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Ishii, Mamoru*; Shiota, Daiko*; Tao, Chihiro*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Ishii, Takako*; Ichimoto, Kiyoshi*; Kataoka, Ryuho*; Koga, Kiyokazu*; Kubo, Yuki*; et al.
Earth, Planets and Space (Internet), 73(1), p.108_1 - 108_20, 2021/12
Times Cited Count：8 Percentile：57.39(Geosciences, Multidisciplinary)We surveyed the relationship between the scale of space weather events and their occurrence rate in Japan and we discussed the social impact of these phenomena during the Project for Solar-Terrestrial Environment Prediction (PSTEP). The information was compiled for domestic users of space weather forecasts for appropriate preparedness against space weather disasters. This paper gives a comprehensive summary of the survey, focusing on the fields of electricity, satellite operations, communication and broadcasting, satellite positioning usage, aviation, human space activity, and daily life on the Earth's surface, using the cutting-edge knowledge of space weather. Quantitative estimations of the economic impact of space weather events on electricity and aviation are also given.
Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：51.19(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Miyoshi, Yoshizumi*; Ueno, Haruka*; Nagamatsu, Aiko*
Journal of Space Weather and Space Climate (Internet), 9, p.A9_1 - A9_11, 2019/03
Times Cited Count：7 Percentile：38.79(Astronomy & Astrophysics)Real-time estimation of astronaut doses during solar particle events (SPE) is one of the most challenging tasks in cosmic-ray dosimetry. We therefore develop a new computational method that can nowcast the solar energetic particle (SEP) as well as galactic cosmic-ray (GCR) fluxes on any Earth orbit during a large SPE associating with ground level enhancement. It is an extended version of WArning System for AVIation Exposure to Solar Energetic Particle, WASAVIES. The extended version, called WASAVIES-EO, can calculate the GCR and SEP fluxes outside a satellite based on its two-line element data. Moreover, organ dose and dose-equivalent rates of astronauts in the International Space Station (ISS) can be estimated using the system, considering its shielding effect. The accuracy of WASAVIES-EO was validated based on the dose rates measured in ISS, as well as based on high-energy proton fluxes observed by POES satellites.
Kataoka, Ryuho*; Sato, Tatsuhiko; Miyake, Shoko*; Shiota, Daiko*; Kubo, Yuki*
Space Weather, 16(7), p.917 - 923, 2018/07
Times Cited Count：19 Percentile：69.84(Astronomy & Astrophysics)A ground level enhancement (GLE) event occurred on 10-11 September 2017, associated with X8.2 solar flare exploded at western limb. The magnitude of the GLE was not so large even at the peak, but the duration of the event was longer than average. We briefly report the results of our manually conducted nowcast using WASAVIES (Warning System of AViation Exposure to Solar energetic particles). The maximum radiation dose rate at 12 km flight altitude was estimated to be approximately 2 
Sv/h, which is only one-third of the corresponding background dose rate due to the galactic cosmic-ray exposure. This result verified the safety of aircrews and passengers in aviation during this event.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*
Space Weather, 16(7), p.924 - 936, 2018/07
Times Cited Count：19 Percentile：69.84(Astronomy & Astrophysics)A physics-based warning system of aviation exposure to solar energetic particles, WASAVIES, is improved to be capable of real-time and automatic analysis. In the improved system, the count rates of several neutron monitors (NM) at the ground level, as well as the proton fluxes measured by the GOES satellite are continuously downloaded at intervals of 5 min and used for determining the model parameters. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.
Kubo, Yuki*; Kataoka, Ryuho*; Sato, Tatsuhiko
Earth, Planets and Space (Internet), 67(1), p.117_1 - 117_13, 2015/12
Times Cited Count：13 Percentile：39.29(Geosciences, Multidisciplinary)One of the extreme space weather phenomena are solar energetic particles (SEPs). The huge SEP event causes a radiation dose enhancement to aircrews to be warned as soon as possible. To warn a radiation dose enhancement to aircrew, we have tried to develop warning system for radiation exposure to solar energetic particles. This article describes one component of the system, which calculates temporal evolution of SEP intensity and spectrum just outside the terrestrial magnetosphere.
