Solar Terrestrial Activity Report

Last major update issued on July 1, 2006 at 03:55 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update June 7, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 7, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 7, 2006)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update June 5, 2006)]

Recent activity

The geomagnetic field was quiet to unsettled on June 30. Solar wind speed ranged between 458 and 567 km/s (all day average 503 km/s - decreasing 54 km/s from the previous day) as the high speed stream from CH229 weakened.

Solar flux measured at 20h UTC on 2.8 GHz was 86.1. The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.3).
Three hour interval K indices: 22223112 (planetary), 23333321 (Boulder).

The background x-ray flux is at the class A8 level.

At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.

Region 10897 decayed slowly and quietly.
Region 10898 decayed losing several spots. Polarities are still poorly separated and there is a chance of C flares.

Spotted regions not numbered by NOAA/SEC:
[S666] This region decayed slowly on June 30. Location at midnight: N05W04

Coronal mass ejections (CMEs)

June 28-30: No partly or fully Earth directed CMEs were detected in LASCO imagery.

Coronal holes

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

A recurrent trans equatorial coronal hole (CH230) will likely rotate into an Earth facing location on July 2-3.

Processed SOHO/EIT 284 image at 13:06 UTC on June 30. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be mostly quiet on July 1-3 and become unsettled to minor storm from late on July 4 until July 6.

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) 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.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Radio Cristal del Uruguay had a strong signal most of the time, however, Radio Vibración (Venezuela) was occasionally on the top. 1390 kHz had many stations coming and going with Radio Universidad (Argentina), Radio Fé y Alegria (Venezuela) and Rádio Cultura Maringá (Brazil) all on top at times. With local NRK Kvitsoy on 1314 kHz off (final day of transmission was June 30) several stations, mostly from Brazil, were noted on previously blocked frequencies 1310 and 1320 kHz.

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
10897 2006.06.25 10 8 N07E02 0040 DRO classification was DSO at midnight
location: N07E04
10898 2006.06.28 8 8 S06E40 0350 DSO beta-delta
classification was DKO at midnight
S666 2006.06.28   1 N05W04 0020 HSX split off from 10897
Total spot count: 18 17  
SSN: 38 47  

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)
2005.04 86.0 24.2 31.6 (-1.9)
2005.05 99.3 42.7 28.9 (-2.7)
2005.06 93.7 39.3 28.8 (-0.1)
2005.07 96.4 40.1 29.1 (+0.3)
2005.08 90.5 36.4 27.4 (-1.7)
2005.09 91.1 21.9 25.8 (-1.6)
2005.10 77.0 8.5 25.5 (-0.3)
2005.11 86.3 18.0 24.9 (-0.6)
2005.12 90.7 41.2 (22.8 predicted, -2.1)
2006.01 83.4 15.4 (20.1 predicted, -2.7)
2006.02 76.5 4.7 (17.1 predicted, -3.0)
2006.03 75.4 10.8 (15.1 predicted, -2.0)
2006.04 89.0 30.2 (14.4 predicted, -0.7)
2006.05 80.9 22.2 (13.5 predicted, -0.9)
2006.06 76.5 (1) 24.4 (2) (11.4 predicted, -2.1)

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]