The Joint USAF/NOAA Report of Solar and Geophysical Activity, issued on August 16, 2004, provides a comprehensive analysis of solar and geomagnetic conditions observed between August 15 and August 16, 2004. This report, prepared jointly by the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) Space Environment Center and the U.S. Air Force, is part of a series of daily reports that monitor solar activity and its impact on Earth's space environment. These reports are crucial for understanding space weather phenomena and their potential effects on satellite operations, communications, and power systems.

Solar Activity Analysis

During the specified period, solar activity was classified as moderate. The primary focus was on Region 656, located at S13W61 on the solar disk. This region exhibited a beta-gamma-delta magnetic configuration, indicating a complex magnetic field structure prone to flare activity. Notably, Region 656 produced an M1/Sf flare at 03:47 UTC on August 16, 2004. Additionally, a long-duration C9/Sf event occurred at 13:38 UTC, associated with a faint coronal mass ejection (CME) that did not appear to be Earth-directed. Despite these events, Region 656 underwent minimal changes in spot area during the observation period. Another region of interest was Region 661 at N07E34, which remained quiescent but developed a small delta magnetic structure in its southernmost trailing spot. A partial halo CME was observed on the northwest solar limb, though it was not directed toward Earth. The solar activity forecast indicated expectations of moderate to high levels through August 17 and 18, with a gradual decrease anticipated as Region 656 approached the western solar limb on August 19.

Geomagnetic Activity Summary

The geomagnetic field during this period was characterized as quiet to unsettled. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels, suggesting increased energetic particle activity in Earth's magnetosphere. The forecast for geomagnetic activity anticipated quiet to unsettled conditions for the subsequent days, with isolated active conditions possible on August 20 due to the minor effects of a small coronal hole reaching a geoeffective position. The report provided event probabilities for August 17 to 19, including a 75% chance of M-class flares, a 20% chance of X-class flares, and a 10% chance of proton events. The planetary K-index, a measure of geomagnetic activity, indicated values ranging from 3 to 8, corresponding to quiet to active conditions. The forecasted planetary K-index for August 17 to 19 was 8/8, 8/8, and 5/8, respectively, indicating expected active conditions during this period.

Solar and Geophysical Forecasts

The report provided detailed forecasts for solar and geomagnetic activity for the days following August 16, 2004. Solar activity was expected to remain at moderate to high levels, with Region 656 potentially producing major flare activity before it crossed the west limb in the next day. The geomagnetic field was anticipated to be quiet to unsettled for all three days, with isolated active conditions possible on August 20 due to the minor effects of a small coronal hole reaching a geoeffective position. The event probabilities for August 17 to 19 included a 75% chance of M-class flares, a 20% chance of X-class flares, and a 10% chance of proton events. The forecasted planetary K-index values for these days were 8/8, 8/8, and 5/8, respectively, indicating expected active conditions during this period. The report also provided the observed and predicted Penticton 10.7 cm solar flux values, which are used as an indicator of solar activity. The observed value on August 16 was 134, with predicted values of 130, 125, and 115 for August 17, 18, and 19, respectively. The 90-day mean was 108, reflecting the average solar activity over the preceding three months.

Conclusion

The Joint USAF/NOAA Report of Solar and Geophysical Activity for August 16, 2004, offers a detailed assessment of solar and geomagnetic conditions during that period. The report highlights the moderate solar activity, particularly from Region 656, and the quiet to unsettled geomagnetic conditions. The forecasts provided valuable information for anticipating solar and geomagnetic activity in the days following the report, which is essential for space weather prediction and the protection of technological systems sensitive to solar and geomagnetic disturbances. Continuous monitoring and analysis of solar and geophysical activity are vital for understanding space weather dynamics and mitigating potential impacts on Earth-based technologies.

Sources

  • Editor — Joint USAF/NOAA Report of Solar and Geophysical Activity 16 Aug 2004 —
  • Editor — Joint USAF/NOAA Report of Solar and Geophysical Activity 17 Aug 2004 —
  • Editor — Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Aug 2004 —
  • Editor — Joint USAF/NOAA Report of Solar and Geophysical Activity 10 Aug 2004 —
  • Editor — Joint USAF/NOAA Report of Solar and Geophysical Activity 09 Aug 2004 —