Sato, Tatsuhiko; Kataoka, Ryuho*; Yasuda, Hiroshi*; Yashiro, Seiji*; Kuwabara, Takao*; Shiota, Daiko*; Kubo, Yuki*
Radiation Protection Dosimetry, 161(1-4), p.274 - 278, 2014/10
Times Cited Count：22 Percentile：85.25(Environmental Sciences)We applied our simulation technique to the analysis of air shower induced by mono-energetic protons and alpha particles, which are the dominant component of SEP. The results of the simulations were summarized in a database containing particle fluxes for each condition as a function of the atmospheric depth. This database was then incorporated into our developing Warning System of AVIation Exposure to SEP called WASAVIES. In this system, the aircrew doses due to SEP exposure are estimated within 6 hours after the flare onset, using the established database multiplied with the SEP fluxes incident to the earth. The MHD Cube model is employed in the determination of the incident SEP fluxes. The procedures for the air shower simulation together with some initial results of the aircrew dose calculations for past ground-level enhancement (GLE) events will be presented at the meeting.
Kataoka, Ryuho*; Sato, Tatsuhiko; Kubo, Yuki*; Shiota, Daiko*; Kuwabara, Takao*; Yashiro, Seiji*; Yasuda, Hiroshi*
Space Weather, 12(6), p.380 - 386, 2014/06
Times Cited Count：19 Percentile：51.8(Astronomy & Astrophysics)Solar energetic particles (SEP) sometimes induce air shower that significantly increase the radiation dose at flight altitudes. In order to inform the situation of such a space radiation hazard to aircrews, a physics-based forward model is developed as WASAVIES (Warning System for Aviation Exposure to SEP) based on the focused transport equation and Monte Carlo particle transport simulation of the air shower. WASAVIES gives the fastest and simplest way to predict the time profile of dose rate during ground-level enhancements (GLEs).
Sato, Tatsuhiko; Yasuda, Hiroshi*; Kataoka, Ryuho*; Yashiro, Seiji*; Kuwabara, Takao*; Shiota, Daiko*; Kubo, Yuki*
no journal, ,
When solar energetic particles (SEP) are incident to the atmosphere, they can induce air showers by generating varieties of secondary particles. Such secondary particles can reach the deep into the atmosphere, and enhance the level of radiation doses. This can be a hazard of aircrews. In order to precisely estimate the radiation doses during large solar particle events, we are developing a warning system of aviation exposure to SEP, WASAVIES. The WASAVIES has been tested and verified by making a comparison between the measured and calculated count rates of several neutron monitors during past GLE (ground level enhancement) events. The final goal of our project is to predict the enhancement of radiation doses due to SEP exposure within 6 hours from the GLE onset.
Sato, Tatsuhiko; Ishii, Mamoru*; Kataoka, Ryuho*; Kubo, Yuki*; Minoshima, Takashi*; Miyoshi, Yoshizumi*; Nagamatsu, Aiko*; Shiota, Daiko*; Takashima, Takeshi*; Yasuda, Hiroshi*
no journal, ,
Forecast of radiation doses for astronauts as well as aircrews due to the exposure to solar energetic particles (SEP) is one of the greatest challenges in space weather research. In last 5 years, we have developed a WArning System for AVIation Exposure to Solar energetic particles: WASAVIES. In this system, the SEP fluxes incident to the atmosphere are calculated by physics-based models, and they are converted to radiation doses using a database developed on the basis of air-shower simulation. However, it takes approximately 2.5 hours to determine the parameters used in the physics-based models after the detection of GLEs, and thus, the current WASAVIES cannot predict doses during the peak of GLEs. Therefore, we are trying to reduce the time for evaluating the parameters, as well as to develop a nowcast system for the radiation dose due to SEP exposure, under the framework of Project for Solar-Terrestrial Environment Prediction (PSTEP) in Japan. A brief outline of WASAVIES together with our future strategy will be presented at the meeting.
