What is Space Weather Forecasting?: Solar Activity and Its Impact on Earth.

This time, I would like to talk about "space weather forecasting," which is deeply involved in our daily lives but not very well known. When you hear "weather forecast," you might think of tomorrow's rain or temperature, but space weather forecasting is on a much grander scale, predicting phenomena caused by solar activity on Earth. What kind of forecast is it exactly? And why is it important to us?

What is space weather forecasting? Why is it getting attention now?

"Space weather forecasting" refers to providing information to predict various phenomena caused on a global scale by changes in solar activity and to protect our lives from their effects. It is known that solar activity affects the Earth's magnetic field, ionosphere, and even the weather.
In recent years, our society has become heavily dependent on technologies that use outer space and radio waves, such as smartphones, GPS, the internet, and power grids. What would happen if large-scale failures occurred in these infrastructures due to solar activity? Space weather forecasting is essential for detecting such risks in advance and minimizing damage.

What is solar activity? Approaching its true nature!

So, what exactly is "solar activity"? The sun is a massive star that is constantly emitting vast amounts of energy. Solar activity refers to various phenomena caused by changes in the magnetic field generated inside the sun, and this activity triggers various phenomena that we call "solar activity."
Representative solar activities include solar flares, coronal mass ejections (CMEs), and solar wind.
First, a solar flare refers to a large-scale explosion that occurs suddenly on the sun's surface. Due to this explosion, powerful electromagnetic waves of various wavelengths, such as X-rays, ultraviolet rays, and radio waves, are emitted into space all at once. These electromagnetic waves reach Earth at the speed of light and affect the Earth's ionosphere.
Next, a coronal mass ejection (CME) is a phenomenon in which a huge mass of plasma is ejected into space from the corona, the outermost layer of the sun. When this mass of plasma reaches Earth, it interacts with the Earth's magnetic field and can cause global disturbances called geomagnetic storms. The speed of a CME is faster than the solar wind, and it takes several days to reach Earth. By the way, the "corona" in coronal mass ejection (CME) iscoronathe outermost atmospheric layer of the sun. It is usually hidden by the sun's dazzling light and cannot be seen, but it is what looks like a white glowing veil around the sun during a total solar eclipse.
Furthermore, solar wind refers to the constant stream of charged particles (plasma) blowing from the sun, which is called "solar wind." The solar wind interacts with the Earth's magnetic field to cause beautiful auroras, but at the same time, it can also affect the operation of artificial satellites orbiting the Earth.
When these solar activities become active, the Earth's magnetic field and ionosphere are greatly disturbed, and they begin to have concrete effects on our lives.

Concrete effects of space weather on Earth: A direct hit to our lives!

So, what kind of impact does it have on our lives when solar activity becomes active? Let's look at some concrete examples.
The first is communication failure. X-rays and ultraviolet rays emitted by solar flares affect the Earth's ionosphere, which can cause failures in radio usage such as shortwave communication and GPS. If GPS becomes unusable in modern society, it could cause confusion in a wide range of fields, including logistics, aviation, and location information services.
The second is artificial satellite failure. High-energy particles emitted by coronal mass ejections (CMEs) are a serious threat to artificial satellites orbiting the Earth. If these particles collide with the satellite's electronic equipment, the equipment may deteriorate or malfunction. In the worst case, expensive artificial satellites may be forced to stop operating, affecting various services such as weather observation, communication, and broadcasting.
The third is the impact on power grids. When a geomagnetic storm occurs, the Earth's magnetic field fluctuates significantly, and as a result, induced currents are generated in the ground. If this induced current flows into the power grid, it can put excessive load on transformers and cause large-scale power outages. In the past, cases of large-scale power outages have actually been reported, and it can be said that the risk to social infrastructure is very high.
The fourth is the impact on aircraft operations. Aircraft flying in high-latitude regions, especially polar regions, are at risk of increased radiation exposure for crew and passengers due to solar flares. For this reason, flight routes are sometimes changed or flights are suspended based on space weather forecasts.
The fifth is the occurrence of auroras. As the solar wind interacts with the Earth's magnetic field, auroras, which are usually only seen in high-latitude regions, occur. When solar activity is very active, they can sometimes be observed in low-latitude regions where auroras are not usually seen. This is a relatively "beautiful" phenomenon among the effects, but we must not forget that large-scale geomagnetic fluctuations are hidden behind it.
The sixth is the impact on climate change; it has also been pointed out that changes in solar activity may affect the Earth's climate in the long term. However, there are still many unknown points about the mechanism, and it is a field where research is currently underway.

Utilization of space weather forecasting: To prevent risks in advance

Considering these potential risks, you can understand how important space weather forecasting is. In fact, space weather forecasting is used in various fields to predict the effects of these solar activities and minimize damage.
In the operation of artificial satellites, based on space weather forecasts, it is possible to control the attitude of the satellites and take measures to protect electronic equipment. This extends the life of the satellites and maintains stable service provision.
In the operation of power systems, based on the prediction of geomagnetic storms, it is possible to adjust the load on the power grid and prepare to activate protective devices such as transformers. This reduces the risk of large-scale power outages.
Regarding aircraft operations, safety measures such as changing flight routes and monitoring the radiation exposure of crew and passengers are taken based on the prediction of solar flares.
And communication carriers can strengthen the backup system of communication systems and alert users based on the prediction of communication failures.

Current status and future challenges of space weather forecasting

Currently, research on space weather forecasting is being actively conducted around the world, and in Japan, the National Institute of Information and Communications Technology (NICT) provides space weather forecasts.
However, predicting solar activity remains a very difficult challenge. In particular, it is required to further improve the accuracy of predicting the arrival time of coronal mass ejections (CMEs) to Earth and their scale.
Also, it is an important challenge to provide space weather forecast information in a form that is easy for the general public, not just experts, to understand. Since the effects of solar activity are deeply involved in our lives, it is very important that more people become interested in space weather and become able to take appropriate measures when the time comes.

The "Carrington Event" that made the importance of space weather forecasting known

Here, I would like to introduce a famous event that historically supports the importance of space weather forecasting. That is the "Carrington Event" that occurred in 1859. This is considered one of the most powerful solar storms on record and was a major trigger for us to recognize the need for space weather forecasting.
At this time, one of the largest solar flares and coronal mass ejections in recorded history occurred on the sun, and it reached Earth a few days later. As a result, accidents were reported where telegraph lines actually caught fire and telegraph operators received electric shocks.
Even more surprising is that the aurora, which is usually only seen in high-latitude regions, was powerful enough to be observed in regions near the equator. If a solar storm of the same scale were to occur in modern society, it is said that it could cause enormous damage to power grids and communication infrastructure. The Carrington Event is sounding an alarm to us not just as a past event, but as a risk that modern society could face.

Summary: Our future protected by space weather forecasting

Space weather forecasting is very important information for predicting global phenomena caused by changes in solar activity and reducing the impact on our society and lives.
By grasping various risks such as communication failures, artificial satellite failures, and large-scale impacts on power grids in advance and taking appropriate measures, we can ensure the safety and security of society.
We look forward to further improvements in the accuracy of space weather forecasting and the enrichment of information provided to the general public. By each of us taking an interest in space weather, we will be able to build a safer and more resilient society.
Thank you for watching until the end! I hope this video helps you deepen your understanding of space weather forecasting. See you next time!

※This article is based on what was posted on YouTube.