Space weather, as far as humans are concerned, is primarily driven by phenomena in the Sun's atmosphere. Solar emmissions have a strong impact on Earth because the Sun is an incomprehensibly huge ball of nuclear hot plasma that, cosmically speaking, idles on the curb right in front of our house. Matter and particles from the Sun (known as solar wind) interact with the Earth's magnetic field and atmosphere. Sometimes these interactions make cool things, like aurora; and sometimes they result in not so cool things, like damaged satellites, GPS problems, and blackouts.
Latest Observations as of 2024-05-12T19:05:00+00:00
-------------------- | R0 | S0 | G0 | |--------------------| | None | None | None | --------------------
Maximums Observed in Last 24 Hours
-------------------- | R3 | S1 | G3 | |--------------------| | Strg | Minr | Strg | --------------------
These are the NOAA Space Weather Scales. They are used to quickly communicate different aspects of space weather conditions and what effects people may experience as a result. Each scale ranges from 1-5, where 1 is minor and 5 is extreme.
This refers to signal blackouts on the lower end of the radio frequency band map, including HF communication and navigational signals. Propagation in these frequencies relies on bouncing radio waves off the ionosphere, and solar flares greatly affect that particular layer of the atmosphere.
Effects range from mild and sporatic signal degradation for weaker flares, to hours of radio blackout on the entire sunlit side of Earth under the strongest.
The sun is always blasting us with radiation. However, during solar eruptions like flares and coronal mass ejections, charged particles may launch toward the Earth at very high velocities. Protons in particular can be accelerated to significant fractions of the speed of light. These high-energy particles are a hazard to the electronics of satellites and the DNA of living beings in orbit around Earth. The radiation can also cause a radio-absorbing layer of electrons to form under the ionosphere, disrupting HF radio communication.
The weakest storms only cause mild HF radio degradation. The most extreme storms result in complete HF radio blackout, damage or destroy satellites, and pose a significant risk to astronauts in space and even to people in high-flying aircraft near the polar regions.
This is the scale most relevant for aurora, but geometric storms can also harm our modern, technological world. The scale is based on the planetary K index, which combines several different measures of disturbances in Earth's magnetic field. Solar wind and the magnetized plasma of coronal mass ejections can exchange energy with Earth's magnetosphere, causing these rapid fluxuations in its shape.
Changes to the global magnetic field create currents that generate heat in the atmosphere, increasing its density and causing extra drag on low-Earth orbit satellites. The heat can also disrupt radio signals and global navigation systems. The power grid and long pipelines may also experience induced currents, leading to electric shock hazards and blackouts.
Aurora is often visible at high latitudes in monor geomagnetic storms. G2-3 storms may cause aurora at 55° or 50° of latitude, and it may be seen as far as 40° in the most extreme cases.
Radio emmissions from the sun on the 10.7cm band are a good proxy indicator for how active the solar atmosphere is in terms of sunspots and flares. It can be measured in all weather conditions, and we have historical records of observations going back decades. Thus, it's reliable for forecasting.
Measurements range from under 50 sfu (solar flux units) for quiet periods to over 300 sfu for very high activity.
Radio Flux 10.7cm - Issued: 2024-05-06
205 +---------------------------------------------------------------------+
| + * +* + + |
200 |-+ * * +-|
| * * |
195 |-+ * * +-|
| * * |
| * * |
190 |-+ * * * +-|
| * * * * |
185 |-+ * * * * +-|
| * * * * |
180 |-+ * * * * +-|
| * * * |
175 |-+ ******* * *** * +-|
| * * * * |
| * * * * |
170 |-+ * * * * +-|
| + + +* * * + * |
165 +---------------------------------------------------------------------+
05/02 05/09 05/16 05/23 05/30 06/06
All data comes from the NOAA Space Weather Prediction Center, which is also an excellent resource for learning more about these topics.