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北半球湖冰厚度的现状及未来 被引量:3
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作者 李兴东 龙笛 +1 位作者 黄琦 赵凡玉 《Science Bulletin》 SCIE EI CSCD 2022年第5期537-546,M0004,共11页
湖冰厚度是对气候变化高度敏感的指示因子,通过影响湖泊与大气之间的物质能量交换,调节区域水文气候和湖泊生态系统,并对维系冰上生产生活至关重要.由于实测湖冰厚度资料极度匮乏,同时缺乏高效的遥感观测手段,大范围湖冰厚度的时空演变... 湖冰厚度是对气候变化高度敏感的指示因子,通过影响湖泊与大气之间的物质能量交换,调节区域水文气候和湖泊生态系统,并对维系冰上生产生活至关重要.由于实测湖冰厚度资料极度匮乏,同时缺乏高效的遥感观测手段,大范围湖冰厚度的时空演变规律还存在空白.现有的全球湖冰数据主要利用湖冰模型基于再分析气象驱动场和虚拟湖泊生成,难以反映真实湖冰厚度.本研究使用卫星雷达测高反演了北半球16个大型湖泊和水库过去近30年的冰厚,精度约为0.2m.在此基础上开发并验证了遥感数据驱动的湖冰模型,模拟了北半球大于50 km^(2)的1313个湖泊和水库(湖库总面积约840,000 km^(2))的冰厚,估算了2003~2018年北半球多年平均最大冰厚为0.63 m,相当于485 Gt水当量.以该时段冰厚为参考,预估了在RCP 8.5情境下未来(2071~2099年)最大冰厚可能减小约0.35 m,北半球湖冰变薄将对区域水文气候和湖泊生态系统,以及冰上交通等社会经济活动造成重大影响. 展开更多
关键词 区域水文 冰厚 湖泊生态系统 时空演变规律 遥感观测 指示因子 水当量 气候变化
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Denoising method of X-ray phase contrast DR image for TRISO-coated fuel particles 被引量:2
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作者 Min Yang Jianhai Zhang +4 位作者 Fanyong Meng Sung-Jin Song xingdong li Wenli liu Dongbo Wei 《Particuology》 SCIE EI CAS CSCD 2013年第6期695-702,共8页
TRISO (tristructural-isotropic) fuel is a type of micro fuel particles used in high-temperature gas-cooled reactors (HTGRs). Among the quality evaluation methods for such particles, inqine phase contrast imaging t... TRISO (tristructural-isotropic) fuel is a type of micro fuel particles used in high-temperature gas-cooled reactors (HTGRs). Among the quality evaluation methods for such particles, inqine phase contrast imaging technique (PCI) is more feasible for nondestructive measurement. Due to imaging hardware limitations, high noise level is a distinct feature of PCI images, and as a result, the dimensional measurement accuracy of TRISO-coated fuel particles decreases. Therefore, we propose an improved denoising hybrid model named as NL P-M model which introduces non-local theory and retains the merits of the Perona-Malik (P-M) model. The improved model is applied to numerical simulation and practical PCI images. Quanti- tative analysis proves that this new anisotropic diffusion model can preserve edge or texture information effectively, while ruling out noise and distinctly decreasing staircasing artifacts. Especially during the process of coating layer thickness measurement, the NL P-M model makes it easy to obtain continuous contours without noisy points or fake contour segments, thus enhancing the measurement accuracy. To address calculation complexity, a graphic processing unit (GPU) is adopted to realize the acceleration of the NL P-M denoising. 展开更多
关键词 TRISO-coated fuel particle X-ray phase contrast imaging Image denoising Partial differential equation Non-local means
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