When we think of weather, we usually think of wind, precipitation, temperature and sunshine. However, some astronomy enthusiasts also focus on the solar cycle and its global repercussions. In the drone business, as in aviation, understanding the basics of solar weather is crucial to safe flight operations. This article aims to make this little-known reality accessible and understandable to a wide audience.
What is solar weather?
Solar weather refers to the study of phenomena generated by solar activity and their impact on our space environment. The Sun, a dynamic star, follows an activity cycle of around 11 years, divided into periods of high activity, called “solar maximum”, and periods of low activity, called “solar minimum”.
The phases of the solar cycle
- Solar minimum: Period when the Sun is least active, with few or no sunspots and low solar flare and coronal mass ejection (CME) activity.
- Solar maximum: Period of high activity, marked by an increase in sunspots, frequent solar flares and an increased risk of geomagnetic storms on Earth.
Although the mechanisms behind this cycle remain partially understood, it has been observed for several centuries. Initially through the study of sunspots, then through modern solar telescopes and specialized satellites that constantly scrutinize solar activity.
Over the years, our understanding of solar events has deepened, enabling us to better anticipate their effects on the Earth. Among the most important solar events, two in particular stand out for their ability to disrupt our planet’s natural magnetic field: solar winds and solar storms.
Definition and comparison of a solar storm and a solar flare.
Solar winds
The Sun emits a continuous stream of charged particles, known as the solar wind. This wind comes from the Sun in the form of plasma, a material composed of electrons and atomic nuclei, and moves through space in an oscillating spiral. This phenomenon is influenced by the Sun’s rotation, creating a dynamic in which the faster the solar wind, the greater its impact on the Earth’s magnetic field. These interactions can affect the stability of satellite systems, disrupt communications networks and cause interference with GPS systems.
Solar storms
Like terrestrial storms, the Sun also experiences “storms”, but these are primarily magnetic, rather than meteorological. A solar storm occurs when the Sun’s magnetic fields abruptly reposition, ejecting particles and radiation into space. It’s a sudden phenomenon that can give rise to other phenomena.
- Solar flare – When the Sun emits large quantities of radio waves, gamma rays and light, it is called a solar flare. The consequences of a solar flare on Earth are relatively limited, affecting only the quality of radio signals, particularly at the poles. A very strong solar flare, however, can cause radio “blackouts” anywhere in the world.
- Radiation storm – A rarer phenomenon that sometimes accompanies a solar flare, a radiation storm, although not harmful to living beings on Earth, can still affect the health of astronauts and high-altitude crews, and damage or even destroy satellites, as well as further degrading radio communications.
- Coronal mass ejection (CME) – A CME is an intense release of magnetized plasma, which propagates through space and can interact with the Earth’s atmosphere. When such a wave of plasma hits our planet, it can trigger a series of events, ranging from minor or major interference with GPS signals to spectacular phenomena such as the Northern Lights.
The northern lights
One of the most fascinating consequences of solar weather is the aurora borealis, a spectacular luminous phenomenon visible mainly in regions close to the Arctic Circle. These dancing, colorful lights that illuminate the night sky are the direct result of interactions between charged solar particles and the Earth’s magnetic field, the Earth’s protective layer against solar phenomena. When the Sun emits electrically charged particles, such as protons and electrons, these can be captured by the Earth’s magnetosphere. Once these particles enter the Earth’s atmosphere, they collide with oxygen and nitrogen molecules, producing visible light in the form of auroras, mainly in shades of green, violet and red.
On May 10, 2024, a large part of the northern hemisphere, including Quebec, had the chance to observe this unique phenomenon, including in urban areas where, despite light pollution, some fantastic aurora borealis could be seen. This type of event, although extraordinary in regions far from the poles, is an illustration of the impact of solar weather on our planet, particularly during periods of high solar maximum. During these periods, solar activity is at its peak, increasing the chances of spectacular auroras.
However, forecasting this luminous phenomenon remains a challenge. The only reliable method of anticipating the aurora is to closely monitor solar weather on a regular basis, particularly during periods of high solar activity. By monitoring solar flares and coronal mass ejections, it is possible to determine when conditions will be favorable for the appearance of auroras.
It’s important to note that when the aurora borealis appear, it’s not advisable to fly a drone, due to the potential magnetic disturbances that can affect navigation systems. To immortalize this spectacular phenomenon, using a ground camera remains the best option, allowing you to capture the beauty of the aurora in all its splendor without risk to aerial equipment.
Milestones: Carrington Even in 1859, the 1989 blackout, etc.
The Sun, an indispensable source of life on Earth, also has the power to generate serious disturbances that can affect our technology and infrastructure. One of the most significant and studied events in the history of solar interaction with the Earth is the Carrington Event of 1859. This phenomenon was triggered by a massive solar flare accompanied by a coronal mass ejection (CME) that struck the Earth with extraordinary intensity. The effects were so powerful that the Earth’s magnetic field was significantly disrupted, inducing electric currents in telegraph lines. In some stations, these induced currents were strong enough to cause spontaneous fires. This event is often cited as the greatest example of the impact of a solar storm on the technological systems of the time.
More recently, in March 1989, the Earth was hit by another major solar storm. This time, the effects were particularly marked in the Canadian Shield region, where the geological properties of the soil exacerbated the impact. The storm caused a massive blackout across the entire Hydro-Québec network, depriving millions of homes of power for almost nine hours. The blackout highlighted the vulnerability of modern infrastructures to solar phenomena, and served as a starting point for a better understanding of the risks associated with solar weather.
