Solar Terrestrial Activity Report

Last major update issued on January 15, 2004 at 04:30 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update January 4, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update January 4, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update January 4, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update October 15, 2003)]
[Archived reports (last update January 9, 2004)]

Recent activity

The geomagnetic field was quiet to unsettled on January 14. Solar wind speed ranged between 454 and 596 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 121.1. The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.6).
Three hour interval K indices: 33233322 (planetary), 33133222 (Boulder).

The background x-ray flux is at the class B3 level.

At midnight there were 4 spotted regions on the visible disk. Solar flare activity was low. A total of 1 C class event was recorded during the day, a C1.0 flare at 16:02 UTC in region 10536 at the southwest limb.

Region 10537 decayed further losing penumbral area. Some new small spots emerged in the south during the latter half of the day. The positive polarity umbra within the predominantly negative polarity large penumbra is fading and could soon disappear. A minor M flare remains a possibility.
Region 10540 was mostly unchanged and quiet.

Spotted regions not numbered by NOAA/SEC:
[S330] This region emerged early on January 13 in the southeast quadrant, then lost all spots before gaining new spots late that day. Slow development was observed on January 14. Location at midnight: S08E09.
[S332] A new region began rotating into view at the northeast limb late on January 14. Location at midnight: N11E80.

There is an unusually large and dense tilted J-shaped filament in the northeast quadrant, it is trailing coronal hole CH76 and has nearly the same shape. An eruption of this filament will cause a large CME.

Coronal mass ejections (CMEs)

January 13-14: No partly or fully earth directed CMEs observed.

January 12: A CME was observed over the northwest limb, the north pole and part of the northeast limb late in the day. This slow CME was probably associated with an erupting filament in the northwest quadrant.

Coronal holes

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

A recurrent trans equatorial coronal hole (CH76) will rotate into a geoeffective position on January 13-16, the coronal hole is well defined in the northern and central parts.

Processed SOHO/EIT 284 image at 01:06 UTC on January 15. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 15 with unsettled to minor storm conditions possible from noon on January 16 until January 19 because of a high speed stream from coronal hole CH76.

Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor and improving. Propagation along long distance north-south paths is good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and several stations from Brazil on the southwesterly antenna. Excellent, near local like signals were heard at times from Rádio Clube Paranaense on 1430 kHz and Rádio Bandeirantes on 1360 kHz. After 03:30 UTC propagation began to favor stations further north with Radio Vibración coming in well on 1470 kHz and quite a few North American stations becoming audible].

Coronal holes (1)	Coronal mass ejections (2)	M and X class flares (3)

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) Material from a CME is likely to impact 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 (Recent map)

Compare to the previous day's image.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. 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 SEC or where SEC has observed no spots. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.

Monthly solar cycle data

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.

This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.