The Joint USAF/NOAA Solar Geophysical Activity Report and Forecast, issued on December 9, 2019, provided a comprehensive analysis of solar and geomagnetic conditions observed from December 8 to December 9, 2019, along with forecasts for the subsequent three days. This report is part of a series of daily bulletins produced collaboratively by the United States Air Force (USAF) and the National Oceanic and Atmospheric Administration (NOAA), aimed at monitoring and forecasting solar and geophysical activity. Such reports are crucial for understanding space weather phenomena and their potential impacts on Earth-based technologies and infrastructure.
Solar Activity Analysis
During the 24-hour period from 2100 UTC on December 8 to 2100 UTC on December 9, 2019, solar activity was classified as very low. Notably, there were no numbered sunspot regions observed on the Sun's disk, indicating minimal solar activity. This assessment aligns with the solar activity forecast, which anticipated very low levels for December 10, 11, and 12, 2019. Such periods of low solar activity are characterized by a lack of significant solar flares or coronal mass ejections (CMEs), phenomena that can influence space weather conditions on Earth.
Geomagnetic Activity Summary
The geomagnetic field during the same 24-hour period exhibited quiet to unsettled levels. The solar wind speed peaked at 384 km/s at 2208 UTC on December 8, 2019. Additionally, electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 137 pfu (particles per flux unit). These measurements are essential for assessing the potential impact of solar wind and energetic particles on Earth's magnetosphere, which can affect satellite operations, communication systems, and power grids.
Forecast of Geophysical Activity
The forecast for the subsequent three days (December 10, 11, and 12, 2019) projected that the geomagnetic field would remain at quiet levels. This prediction suggests that space weather conditions were expected to remain stable, with minimal disturbances to Earth's magnetosphere. Such forecasts are vital for preparing and mitigating potential impacts on technological systems sensitive to space weather variations.
Event Probabilities and Indices
The report provided specific probabilities for various solar and geophysical events over the forecast period:
- Class M Solar Flare Probability: 1% for each day (December 10, 11, and 12, 2019).
- Class X Solar Flare Probability: 1% for each day.
- Proton Event Probability: 1% for each day.
- Penticton 10.7 cm Flux: Observed at 071 on December 9, 2019, with a forecast of 070 for each of the following three days. The 90-day mean was 069.
- Geomagnetic A Indices: Observed Afr/Ap indices were 002/002 on December 8, 2019, with estimated values of 008/008 on December 9, 2019. Predicted values for December 10 to 12, 2019, were 006/005, 006/005, and 006/005, respectively.
These indices and probabilities are standard metrics used in space weather forecasting to assess the likelihood of solar flares, proton events, and geomagnetic storms, which can have various effects on Earth-based technologies and infrastructure.
Context and Importance of the Report
The Joint USAF/NOAA Solar Geophysical Activity Report and Forecast is part of a daily series of bulletins issued by the NOAA Space Weather Prediction Center (SWPC) and the USAF 557th Weather Wing. These reports provide summaries and analyses of solar and geomagnetic activity, offering forecasts for the next three days. The information is crucial for understanding space weather phenomena and their potential impacts on Earth-based technologies and infrastructure. The reports are accessible through the NOAA SWPC website, which serves as a resource for current and historical space weather data and forecasts.
Understanding solar and geomagnetic activity is essential for various sectors, including satellite communications, navigation systems, power grids, and aviation. For instance, increased solar activity can lead to radio communication disruptions, GPS signal degradation, and even power grid failures. Therefore, accurate and timely forecasts, such as those provided in the Joint USAF/NOAA reports, are vital for mitigating the effects of space weather on technological systems and ensuring the safety and reliability of critical infrastructure.
In summary, the Joint USAF/NOAA Solar Geophysical Activity Report and Forecast for December 9, 2019, indicated a period of very low solar activity and quiet geomagnetic conditions, with forecasts suggesting continued stability. Such reports are integral to space weather monitoring and forecasting, providing essential information for understanding and mitigating the impacts of solar and geomagnetic events on Earth-based technologies and infrastructure.
Sources
- Editor — Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 9 December 2019 —
- NOAA Space Weather Prediction Center — Report and Forecast of Solar and Geophysical Activity —