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太空天氣預報

太空天氣預報. 為什麼要做太空天氣預報 太空天氣預報中心與預報內容 如何做太空天氣預報與預報模式. How do Magnetic Storms Form?.

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太空天氣預報

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  1. 太空天氣預報 • 為什麼要做太空天氣預報 • 太空天氣預報中心與預報內容 • 如何做太空天氣預報與預報模式

  2. How do Magnetic Storms Form? All magnetic fields have a direction. The solar wind’s field can point in all sorts of directions: towards Earth, away from Earth, towards the north, towards the south, and even towards the east and west. The actual direction of the field when a mass ejection comes crashing into Earth’s magnetosphere is very important. If it’s directed southward, we have found that disturbances in the solar wind, like CMEs, can penetrate Earth’s protective shield and cause magnetic storms. If the solar wind’s magnetic field has some other direction, like northward, then conditions are mild. The direction of the field acts like an electric switch: northward the switch is off; southward it is turned on.

  3. Space Weather: Early Warnings (1) Like meteorologists who check temperatures, winds, and pres sure to predict the weather on Earth, scientists monitor the Sun and our space environment to forecast the weather in space. Using spacecrafts like SOHO, Earth-based telescopes, and old-fashioned hand sketches of the Sun, scientists search the surface of the Sun for signs of flares and CMEs. They monitor the solar wind as it blows toward Earth to see if it is carrying foul weather, and they measure the energy flowing into Earth’s upper atmosphere and the distortion of magnetic fields near the ground. From these bits of information, NOAA’s Space Environment Center forecasts whether our space weather will be mild or wild.

  4. Space Weather: Early Warnings (2) Utilizing a fleet of spacecraft, scientists in dozens of countries observe the Sun, the solar wind, the near-Earth space environment, as well as the aurora. Ground-based telescopes, radar and supercomputers are used alongside these spacecraft to provide a picture of current and future space weather conditions. We are learning what it means to truly live within the atmosphere of the Sun.

  5. 太空天氣預報中心與預報內容 • 美國太空天氣預報中心(SWPC) • 日本國家資訊通訊技術研究所(NICT) • 歐洲航太總署(ESA) • 中國國家空間天氣監測預警中心

  6. Space weather forecast (1) • Space weather forecasts and alerts are issued by NOAA's Space Weather Prediction Center (SWPC), located in Boulder, Colorado. • SWPC receives space weather data from many different satellites and ground-based stations around the world. Forecasters track Sunspots, map coronal holes and provide a detailed description of all active regions visible on the solar disk.

  7. Space weather forecast (2) The face of the turbulent Sun, as seen here in Hydrogen-alpha wavelengths, is far more violent than most people suppose. Hydrogen-alpha is an absorption line of neutral hydrogen in the red part of the visible spectrum. It is used to characterize solar flares, filaments, prominences, and the fine structure of active regions.

  8. Space weather forecast (3) Sunspot Groups, like those seen as dark areas in visible-light images of the Sun, are also responsible for X-ray emissions. These are active regions where hot, dense plasmas are energized. They are also associated with regions of oppositely directed magnetic fields which can erupt as a solar flare and coronal mass ejection.

  9. Space weather forecast (4) Forecasters in the SEC monitor the near-Earth space environment. Solar flares produce vast amounts of X-rays and energetic protons which can be detected by NOAA satellites orbiting at geosynchronous altitudes and around the poles. Energetic particles from the Sun and energized plasma in Earth's radiation belt environment can cause damage to satellites.

  10. SWPC Real Time Observations Solar Wind Activity

  11. Auroral Activity

  12. 太空天氣預報模式 • 太陽表面活動模式 • 太陽風模式 • 船頭震波與磁層頂模式 • 磁層模式 • 電離層模式

  13. Solar Wind Modeling 以經驗或數學模式，推估未來的太陽風速度與行星際磁場方向，或用以預測太陽爆發事件是否會引發衝擊地球的行星際震波，若是，則該震波何時抵達地球，以及其強度大小為何？ • Wang-Sheeley Model • Kinematic Solar Wind Model (HAF) • NOAA/USAF STOA and ISPM Models

  14. The Wang-Sheeley Model • The Wang-Sheeley Model predicts the background solar wind speed and the interplanetary magnetic field (IMF) polarity at earth, two important parameters required for predicting geomagnetic activity.

  15. HAF model • Hakamada-Akasofu-Fry (HAF)太陽風程式碼是由阿拉斯加大學地球物理研究所 (Geophysical Institute, University of Alaska, Fairbanks) 與 Exploration Physics International, Inc. (EXPI) 持續發展中。 • HAF 模式是一套修正的運動數學(modified kinematic)模式， “Kinematic” 是指利用運動學方法計算源自於太陽表面附近不均勻的太陽風吹入行星際空間的流動。“Modified” 則指當高速流追上低速流時，發生流與流交互作用下對於太陽風流動的調整。 • 不同於MHD 模式對運動方程式直接積分來計算太陽風速度大小，運動數學模式則是先以方程式的兩次積分取得流體塊的位置，再由位置隨時間的變化dx/dt算出速度。

  16. GSE ForecastsGeoeffectiveness of Solar Events 利用HAF model 模擬預測行星際磁場結構的變化

  17. NOAA/USAF STOA and ISPM models • The Shock Time of Arrival(STOA) model and the Interplanetary Shock Propagation Model(ISPM) have been developed for the purpose of predicting the time of arrival and strength of solar-initiated interplanetary shocks. • The STOA model is based on similarity theory of blast waves, modified by the piston-driving concept, that emanate from point explosions. • The ISPM is based on a 2.5 D MHD parametric study of numerically simulated shocks.

  18. Tsyganenko magnetospheric model 隨地磁軸的指向改變

  19. 隨穩定行星際南向磁場的變化

  20. 隨動態行星際磁場與太陽風變動的磁層 --- 磁暴與磁副暴

  21. MHD simulation

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