Space exploration and space utilization have spread rapidly. Consequently, solar activity is now known to significantly impact the global environment as well as human socio-economic systems; however, the mechanisms for solar eruptions and the subsequent processes have not yet been fully explained. Therefore, modern society, which is supported by advanced information systems, is at a risk from severe space weather disturbances.
However, solar activity, which corresponds to the sunspot number, shows an 11/22-year cycle, and the current solar activity (Cycle 24) is considered to be the least in the last few decades. Therefore, there is a possibility that solar activity may be shifting back into a quiet phase such as that seen in the Maunder Minimum, during which the sunspot number was significantly smaller and the terrestrial climate fell to the so-called Little Ice Age. However, the physical processes by which solar activity affects terrestrial climate variations are not very clear; therefore, solar influence is one of the sources of uncertainty in climate change projections.
This project aims to develop a synergistic interaction between predictive and scientific studies of the solar-terrestrial environmental variation to establish the basis for next-generation space weather forecasting using state-of-the-art observation systems and advanced physics-based models. By this project, we seek to answer some of the fundamental questions concerning the solar-terrestrial environmental system such as the mechanisms for the onset of solar flares, the mechanism for radiation belt dynamics in the Earth’s magnetosphere, and the physical process by which solar activity affects the climate. Moreover, we aim to contribute to building a next-generation space weather forecast system to prepare for severe space weather disasters that will occur in future.
For this project, we coordinate the research groups and proposal-based research units. The research groups are organized by a nation-wide collaboration of multiple institutes for each particular subject (Subject 1–4). The research units are led by individual researchers and they cooperate with the related research groups. The subjects for the research groups and units are as follows:
Subject 1) The development of a next-generation space weather forecast system: (Group A01, leader: Mamoru Ishii, NICT)
To develop a novel space weather forecast system to prepare for severe space weather disasters and to improve the scientific understanding by evaluating the predictions.
Subject 2) The prediction of solar storms: (Group A02, leader: Kiyoshi Ichimoto, Kyoto University)
To establish a system to predict solar eruptions using state-of-the-art observation systems and advanced physics-based models for solar eruption and interplanetary coronal mass ejections.
Subject 3) The prediction of magnetosphere and ionosphere dynamics: (Group A03, leader: Yoshizumi Miyoshi, Nagoya University)
To establish a system to predict disturbances of space radiation, ionospheric storms, and geomagnetically induced currents.
Subject 4) The prediction and understanding of solar cycle activity and its impact on climate: (Group A04, leader Shigeo Yoden, Kyoto University)
To understand the cause of the solar cycle and its impact on climate, for which the prediction of the next solar cycle (Cycle 25) will be attempted.
Subject 5) Mathematical sciences for solar-terrestrial environment prediction:
To develop various types of mathematical and numerical studies for predicting solar-terrestrial environmental variability, e.g., the development of new algorithms, high-performance computing, machine learning prediction, assimilation techniques, and big data mining for prediction. The proposal-based research units are investigating this subject.