On the calculation of perturbations in the radial position of satellites

With the aim of analyzing the errors in the radial position of satellites, we give in this paper the expressions for the radial perturbation which include the complete zeroth- and first-order terms in the orbital eccentricity. A simpler and faster method of calculating the perturbation is given.     

FARMLAND AND URBAN AREA DYNAMICS MONITORING INCHINA USING REMOTE SENSING AND SPATIALSTATISTICS METHODOLOGY

1 INTRODUCTIONGlobal change research involves much geo-objectsand geo-process, such as climate and environmentalchange, substance and energy cycling, land-use/land-cover change (LUCC), interactivity between human and nature, etc.. So it need cooperation frommany research communities including international research programs groups such as IGBP (InternationalGeosphere-Biosphere Programme IPCC (Intergovemmental Panel on Climate Change), IHDP (InternationalHuman Dimension Program o…     

三维抛物方程Douglas交替方向隐格式的稳定性和收敛性

作者研究三维变系数抛物方程 Douglas交替方向隐格式的稳定性和收敛性。采用 H1能量估计方法 ,证明格式按离散 H1范数是绝对稳定的 ,并且收敛阶为 O(Δ t2 + h2 )     

胶州湾海域水质预测

在已建潮流模型的基础上,用ADI法建立了胶州湾扩大域变动边界的平流—扩散输运模型,以COD为指示因子,预测了胶州湾海域1995年、2000年的水质、青岛环海公路海上段、沧口区北半部污水截流、北水南调、集中排放以及胶州湾西部经济开发对海域水质的影响等。为青岛市环保部门制定环保规划提供决策依据。     

A Compact Explicit Difference Scheme of High Accuracy for Extended Boussinesq Equations

Presented here is a compact explicit difference scheme of high accuracy for solving the extended Boussinesq equations.For time discretization,a three-stage explicit Runge-Kutta method with TVD property is used at predicting stage,a cubic spline function is adopted at correcting stage,which made the time discretization accuracy up to fourth order;For spatial discretization,a three-point explicit compact difference scheme with arbitrary order accuracy is employed.The extended Boussinesq equations derived by Beji and Nadaoka are solved by the proposed scheme.The numerical results agree well with the experimental data.At the same time,the comparisons of the two numerical results between the present scheme and low accuracy difference method are made,which further show the necessity of using high accuracy scheme to solve the extended Boussinesq equations.As a valid sample,the wave propagation on the rectangular step is formulated by the present scheme,the modelled results are in better agreement with the experimental data than those of Kittitanasuan.     

Numerical study of the summer temperature decrease induced by the enhancement of estuarine circulation in Fukuoka Bay

The Princeton Ocean Model with realistic bottom topography has been used to investigate the summer temperature decrease in the past 25 years in Fukuoka Bay. The vertical mixing of the model is expressed by a scheme that effectively includes the influences of interannual variations of tidal currents and wind. The results show that the historical temperature decrease in summer has been caused by tidal currents and wind weakening in the past 25 years in Fukuoka Bay. The weakening of tidal currents and wind gives rise to weakening of the vertical mixing, and to enhancement of the estuarine circulation in the bay. The enhancement of the estuarine circulation activates the inflow of open-ocean water toward Fukuoka Bay. Coastal water in summer has therefore tended to be colder and more saline in the past 25 years. This interannual variation in coastal waters is called “open-oceanization” in this study. On the basis of the numerical model, it is anticipated that the temperature will decrease by 0.2°C in the next 25 years in Fukuoka Bay if the tide and wind weaken persistently as in the present bay.     

具有匹配不确定的奇异摄动系统的鲁棒控制

对于同时具有结构匹配不确定和系统不确定量的奇异摄动系统，利用Lyapunov稳定性理论进行了鲁棒性研究。给出了1个理想奇异摄动系统的稳定鲁棒控制也是不确定奇异摄动系统稳定控制的稳定条件和鲁棒界，讨论了鲁棒界及其随参数变化的变化范围。本文是王宪杰，高存臣已有结果的推广。     

北部湾三维风生流及密度流模拟

将Casulli差分格式引入三维物理海洋模型计算，模拟了北部湾风生流及密度流。模拟结果表明，夏季西南季风在北部湾导致一个顺时针环流，夏季海水密度梯度导致一个逆时针方向的环流，密度流明显强于风生流；冬季东北寒潮导致一个逆时针环流。模拟结果不支持北部湾夏季为一顺时针环流、冬季为逆时针环流的传统结论，而支持终年为逆时针环流的观点。     

二次特征值问题的最佳向后扰动分析

二次特征值问题 (QEP)的主要的求解方法之一是转化为广义特征值问题 (GEP) ,然后用求解广义特征值的方法 (比如 QZ方法 )求解。本文研究由此获得的计算解的范数意义下的最佳向后扰动分析 ,所得结果是 Tisseur最近所得结果的加强。