Solar Terrestrial Activity Report

Last major update issued on July 3, 2005 at 05:05 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update July 2, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update July 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update July 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update July 2, 2005)]

Recent activity

The geomagnetic field was quiet to active on July 2. Solar wind speed ranged between 546 and 671 (all day average 572) km/sec under the influence of a high speed stream from CH173.

Solar flux measured at 20h UTC on 2.8 GHz was 123.8. The planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 13.3).
Three hour interval K indices: 43222233 (planetary), 43223334 (Boulder).

The background x-ray flux is at the class B4 level.

At midnight there were 8 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 6 C class events was recorded during the day.

Region 10781 was quiet and stable.
Region 10782 decayed in the trailing spot section.
Region 10783 developed further and is a compact region with M class flare potential.
Region 10784 decayed slowly and quietly.
Region 10785 developed moderately quickly and could produce further C flares. Flares: C3.5 at 03:16, C2.7 at 06:37, C2.0 at 09:29, C2.8 at 12:40 and C1.3 at 19:02 UTC.
Region 10786 is complex with two small magnetic delta structure, one in the northernmost penumbra with the other one located in a penumbra in the southeastern section.  An M class flare is possible. Flare: C1.2 at 16:14 UTC.
Region 10787 decayed slowly and quietly.
New region 10788 rotated into view at the southeast limb on July 1 and was numbered by SEC the following day.

Coronal mass ejections (CMEs)

June 30 - July 2: No obvious fully or partly Earth directed CMEs were observed in available LASCO images.

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 large trans equatorial coronal hole (CH173) was in an Earth facing position on June 28-30.

Processed SOHO/EIT 284 image at 19:06 UTC on July 2. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to active on July 3 and quiet to unsettled on July 4-6.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Rafaela Argentina. Several stations from Argentina were noted on other frequencies with 950 and 1110 kHz having the best signals. From North America both CJYQ on 930 and WWZN on 1510 kHz had poor signals.

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.

Active region Date numbered SEC
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10781 2005.06.27 1 2 N13E10 0050 HSX classification was CSO at midnight
10782 2005.06.29 16 21 S18W32 0220 DAO  
10783 2005.06.29 30 33 S03E20 0500 DKI beta-gamma
classification was DKC at midnight, area 0650
10784 2005.06.29 5 3 N18E30 0040 CSO classification was CAO at midnight, area 0030, location: N16E30
10785 2005.06.30 17 25 S19W06 0070 DSI beta-gamma
classification was DAI at midnight, area 0100
10786 2005.07.01 11 22 N12E62 0370 DAO beta-gamma-delta
classification was DKI at midnight
10787 2005.07.01 7 9 S11W34 0030 DSO location: S09W34
10788 2005.07.02 1 2 S06E70 0120 HAX formerly region S566
area was 0090 at midnight, location: S05E68
S563 2005.06.27     N10W30     plage
Total spot count: 88 117  
SSN: 168 197  

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2004.05 99.8 41.5 43.8 (-1.7)
2004.06 97.4 43.2 41.6 (-2.2)
2004.07 119.1 51.1 40.2 (-1.4)
2004.08 109.6 40.9 39.2 (-1.0)
2004.09 103.1 27.7 37.5 (-1.7)
2004.10 105.9 48.0 35.9 (-1.6)
2004.11 113.2 43.5 35.3 (-0.6)
2004.12 94.5 17.9 35.2 (-0.1)
2005.01 102.2 31.3 (34.6 predicted, -0.6)
2005.02 97.2 29.1 (33.3 predicted, -1.3)
2005.03 89.9 24.8 (31.6 predicted, -1.7)
2005.04 86.0 24.4 (29.7 predicted, -1.9)
2005.05 99.3 42.6 (27.2 predicted, -2.5)
2005.06 93.7 39.3 (25.7 predicted, -1.5)
2005.07 119.2 (1) 9.4 (2) (24.7 predicted, -1.0)

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% lower.

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


[DX-Listeners' Club]