While it’s difficult to predict precisely when such an event will occur again, it’s almost certain that we’ll face similar incidents again in the future. Scientists believe that solar storms can occur at any time, and in the best-case scenario, we could have only a few days’ notice before a coronal mass ejection hits the Earth. However, it’s important to note that mitigation measures have been put in place since the 1989 blackout to minimize the impact of future solar storms. Investments in protecting power grids, improving solar forecasting and implementing safety protocols for satellites and communications systems have been priorities for governments and businesses alike.
Overall, although these events are rare, their potential for disruption is high enough to warrant continued vigilance. Monitoring solar activity and preparing infrastructures are now strategic priorities for limiting the impact of solar storms on modern society.
Impact on GNSS/GPS systems and drones
Solar activity has a direct influence on flying conditions, particularly during solar maximum, which currently corresponds to the years 2024-2025. Although these disturbances are not visible to the naked eye, they can have a major impact on aeronautical navigation and communication technologies.
In the aviation sector, the effects of solar weather are well documented and manifest themselves mainly in three forms:
- Damage to radio communications: solar storms can cause interference on radio frequencies used for communication between pilots and control towers, or between the operator’s radio control system and the drone.
- Increased exposure to solar radiation: At high altitudes, pilots and crew are more exposed to the energetic particles emitted during solar storms.
- GNSS/GPS systems disruption: satellite signal accuracy may be altered, directly impacting aircraft and UAV navigation.
Increased risk for drones and autonomous aviation
GNSS/GPS systems play a key role in stabilizing and navigating aircraft, especially drones. Manufacturers like DJI have widely integrated this technology to ensure optimum accuracy and reliability. However, during a geomagnetic storm, GPS signal reliability can be severely compromised, resulting in :
- Positioning errors (drift),
- Loss of GPS signal,
- Crash risk in the event of prolonged GNSS signal interruption.
Monitoring the KP index to secure flights
One of the key indicators for assessing the risk of GPS disruption is the Kp index, which measures the intensity of geomagnetic storms on a scale of 0 to 9 :
- Kp index between 4 and 5: Risk of GNSS/GPS signal interference, caution recommended.
- Kp index ≥/= 5: Major disturbances possible, we strongly advise against flying a drone.
Before any flight, it is therefore essential to consult the geomagnetic forecasts available on specialized platforms to avoid any critical interference that could compromise the safety of flight operations.
Conclusion
To ensure safe and compliant operations, drone operators need to integrate solar weather into their pre-flight analyses. A good understanding of solar phenomena and their impact on GNSS/GPS systems is essential to avoid any disturbances that could compromise aircraft stability and reliability.
Fortunately, tracking solar activity and anticipating its effects on flying conditions is a simple and accessible process. Specialized platforms such as Space Weather Liveprovide real-time data on the Kp index and solar storms, enabling pilots to make informed decisions and adjust their flight plans accordingly.
By staying informed and adopting good safety practices, any operator can minimize the risks associated with geomagnetic storms and guarantee safe, reliable flights, even during periods of high solar activity.
Frequently asked questions – FAQ
When was the last severe storm or geomagnetic storm?
Geomagnetic storms occur regularly, but some are more powerful than others. One of the most recent major storms occurred in May 2024, reaching a G5 level, the highest degree of intensity on the NOAA scale. This exceptional event resulted in the aurora borealis being visible at unusual latitudes, including parts of the USA and Europe, as well as disruptions to communications and navigation systems.
Before that, another landmark event occurred in March 1989, when an extreme solar storm caused a widespread blackout in Hydro-Québec’s power grid, leaving millions of people without electricity for several hours.
When will the next solar storm occur in 2025?
Predicting the exact date of a solar storm is a challenge, but scientists know that solar activity follows a cycle of around 11 years, so the next solar maximum is scheduled for 2025, which means we could see an increase in solar flares, coronal mass ejections (CMEs) and, potentially, intense geomagnetic storms.
Space agencies such as NOAA and NASA constantly monitor the Sun’s activity via dedicated satellites. When a flare or CME occurs, the Earth generally has 24 to 48 hours before the charged particles reach our planet. This makes it possible to anticipate the impact on power grids, satellites and radio communications.
How do you see a solar storm?
It’s impossible to see a solar storm directly with the naked eye, but its effects can be spectacular, especially in the form of aurora borealis and aurora australis. Here are a few ways to observe them:
- Monitor space weather forecasts: Sites like the Space Weather Prediction Center (NOAA) and the European Space Agency provide real-time forecasts of solar storms and their potential impact on Earth.
- Observing the aurora borealis: During a solar storm, charged particles interact with the Earth’s atmosphere, creating auroras visible mainly near the poles. During particularly intense events, they can be seen further south, in unusual regions. Specialized websites and applications allow you to follow their forecast in real time.
- Using specialized instruments: Solar telescopes allow you to observe solar flares and sunspots in complete safety. Some satellites, such as the Solar and Heliospheric Observatory (SOHO), also publish images of the Sun in real time, accessible to the general public.
In short, although we can’t see a solar storm directly, its effects on our planet, including the aurora borealis and electromagnetic disturbances, are fascinating manifestations of the Sun’s activity. With solar maximum expected in 2025, it will be particularly interesting to follow these phenomena in the months to come.