强激光与粒子束
2022, 34(8): 084004
1 南京信息工程大学气象灾害预警与评估协同创新中心, 中国气象局气溶胶与云降水重点实验室, 教育部气象灾害重点实验室, 江苏 南京 210044
2 中国科学院上海光学精密机械研究所空间激光信息传输与探测技术重点实验室, 上海 201800
3 上海卫星工程研究所, 上海 201109
高光谱分辨率激光雷达能够在无需假设激光雷达比的情况下,实现气溶胶光学参数的高精度定量观测。研制了一台用于气溶胶光学特性观测的机载高光谱分辨率激光雷达,并将其用于机载观测试验。针对气溶胶光学参数反演算法进行相应改进,选取不同飞行区域和不同飞行架次的试验数据进行反演,结合太阳光度计、大气污染物输送扩散轨迹模型HYSPLIT和卫星数据等对气溶胶特性进行分析。分析结果表明,不同区域的气溶胶光学参数有明显差异:在城镇、工厂等人类活动频繁的区域,气溶胶的消光系数最高超过1.2 km -1,激光雷达比随高度变化较大,最大可达60 sr,0~3 km高度层的气溶胶光学厚度集中在0.7~1;山区和海洋区域气溶胶的消光系数集中在0.2~0.8 km -1,激光雷达比随高度变化较小,数值集中在5~30 sr,0~3 km高度层的气溶胶光学厚度集中在0.3~0.7。气溶胶的分布受风、天气、污染过程等气象条件的影响,不同日期同一区域的气溶胶光学特性也受大气污染物输送扩散等因素的影响。
遥感 机载高光谱分辨率激光雷达 碘分子滤波器 大气气溶胶 气溶胶光学特性
1 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心/ 中国气象局气溶胶与云降水开放重点实验室,江苏 南京 210044
2 南京信息工程大学大气物理学院,江苏 南京 210044
3 南京信息工程大学大气科学学院,江苏 南京 210044
采用波长插值和时空匹配的方法,对气溶胶自动观测网(aerosol robotic network, AERONET)和风云三号卫星中分辨率光谱成像仪(FY-3A/MERSI) 气溶胶光学厚度(aerosol optical depth, AOD)产品进行匹配,并进一步使用AERONET AOD数据对北京以及周围地区的FY-3A/MERSI AOD产品精 度进行验证分析。实验结果表明: (1)FY-3A AOD与AERONET AOD具有较高的相关性(R=0.733),总体偏低于AERONET AOD(bias=－0.012); (2)下垫面植被覆盖度越高, FY-3A AOD反演精度越高;气溶胶浓度较低精度越高,反之反演精度越低；并且在春冬季节的反演精度高 于夏秋季节。此结论可为北方地区的FY-3A/MERSI气溶胶产品使用提供参考。
气溶胶光学厚度 气溶胶自动观测网 暗像元算法 medium resolution spectral imager MERSI aerosol optical depth aerosol robotic network algorithm of dark target 大气与环境光学学报
2017, 12(6): 435
Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Key Laboratory of Opto-Electronic Information Science and Technology, Ministry of Education, Institute of Modern Optics, Nankai University, Tianjin 300071, China
3 Centre d'Optique, Photonique er Laser (COPL) and Dèpartement de Physique, de Gènie Physique et d'Optique, Universitè Laval, Quèbec, Quèbec G1K 7P4, Canada
With the evolution of a laser pulse in water, the formation of a nonlinear X wave during femtosecond filamentation is investigated based on numerical simulations. In particular, we analyze the far-field angularly resolved spectra obtained for different temporal portions of the ultrashort pulse during its propagation. Our result shows that the refocusing of ultrashort pulse leads to the formation of dynamic X wave which essentially manifests itself as conical emission.
飞秒成丝 脉冲传播 X波 320.0320 Ultrafast optics 190.5530 Pulse propagation and temporal solitons 070.4790 Spectrum analysis Chinese Optics Letters
2010, 8(2): 244
Author Affiliations
Abstract
School of Mechanical and Power Engineering, Shanghai Jiaotong University, Shanghai 200030
A method of image edge detection using the Hopfield neural network (HNN) is proposed in this paper. The image edge parameters are introduced in detail, and the energy function of HNN is given based on the edge parameters. Tests on the image edge detection show that images detected by the proposed method have good edge closeness and true edge, at the same time it has good anti-noise performance. The image edge detection using HNN is better than that obtained by some other edge detection operators.
100.2000 digital image processing 110.2970 image detection systems 100.2960 image analysis 100.3010 image reconstruction techniques Chinese Optics Letters
2004, 2(4): 04213
