Solar Terrestrial Activity Report

Last major update issued on March 8, 2011 at 05:30 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update March 2, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 2, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 2, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2011)]

[POES auroral activity level charts since October 2009 - updated March 4, 2011]
Annotated geomagnetic activity charts - Carrington rotation 2105 [Dec-Jan.2011] - 2106 [Jan.-Feb.2011] NEW

The geomagnetic field was quiet to active on March 7. The CME observed on March 3 was absorbed into the solar wind with weak effects observed on March 6 and stronger effects on March 7 as the interplanetary magnetic field was predominantly southwards.

Solar flux measured at 17h UTC on 2.8 GHz was 151.9 (the observation at 20h could not be used because of the strong influence from the M3.7 LDE - increasing 62.2 over the last solar rotation and a new high for cycle 24). The planetary A index  was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.8). Three hour interval K indices: 21023243 (planetary), 22133232 (Boulder).

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

At midnight UTC the visible solar disk had 10 spotted regions.

Region 11164 finally began to produce M flares. A major proton flare is possible before the region rotates over the northwest limb. Flares: M1.2/1F at 05:13, M1.4/1F at 08:05, M1.8 at 09:20, C4.9 at 10:21, long duration M3.7 event peaking at 20:12 (with an associated strong type II radio sweep and a very fast full halo CME) UTC. The latter event was a minor proton flare as well.
Region 11165 decayed slowly and was quiet. Observe that NOAA/SWPC has included S891 in this region.
Region 11166 began to develop again and has doubled its spot number in one day. A major flare is possible. Flares: long duration M1.9 event (associated with a partial halo CME) peaking at 14:30 UTC
Region 11167 decayed slowly and could soon become spotless.
Region 11169 developed slowly and could produce C flares.

Spotted regions not numbered by NOAA/SWPC:
[S891] This region emerged in the southwest quadrant on March 3 and developed slowly the first days. Rapid development was observed on March 6 with many new spots emerging and at least 2 magnetic delta structures forming. On March 7 most of the spots merged into two large penumbrae. The trailing penumbra is very complex with a strong magnetic delta structure. A major flare is possible. Location at midnight: S17W82. Flares: C3.0 at 02:12, C5.0 at 04:39, C3.6 at 07:18, M1.5 at 07:54, C5.1 at 16:09, C7.6 at 18:23, M1.5 at 21:50 UTC.
[S896] Spots emerged in the northeast quadrant, just north of region 11166, on March 6. No significant changes were observed on March 7. Location at midnight: N16E09.
[S897] This region emerged on March 7 in the southwest quadrant. Location at midnight: S26W53
[S898] A tiny spot emerged in the southeast quadrant on March 7. Location at midnight: S13E37
[S899] A new region emerged in the northern hemisphere near the central meridian on March 7. Location at midnight: N19W04

Early on March 8 region S891 produced an M1.3/1N flare at 02:29 while a spotless plage region near the southeast limb was the source of a long duration M1.5 event (which was associated with a CME off the east limb) peaking at 03:58 UTC.

March 5-6: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 7: A partial halo CME was observed following a long duration (LDE) event in region 11166. This CME could reach Earth on March 9/10, however, it will very likely be overtaken by the very fast CME produced by the M3.7 LDE in region 11164 late in the day. This CME could reach Earth on March 9 and cause minor to severe geomagnetic storming.

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

No significant coronal holes are currently in or near an Earth facing position.

The darkest areas on the solar disk are likely coronal holes.

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.

The geomagnetic field is expected to be quiet to unsettled on March 8. A CME will likely arrive on March 9 and cause unsettled to major storm conditions, possibly with severe storming, that day and on March 10.

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 polarity overlay		Comment
		SWPC	STAR SDO			SWPC	STAR	Current	Previous
11164	2011.02.25	20	43	N24W59	0760	EKC	EKC			beta-gamma-delta
11165	2011.02.26 2011.02.25	18	6	S20W78	0420	FKO	HAX			location: S23W76 area: 0030 SWPC has included S891 in this region
11166	2011.03.02	25	56	N11E12	0410	EKC	EHC			beta-gamma location: N09E15
11167	2011.03.02 2011.03.03	2	3	N15W18	0010	BXO	BXO			location: N14W20
S891	2011.03.03		24	S17W82	0500		EKC			beta-gamma-delta
S893	2011.03.03			N20W30						plage
11169	2011.03.05 2011.03.06	7	19	N20E44	0050	DSI	DAI			beta-gamma
S895	2011.03.05			N07W14						plage
S896	2011.03.06		3	N16E08	0020		CRO
S897	2011.03.07		4	S26W53	0010		CRO			beta-gamma
S898	2011.03.07		1	S13E37	0000		AXX
S899	2011.03.07		1	N19W04	0000		AXX
Total spot count:		72	160
Sunspot number:		122	260

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 preliminary daily SWPC ap indices. Values in red are based on the official NGDC 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.