 52.7 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.6). Three hour interval K indices: 11010011 (planetary), 11112111 (Boulder).

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

At midnight UTC the visible solar disk had 15 spotted active regions (in 2K resolution SDO images).

Region 11642 [S24W41] was quiet and stable.
Region 11644 [N15W31] was quiet and stable.
Region 11646 [N13W20] decayed slowly and quietly.
Region 11648 [N07W16] was quiet and stable.
Region 11649 [S15E07] was quiet and stable.
Region 11650 [S29E14] decayed slowly and quietly.
Region 11651 [N22W13] reemerged with tiny spots.
Region 11652 [N20E25] developed in the leading spot section and has a small magnetic delta structure in the southern part of the leader spot.
Region 11653 [N08E21] was quiet and stable.
Region 11654 [N08E60] has major flare potential. There are currently no obvious magnetic delta structures. Interestingly both the large leading and trailing penumbrae have narrow interior opposite polarity flux channels.
New region 11655 [S21E03] emerged on January 8 and was numbered by SWPC the next day.

Spotted regions not numbered by SWPC:
New region S2167 [S33E42] emerged with a tiny spot.
New region S2168 [N11E39] emerged with a tiny spot.
New region S2169 [N22E82] rotated into view with small spots.
New region S2170 [S13E01] emerged with several spots.

Coronal mass ejections (CMEs)

January 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

No obvious coronal holes are currently in or near Earth facing positions.

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

Forecast

The geomagnetic field is expected to be quiet on January 10-12.

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 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 (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
11641	2012.12.29 2012.12.31				N02W74						plage
11642	2012.12.30 2012.12.31	1	3	2	S25W41	0050	HSX	CSO			area: 0140
11643	2012.12.31 2013.01.02				S14W53
11644	2013.01.01 2013.01.02	1	2	2	N13W31	0020	HAX	HAX
11648	2013.01.02 2013.01.04	3	3	1	N05W14	0010	AXX	AXX			location: N07W16
11646	2013.01.02 2013.01.03		4		N13W23	0000		AXX
11651	2013.01.02 2013.01.04		4		N20W19	0000		BXO			location: N22W13
11645	2013.01.02 2013.01.03	2			S14W85	0030	CRO				plage
11649	2013.01.03 2013.01.04	1	3	2	S15E05	0070	HSX	CSO			area: 0140
S2156	2013.01.03				N17W20						plage
11650	2013.01.04	7	11	4	S30E16	0100	EAO	ESO			location: S29E14 area: 0200
11652	2013.01.05	18	47	28	N19E25	0200	EAC	EAI			beta-gamma-delta area: 0350
11653	2013.01.05	2	3	1	N09E21	0020	CSO	HRX
S2157	2013.01.05				S02W23						plage
S2159	2013.01.05				N25W46						plage
S2160	2013.01.06				S18W29						plage
11654	2013.01.07	15	24	15	N10E60	0350	EKI	EKI			location: N08E60 area: 1000
S2162	2013.01.07				N20W01						plage
S2163	2013.01.07				S17W16						plage
S2164	2013.01.08				S17E51						plage
11655	2013.01.08 2013.01.09	3	10	6	S22W02	0010	BXO	CRO			area: 0040 location: S21E03
S2166	2013.01.08				N27W35						plage
S2167	2013.01.09		1		S33E42	0000		AXX
S2168	2013.01.09		1	1	N11E39	0000		AXX
S2169	2013.01.09		2	1	N22E82	0010		BXO
S2170	2013.01.09		4	4	S13E01	0010		BXO
Total spot count:		53	122	67
Sunspot number:		153	272	187	(total spot count + 10 * number of spotted regions)
Weighted SN:		96	163	111	(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):		92	95	103	k * (sunspot number). k = 0.6 for SWPC, k = 0.35 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) 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 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.