机载海洋激光荧光雷达叶绿素a测量性能模拟和初步机载实验

发展机载激光荧光雷达系统测量叶绿素a的浓度,模拟了采用三倍频355 nm波长激光作为激发光,机载海洋激光荧光雷达在不同飞行高度和测量不同深度水层的情况下,测量海表叶绿素a浓度的相对误差。依据模拟的参数建立机载激光荧光雷达系统并进行初步机载实验,获得了同经验数据较为一致的测量结果。     

Wavelength dependence four-wave mixing spectroscopy in a micrometric atomic vapour

This paper presents a theoretical study of wavelength dependence four-wave-mixing (FWM) spectroscopy in a micrometric thin atomic vapour. It compares three cases termed as mismatched case I, matched case and mismatched case II for the probe wavelength less, equal and greater than the pump wavelength respectively. It finds that Dicke-narrowing can overcome width broadening induced by Doppler effects and polarisation interference of thermal atoms, and high resolution FWM spectra can be achieved both in matched and mismatched wavelength for many cases. It also finds that the magnitude of the FWM signal can be dramatically modified to be suppressed or to be enhanced in comparison with that of matched wavelength in mismatched case I or II. The width narrowing and the magnitude suppression or enhancement can be demonstrated by considering enhanced contribution of slow atoms induced by atom-wall collision and transient effect of atom-light interaction in a micrometric thin vapour.     

Damping long waves by a multi-channel structure

In this paper, a multi-channel structure was developed to attenuate waves with various wave periods. By ignoring energy losses and the factor of channel width, a simple and straightforward method was used to tackle this problem. The theoretical solution showed that a single reflected channel structure could attenuate waves of a certain wave period, while a multi-channel structure could attenuate waves with various wave periods. If an interval of 0.05<relative water depth<0.15 is concerned, a structure consisting of four reflected channels could provide a transmission coefficient of less than 0.2. Experimental tests were conducted to verify the theoretical solutions. Both theoretical solution and experimental data indicated that waves with various wave periods would be effectively attenuated after passing through the multi-channel structure. Although some factors are neglected in treating this problem, the method is applicable. An allowed transmission coefficient can be provided by a multi-channel structure only if the computed peak value is not larger than that value.     

一种模拟纠正影像的SAR立体影像匹配方法

针对常规SAR影像匹配方法在地形起伏较大区域无法获取理想的SAR立体影像匹配结果的问题,该文提出了一种基于模拟纠正影像的SAR立体影像匹配方法。利用观测区域粗分辨率DEM进行SAR影像模拟,进而获取几何纠正SAR影像,在几何纠正SAR影像上实现影像匹配,等效于常规基于灰度影像匹配中进行的影像粗配准工作,并且相比于常规粗配准,该等效粗配准过程能够均衡地顾及到整幅影像的像元,最终实现了地形起伏较大区域的高精度SAR立体影像匹配。采用COSMO-Skyped影像数据进行了实验,实验结果表明,匹配精度达到了3个像素左右,比常规的基于灰度影像匹配方法有较大提高,能够有效解决地形起伏较大区域SAR立体影像匹配问题。     

结合空间信息的EDCC测度光谱匹配分类方法

光谱匹配分类方法以光谱相似性测度为分类准则,一种相似性测度只对应于光谱曲线的一种特征,用于光谱匹配分类效果并不好;组合不同类型的相似性测度能够有效改善分类效果,但光谱匹配分类往往忽略了相邻像元间的相关性。为了更好地利用空间信息,提高光谱匹配分类精度,首先组合欧氏距离测度和相关系数测度,得到欧氏距离-相关系数测度;其次通过加入空间乘子,得到结合空间信息的欧氏距离-相关系数测度,从而在光谱匹配分类中增加了空间信息约束。采用两组高光谱影像进行实验验证,结果表明,相比于单一相似性测度及组合相似性测度,结合空间信息的欧氏距离-相关系数测度用于光谱匹配分类能够有效改善分类精度。     

机载InSAR图像配准算法比较研究

复图像配准的关键是选择合适的匹配测度函数,但匹配测度函数对不同地形的适应性有待于研究。本文首先介绍了复相关系数法、实相关系数法、频谱极大值法和平均波动函数法的原理和机载双天线In SAR数据的配准流程,然后分别对比分析4种测度函数在机载In SAR山地和平地数据的精度和可靠性。实验结果表明,复相关系数法和频谱极大值法分别在山地和平地区域获得稳健、高精度的配准结果     

资源三号多光谱影像谱段间相对内参关系标定及高精度配准

针对资源三号多光谱相机,提出利用同时获取的各谱段影像间高精度提取的同名像点建立多光谱相机各谱段对应分片CCD之间的位置模型,求解它们的相对内参关系参数,并应用此模型实现了谱段间影像的高精度谱段配准。试验结果表明该方法能够实现资源三号卫星多光谱影像优于0.3像素精度的谱段间自动配准。     

Crustal Magnetic Studies over Krishna-Godavari Basin in Eastern Continental Margin of India

Total field magnetic data were collected over the Krishna-Godavari basin covering 20, 000 sq.km with an average spacing of 8.5 km. This was mainly to study the long wavelength features related with the deep structures. Aeromagnetic map of the region compared well with the ground maps. The anomaly maps show a combination of NE-SW, NS/NNE-SSW and NW-SE trends. The anomalies of ground data are transformed to isolate the sources at different depths. The second vertical derivative and downward continuation maps bring out clearly the NE-SW and NS/NNE-SSW trends related to the coastal basin and Eastern Ghats implying that they are shallow. These are probably superposed on much deeper NW-SE trending structural features of Pre-Gondwana breakup as evidenced in the Horizontal Gradient of Pseudogravity and upward continuation maps. From the offshore magnetic data it appears that these trends extend up to the Ocean Continent Boundary. It is inferred that the deeper features are associated with rifting of Dharwar and Bastar cratons within the Indian plate, prior to the rifting of India from Gondwanaland. The superposed horst and graben structures are related to the formation of the pull-apart Krishna-Godavari basin as a result of rifting and drifting of India from Gondwanaland. These two structural features are associated with two different tectonic events.     

城市污水处理设施空间格局优化研究——以江苏省淮安市为例

城镇污水处理设施的建设和维护,对现代城市的可持续发展、确保水环境不受污染具有重要意义。以江苏省淮安市为例,以乡镇为评价单元,分析污染源的空间格局、变化趋势及其环境影响、污水处理设施需求,研究城镇污水处理能力与废污水排放的空间匹配格局。综合考虑废污水排放特征、污水处理厂的实际能力与设计能力,利用ArcGIS空间分析工具,将研究区划分为治污潜力释放类型区、治污增强类型区和维持现状类型区,对比分析废污水排放与治理能力缺口,提出污水处理设施建设与运营导向,为城镇污水处理厂建设选址与布局优化提供科学依据。     

特深岩心钻孔套管程序和钻具级配等问题的探讨

讨论了特深岩心钻孔钻探施工的套管程序、钻具及其级配和固井等问题,深入分析了这些技术问题对特深孔钻探施工的风险性和经济性的影响作用。在分析研究的基础上,提出了对我国施工特深岩心钻孔时的套管程序、钻具级配、特深孔钻杆柱、套管柱以及固井等技术方案的建议。