基于MODIS遥感数据的水体提取模型及算法改进

针对MODIS遥感数据采用多波段谱间关系模型提取水体容易与阴影混淆,产生提取不精确的问题,作者改进了模型中的水体提取算法,然后对鄱阳湖的MODIS遥感数据进行水体提取实验。最终,实验结果表明,改进后的水体提取算法能够有效地提升水体提取精度。该方法现已运用到一些采用MODIS数据进行水体监测与提取的实践作业中。     

带状区域不等格网间距DEM的拼接与显示研究

数字高程模型是数字地形模拟的重要成果,作为空间数据框架中的主要内容,也成为各种地理信息的载体。在铁路、城轨、公路等线形构筑物的设计和建设中,沿线两边的地形信息是工程设计和建设的基础。本文结合带状区域的特点以及数字高程模型本身的特点,从工程实用的角度出发,围绕带状区域中多块不等采样间隔DEM数据在工程应用中的问题,重点分析了多块不等采样间隔DEM之间拼接的问题,确定了一种不等采样间隔的DEM间无缝拼接的方法,简单介绍了多块不等间隔数字高程模型的裁剪方法和三维可视化方法。     

不同孔径筛网对底栖多毛类采样效果的研究

本文根据大亚湾50个站底栖生物生态调查资料,对孔径1mm和0.5mm筛网中多毛类的种类数、主要种、平均密度、平均生物量进行比较分析。结果表明,孔径1mm的为14种/站、9种、110个/m~2和8.03g/m~2,而0.5mm为22种/站、12种、216个/m~2和0.71g/m~2;1mm筛网多毛类密度(X)与0.5mm的密度(Y)呈线性正相关关系,其回归方程为:Y=0.93X+113.77;在估算海域生产力中,应当使用0.5mm孔径筛网。     

Utility of an automatic water sampler to observe seasonal variability in nutrients and DIC in the Northwestern North Pacific

Concentrations of nutrients (NO₃, NO₂, Si(OH)₄, PO₄ and dissolved inorganic carbon (DIC) were measured in a series of seawater samples collected over approximately 15 months in 2005 and 2006 by an automatic water sampler (Remote Access Sampler, RAS) in the Northwestern North Pacific. Seasonal variability and concentrations of NO₃ + NO₂ (NO_x and Si(OH)₄ were comparable to previous shipboard observations, although there were small errors associated with measurements of PO₄ and DIC. Concentrations of these nutrients began to decrease in late April. After the end of June, NO_x and Si(OH)₄ decreased rapidly, with large fluctuations. After October, these nutrients increased again until late spring 2006. The ratio of the decrease of Si(OH)₄ to that of NO_x suggests that numbers of biogenic opal-producing creatures, such as diatoms, increased after the end of June. This conclusion was supported by a rapid increase in biogenic opal flux recorded in a sediment trap at 150 m. The relationship between NO_x concentrations at the RAS depth of 35 m and NO_x integrated over the upper 100 m was determined using previous shipboard hydrocast data. This relationship was used to estimate integrated mixed layer NO_x concentration from RAS data. Estimated new production based on seasonal drawdown of integrated NO_x averaged approximately 156 mg-C m⁻²day⁻¹ annually, which agrees with previous estimates. Thus, an automatic seawater sampler that documents annual maximum and minimum nutrient concentrations and episodic events such as storms and spring blooms, which might be missed by an ordinary research vessel, will contribute to time-series observations of nutrients and, by extension, biological pump activity.     

大洋底质调查钢丝绳的倾斜校正

根据“东方红 2”调查船 3次大洋底质调查获得的实放钢丝绳长度、钢丝绳倾斜角度、船舶漂移速度等数 1 0个实测数据 ,通过统计分析得到了放钢丝绳长度与钢丝绳倾斜角度之间的经验关系公式。依据该经验公式进行倾斜校正比用余弦法进行校正少放钢丝绳数百至一千多米。该公式适用条件 :水深 2 0 0 0～ 6 0 0 0 m,钢丝绳倾角 0～ 5 5°     

海洋和海岸工程可靠度分析的几个问题

研究可靠度分析中的几个重要问题：１．直接求解非高斯过程、具有不同相关性的多变量情况下的结构失效概率问题；２．荷载的不确定性分析及其订正；３．荷载的相关性对结构失效概率的影响及灵敏度分析．作为实例对直立堤和导管架平台进行计算．