The space around the Earth (geospace), including the upper atmosphere, is highly dynamic. This is due to ultraviolet and X-ray radiation from the Sun, magnetic storms caused by high-energy plasma particles from solar explosions, and atmospheric waves from the lower atmosphere. These geospace variations affect radio communications between satellites and the ground, causing satellite positioning and communication failures. Magnetic storms also cause the atmosphere to heat and expand resulting in alteration of satellites’ orbits. In addition, high-energy plasma particles from solar explosions and magnetic storms cause radiation hazards to astronauts, satellites, and aircraft crews. As humanity’s use of space continues to increase, understanding and predicting these geospace variabilities have become an urgent issue.

To understand the mechanism behind geospace variability, it is necessary to combine ground instruments and satellites. This allows for comprehensive measurements of geospace. Furthermore, there is also a need to coordinate with modeling through numerical simulations to complement sparse observations and for quantitative evaluations, including space weather prediction. The PBASE program aims to significantly contribute to understanding and predicting geospace variabilities by combining ground-based and satellite observations and modeling, covering a wide area in both altitude and latitude/longitude directions.

Early-career researchers including newly hired Post-Doctoral Fellows and Ph.D students are participating in this program. All these students and early career scientists will be promoting research focusing on ground-based observation and modeling. They will stay overseas Co-I’s institutes to compare their own ground observations and modeling, with satellite observations/modeling. This experience will let them develop broad research skills to approach scientific topics using different methods. We also support their field trips for their experience of ground-based measurements. We also invite overseas students and early-career scientists to stay in Japan for 3 months for collaborative research.

Oversea Stays and Trips

Oversea and domestic field trips

This program was adopted in December 2022 and is planned for seven years from FY2022 to FY2028. The EISCAT_3D radar will start operation in the first half of 2023. Intensive campaign observations will be conducted in the winter of the second and third years when the radar starts operating, and in the winter of 2025 when the solar activity is expected to reach a maximum. A group of satellites has already been launched and is still in operation. In the event of failure of these satellites, the results will be achieved through the use of observation data and collaboration with other satellites. The global model will be pre-tuned over the next year, and then validated and refined through comparison with observations to reproduce and quantify global geospatial variability. We will continue to build a common ground-satellite-modelling database and develop tools for integrated analysis of all data.