Sato, Tatsuhiko; Kataoka, Ryuho*; Yasuda, Hiroshi*; Kubo, Yuki*; Ishii, Mamoru*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*
no journal, ,
Estimation of radiation doses for astronauts as well as aircrews due to the exposure to solar energetic particles (SEP) is one of the greatest challenges in space weather research. We are therefore developing a WArning System for AVIation Exposure to Solar energetic particle (WASAVIES), under the framework of Project for Solar-Terrestrial Environment Prediction (PSTEP). In the system, the SEP fluxes incident to the atmosphere are calculated by physics-based models. Thus, WASAVIES can estimate not only the current value but also time variation of the aircrew doses after a GLE event occurs. A brief outline of WASAVIES together with the status of on-going research subjects such as development of the automatic calculation algorithm will be presented at the meeting.
Sato, Tatsuhiko; Kataoka, Ryuho*; Yasuda, Hiroshi*; Kubo, Yuki*; Ishii, Mamoru*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*
no journal, ,
Estimation of radiation doses for astronauts as well as aircrews due to the exposure to solar energetic particles (SEP) is one of the greatest challenges in space weather research. We are therefore developing a WArning System for AVIation Exposure to Solar energetic particle (WASAVIES), under the framework of Project for Solar-Terrestrial Environment Prediction (PSTEP). In the system, the radiation doses due to SEP exposure at flight altitudes are calculated on the basis of physics-based models and databases with four free parameters, which express the absolute value, power index, and time profiles of SEP fluxes near the sun, and the pitch angle incident to the magnetosphere. Thus, WASAVIES can estimate not only the current value but also time variation of the aircrew doses after a GLE event occurs. A brief outline of WASAVIES together with the status of on-going research subjects such as development of the web-based nowcast and forecast system will be presented at the meeting.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Tsujino, Takashi*
no journal, ,
A ground level enhancement (GLE) event occurred on 10-11 September 2017, associated with X8.2 solar flare exploded at western limb. The magnitude of the GLE was not so large even at the peak, but the duration of the event was longer than average. We briefly report the results of our manually conducted nowcast using WASAVIES (Warning System of AViation Exposure to Solar energetic particles). The maximum radiation dose rate at 12 km flight altitude was estimated to be approximately 2 Sv/h, which is only one-third of the corresponding background dose rate due to the galactic cosmic-ray exposure. This result verified the safety of aircrews and passengers in aviation during this event. The automatic calculation system of WASAVIES was developed, and it will be released via website of Regional Warning Center Japan, International Space Environment Services (RWC Japan, ISES) at NICT in near future.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*
no journal, ,
A physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, is developed for nowcasts and forecasts the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*
no journal, ,
We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*; Ueno, Haruka*; et al.
no journal, ,
Real-time estimation of astronaut doses during solar particle events (SPE) is one of the most challenging tasks in cosmic-ray dosimetry. We therefore develop a new computational method that can nowcast the solar energetic particle (SEP) as well as galactic cosmic-ray (GCR) fluxes on any Earth orbit during a large SPE associating with ground level enhancement. It is an extended version of WArning System for AVIation Exposure to Solar Energetic Particle, WASAVIES. The detailed calculation procedures of WASAVIES-EO will be presented at the meeting, together with the results of its validation based on the experimental data measured in ISS during GLE60, 71 and 72.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Miyoshi, Yoshizumi*
no journal, ,
We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. In this presentation, we will explain details of the web-interface of WASAVIES, which will be released in the near future through the public server of NICT.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*
no journal, ,
We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES is also developed and will be released from March 2019 through the public server of NICT.
Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Miyoshi, Yoshizumi*
no journal, ,
We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES was also developed and released via the public server of NICT.
