Based on the fuzzy local information c-means （FLICM） clustering algorithm, a new method is developed for extracting the equatorward and poleward boundaries of the auroral oval from images acquired by the Ultraviolet...Based on the fuzzy local information c-means （FLICM） clustering algorithm, a new method is developed for extracting the equatorward and poleward boundaries of the auroral oval from images acquired by the Ultraviolet Imager （UVI） aboard the POLAR satellite. First, the method iteratively segments the UVI image with the FLICM clustering algorithm, according to an integrity criterion for the segmented auroral oval. Then, possible gaps in the extracted auroral oval are filled, based on prior knowledge of its shape. To evaluate the method objectively, the extracted boundaries are compared with the precipitating electron boundaries determined from DMSP satellite precipitation particle data. The evaluation results demonstrate that the proposed method generates more accurate auroral boundaries than traditional methods.展开更多
In this study, we developed a summer dayglow model using auroral emissions acquired by the ultraviolet imager （UVI） onboard the Polar satellite. In the summer polar region, dayglow varies as a cosine-like function o...In this study, we developed a summer dayglow model using auroral emissions acquired by the ultraviolet imager （UVI） onboard the Polar satellite. In the summer polar region, dayglow varies as a cosine-like function of the solar zenith angle （SZA）. The shape of this function can be characterized by its amplitude （Amp） and phase （Phi） factors. We first obtained the hourly Amp and Phi factors in summers from 1996 to 2000, and then investigated the universal time （UT） and solar activity variations of these two shape Factors. It was found that both factors were non-linearly dependent on the solar flux for all years, and the Amp factor showed clear UT variations under both low and high solar flux years. Thus, a dayglow model was constructed to consider the above dependencies. After the dayglow was removed automatically from the original UVI images via our model, the remaining auroral precipitation energy flux was in good agreement with previously reported magnetic local time latitude （MLT-MLAT） patterns. Our model provides a fast way to statistically process summer auroral precipitation of Polar/UVI and its variations.展开更多
ST进一步扩大其环境传感器的产品组合,推出可直接数字输出紫外线指数(UVI, Ultraviolet Index)的传感器UVIS25。紫外线指数是在规定时间和地点测量太阳紫外线辐射强度的国际计量标准。过度暴露于紫外线的照射可能导致人体出现暂时性黑斑...ST进一步扩大其环境传感器的产品组合,推出可直接数字输出紫外线指数(UVI, Ultraviolet Index)的传感器UVIS25。紫外线指数是在规定时间和地点测量太阳紫外线辐射强度的国际计量标准。过度暴露于紫外线的照射可能导致人体出现暂时性黑斑,甚至可能引发更严重的病症。紫外线指数是由世界卫生组织(WHO, World Health Organization)展开更多
The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission aims at deepening our understanding of the interaction of the solar wind with the Earth magnetosphere.It is the first time that ESA and CAS jointly s...The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission aims at deepening our understanding of the interaction of the solar wind with the Earth magnetosphere.It is the first time that ESA and CAS jointly select,design,implement,launch,and operate a space mission.The mission was adopted by CAS in November 2016 and by ESA in March 2019 with a target launch date by the end of 2023.展开更多
The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission is a joint space science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS),aiming to understand the interaction ...The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission is a joint space science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS),aiming to understand the interaction of the solar wind with the Earth’s magnetosphere in a global manner.The mission was adopted by CAS in November 2016 and by ESA in March 2019 with a target launch date in the year 2024-2025.We report the recent progress of SMILE mission by May,2022.展开更多
基金supported by the National Natural Science Foundation of China (Grant nos.60872154,41031064,40904041,40974103)the National High Technology Research and Development Program of China (Grant no.2008AA121703)the Ocean Public Welfare Scientific Research Project, State Oceanic Administration of China (Grant no.201005017)
文摘Based on the fuzzy local information c-means （FLICM） clustering algorithm, a new method is developed for extracting the equatorward and poleward boundaries of the auroral oval from images acquired by the Ultraviolet Imager （UVI） aboard the POLAR satellite. First, the method iteratively segments the UVI image with the FLICM clustering algorithm, according to an integrity criterion for the segmented auroral oval. Then, possible gaps in the extracted auroral oval are filled, based on prior knowledge of its shape. To evaluate the method objectively, the extracted boundaries are compared with the precipitating electron boundaries determined from DMSP satellite precipitation particle data. The evaluation results demonstrate that the proposed method generates more accurate auroral boundaries than traditional methods.
基金supported by the National Natural Science Foundation of China (Grant no. 41674154)Fundamental Research Funds for the Central Universities (Grant no. WK2080000077)
文摘In this study, we developed a summer dayglow model using auroral emissions acquired by the ultraviolet imager （UVI） onboard the Polar satellite. In the summer polar region, dayglow varies as a cosine-like function of the solar zenith angle （SZA）. The shape of this function can be characterized by its amplitude （Amp） and phase （Phi） factors. We first obtained the hourly Amp and Phi factors in summers from 1996 to 2000, and then investigated the universal time （UT） and solar activity variations of these two shape Factors. It was found that both factors were non-linearly dependent on the solar flux for all years, and the Amp factor showed clear UT variations under both low and high solar flux years. Thus, a dayglow model was constructed to consider the above dependencies. After the dayglow was removed automatically from the original UVI images via our model, the remaining auroral precipitation energy flux was in good agreement with previously reported magnetic local time latitude （MLT-MLAT） patterns. Our model provides a fast way to statistically process summer auroral precipitation of Polar/UVI and its variations.
文摘ST进一步扩大其环境传感器的产品组合,推出可直接数字输出紫外线指数(UVI, Ultraviolet Index)的传感器UVIS25。紫外线指数是在规定时间和地点测量太阳紫外线辐射强度的国际计量标准。过度暴露于紫外线的照射可能导致人体出现暂时性黑斑,甚至可能引发更严重的病症。紫外线指数是由世界卫生组织(WHO, World Health Organization)
基金Supported by Strategic Priority Program on Space Science,CAS(XDA15350000)National Natural Science Foundation of China(41731070)+1 种基金Key Research Program of Frontier Sciences,CAS(QYZDJ-SSW-JSC028)and Strategic Pionner Program on Space Science,CAS(XDA15052500)。
文摘The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission aims at deepening our understanding of the interaction of the solar wind with the Earth magnetosphere.It is the first time that ESA and CAS jointly select,design,implement,launch,and operate a space mission.The mission was adopted by CAS in November 2016 and by ESA in March 2019 with a target launch date by the end of 2023.
基金Supported by Strategic Priority Program on Space Science,CAS(XDA15350000)National Natural Science Foundation of China(41731070)+1 种基金Key Research Program of Frontier Sciences,CAS(QYZDJ-SSW-JSC028)Strategic Pioneer Program on Space Science,CAS(XDA15052500)。
文摘The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission is a joint space science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS),aiming to understand the interaction of the solar wind with the Earth’s magnetosphere in a global manner.The mission was adopted by CAS in November 2016 and by ESA in March 2019 with a target launch date in the year 2024-2025.We report the recent progress of SMILE mission by May,2022.
