机载激光雷达测深是近年来蓬勃发展的主动式水深测量方法,能够快速精准地获取近岸水深和水下地形,特别是对于浅海、岛礁等船只无法达到的区域具有显著优势。而机载激光雷达系统的测深能力主要受到水体浑浊度的影响。激光测深实验中对实...机载激光雷达测深是近年来蓬勃发展的主动式水深测量方法,能够快速精准地获取近岸水深和水下地形,特别是对于浅海、岛礁等船只无法达到的区域具有显著优势。而机载激光雷达系统的测深能力主要受到水体浑浊度的影响。激光测深实验中对实验区域的水体浑浊度研究将有助于实验方案的设计。以中国海南岛沿岸海域为例,研究了该海域水体浑浊度和机载激光雷达测深系统CZMIL(coastal zone mapping and imaging LiDAR)测深能力之间的关系,建立了运用水体漫衰减系数估算机载激光雷达测深系统测深能力的算法。首先分析并确定了实验区域的漫衰减系数K_d(490)反演算法;其次,运用该区域实测光学数据建立了漫衰减系数K_d(490)和K_d(532)之间的数值关系;接着总结了K_d(532)和CZMIL系统最大测深值之间的关系;最后运用MODIS数据合成了海南岛沿岸海域在CZMIL系统海道测量模式下的测深能力空间分布图,重点分析了海口和陵水附近海域的最大可测水深分布情况。为海南岛沿岸海域开展激光测深实验提供了参考和依据。展开更多
The prediction skill of Arctic Oscillation (AO) in the decadal experiments with the Beijing Climate Center Climate System Model version 1.1 (BCC_CSM1.1) is assessed. As compared with the observations and historical ex...The prediction skill of Arctic Oscillation (AO) in the decadal experiments with the Beijing Climate Center Climate System Model version 1.1 (BCC_CSM1.1) is assessed. As compared with the observations and historical experiments, the contribution of initialization for climate model to predict the seasonal scale AO and its interannual variations is estimated. Results show that the spatial correlation coefficient of AO mode simulated by the decadal experiment is higher than that in the historical experiment. The two groups of experiments reasonably reproduce the characteristics that AO indices are the strongest in winter and the weakest in summer. Compared with historical experiments, the correlation coefficient of the monthly and winter AO indices are higher in the decadal experiments. In particular, the correlation coefficient of monthly AO index between decadal hindcast and observation reached 0.1 significant level. Furthermore, the periodicity of the monthly and spring AO indices are achieved only in the decadal experiments. Therefore, the initial state of model is initialized by using sea temperature data may help to improve the prediction skill of AO in the decadal prediction experiments to some extent.展开更多
文摘机载激光雷达测深是近年来蓬勃发展的主动式水深测量方法,能够快速精准地获取近岸水深和水下地形,特别是对于浅海、岛礁等船只无法达到的区域具有显著优势。而机载激光雷达系统的测深能力主要受到水体浑浊度的影响。激光测深实验中对实验区域的水体浑浊度研究将有助于实验方案的设计。以中国海南岛沿岸海域为例,研究了该海域水体浑浊度和机载激光雷达测深系统CZMIL(coastal zone mapping and imaging LiDAR)测深能力之间的关系,建立了运用水体漫衰减系数估算机载激光雷达测深系统测深能力的算法。首先分析并确定了实验区域的漫衰减系数K_d(490)反演算法;其次,运用该区域实测光学数据建立了漫衰减系数K_d(490)和K_d(532)之间的数值关系;接着总结了K_d(532)和CZMIL系统最大测深值之间的关系;最后运用MODIS数据合成了海南岛沿岸海域在CZMIL系统海道测量模式下的测深能力空间分布图,重点分析了海口和陵水附近海域的最大可测水深分布情况。为海南岛沿岸海域开展激光测深实验提供了参考和依据。
基金National Natural Science Foundation of China (41790471, 41175065)National Key Research and Development Program of China (2016YFA0602200, 2012CB955203, 2013CB430202).
文摘The prediction skill of Arctic Oscillation (AO) in the decadal experiments with the Beijing Climate Center Climate System Model version 1.1 (BCC_CSM1.1) is assessed. As compared with the observations and historical experiments, the contribution of initialization for climate model to predict the seasonal scale AO and its interannual variations is estimated. Results show that the spatial correlation coefficient of AO mode simulated by the decadal experiment is higher than that in the historical experiment. The two groups of experiments reasonably reproduce the characteristics that AO indices are the strongest in winter and the weakest in summer. Compared with historical experiments, the correlation coefficient of the monthly and winter AO indices are higher in the decadal experiments. In particular, the correlation coefficient of monthly AO index between decadal hindcast and observation reached 0.1 significant level. Furthermore, the periodicity of the monthly and spring AO indices are achieved only in the decadal experiments. Therefore, the initial state of model is initialized by using sea temperature data may help to improve the prediction skill of AO in the decadal prediction experiments to some extent.
