Numerical simulation of wave-induced currents combined with parabolic mild-slope equation in curvilinear coordinates     

崔雷  佟飞飞  石峰 《中国海洋工程》2011,25(3):457-468

Researches on breaking-induced currents by waves are summarized firstly in this paper. Then, a combined numerical model in orthogonal curvilinear coordinates is presented to simulate wave-induced current in areas with curved boundary or irregular coastline. The proposed wave-induced current model includes a nearshore current module established through orthogonal curvilinear transformation form of shallow water equations and a wave module based on the curvilinear parabolic approximation wave equation. The wave module actually serves as the driving force to provide the current module with required radiation stresses. The Crank-Nicolson finite difference scheme and the alternating directions implicit method are used to solve the wave and current module, respectively. The established surf zone currents model is validated by two numerical experiments about longshore currents and rip currents in basins with rip channel and breakwater. The numerical results are compared with the measured data and published numerical results.  相似文献   

基于扩散滤波的多尺度三维变分研究   总被引：4，自引：0，他引：4  

李冬  王喜冬  张学峰  吴新荣  李威  韩桂军 《海洋通报》2011,30(2):165-171

将扩散方程引入三维变分分析,揭示了传统3D-VAR不能有效提取多尺度观测信息的根本原因,即观测导致的目标函数梯度在空间的不连续分布.将扩散滤波融入基于梯度的最优化算法,发展了基于扩散滤波的多尺度3D-VAR.海表面温度数据同化试验结果表明,新方法可从长波至短波有效地提取多尺度的观测信息.  相似文献   

可调节经线收敛度和经纬线间隔的伪圆柱投影          下载免费PDF全文

钟业勋  胡毓钜 《海洋测绘》2011,31(3):8-11

令纬度ψ<,j>转换为ψ<,j>后,中央经线方程用一个ψ<,j>的7次幂方程表示,中央经线方程的系数关联着纬线间隔.令经度λ<,i>转换为ξ<,i>后,赤道方程用一个ξ<,i>的7次幂方程表示,赤道方程的系数关联着经线间隔.经线的收敛度由经线方程的收敛系数调节.由此构建可调节经线收敛度和经纬线间隔的伪圆柱投影.用一实例...  相似文献   

具梯度项的次线性椭圆型方程解的分析     

杨春娜  王建 《中国海洋大学学报(自然科学版)》2011,(Z2):197-201

本文研究了1类具梯度项的次线性椭圆型方程大解和完全有界解的存在性问题。运用上下解方法和极值原理分别得到了Rn上方程存在完全大解的充分必要条件和存在完全有界解的充分条件,并且证明了该方程在Rn中光滑有界区域Ω上不存在大解。  相似文献   

热带风压场平衡特征及其对GRAPES系统中同化预报的影响研究I:平衡特征分析     

王瑞春  龚建东  张林  陆慧娟 《大气科学》2015,39(5):953-966

本文基于GRAPES全球模式的短期预报误差样本,利用赤道波动正规模态研究了热带风、压场平衡特征,并根据这些特征分析了线性平衡方程(LBE)在该区域应用时存在的问题。结果表明:(1)赤道波动能成功解释热带短期预报误差样本的大部分分量,对流层中层为60%~80%,对流层顶和平流层低层为80%以上。(2)在可解释的误差方差中,赤道罗斯贝波(ER)占比仅为30%~55%,其他赤道波动的作用不可忽视。(3)在ER模态基础上引入其他赤道波动会大幅削弱原有风、压场平衡约束,重力惯性波与Kelvin波的作用最为显著。此时,对流层中层位势高度h与u风、v风间的约束接近于零,而平流层低层h-u的平衡特征由Kelvin波主导。(4)LBE主要表达了ER模态下的风、压场平衡特征,与实际情形相比高估了热带风、压场的耦合程度,进一步的改进中需削弱这一虚假平衡,使得热带风、压场分析变得更加独立。  相似文献   

Ronge-Kutta法在计算复杂构造区域地震波旅行时中的应用     

邹长桥  段永红  唐秋惠  徐佼  陈立波 《大地测量与地球动力学》2015,35(5):894-897

采用Ronge-Kutta射线追踪法对地震勘探中几个典型地质模型的地震波射线路径和旅行时计算的实例和效果进行分析。将Ronge-Kutta射线追踪模拟的结果与程函方程计算的时距曲线结果进行对比,验证了Ronge-Kutta射线追踪法的易实现性和程函方程有限差分旅行时算法的强稳定性,表明Ronge-Kutta射线追踪法在复杂构造区域进行地震射线路径和旅行时计算时能得到较好的模拟效果。  相似文献   

基于Landsat TM影像不同地表温度反演算法的比较     

刘冰  包国涛  彭凯  石孟  何环蕾 《地理信息世界》2015,(3)

地表温度是反映地表环境的一个重要参数,精确获取地表温度的方法对研究城市热岛效应、进行生态环境监测评价是必不可少的。利用遥感手段进行地表温度的反演是一种较新颖的方法,相对成熟的反演算法主要有单通道算法、辐射传输方程法及单窗算法。本文以山东省威海市Landsat TM数据为例,分别利用辐射传输方程法和单窗算法进行地表温度反演,通过遥感目视解译的方法提取研究区各类典型地物对应的地表温度,进行统计分析,结果表明,两者反演得到的地表温度具有一致的变化趋势,其中单窗算法中不同典型地物的地表温度整体标准差较小,如建设用地为0.530,起伏波动小,算法精度略优于辐射传输方程法。  相似文献   

Pore characterization of organic-rich Lower Cambrian shales in Qiannan Depression of Guizhou Province,Southwestern China     

《Marine and Petroleum Geology》2015

Nine organic-rich shale samples of Lower Cambrian black shales were collected from a recently drilled well in the Qiannan Depression, Guizhou Province where they are widely distributed with shallower burial depth than in Sichuan Basin, and their geochemistry and pore characterization were investigated. The results show that the Lower Cambrian shales in Qiannan Depression are organic rich with TOC content ranging from 2.81% to 12.9%, thermally overmature with equivalent vitrinite reflectance values in the range of 2.92–3.25%, and clay contents are high and range from 32.4% to 53.2%. The samples have a total helium porosity ranging from 2.46% to 4.13% and total surface area in the range of 9.08–37.19 m²/g. The estimated porosity in organic matters (defined as the ratio of organic pores to the volume of total organic matters) based on the plot of TOC vs helium porosity is about 10% for the Lower Cambrian shales in Qiannan Depression and is far lower than that of the Lower Silurian shales (36%) in and around Sichan Basin. This indicates that either the organic pores in the Lower Cambrian shale samples have been more severely compacted than or they did not develop organic pores as abundantly as the Lower Silurian shales. Our studies also reveal that the micropore volumes determined by Dubinin–Radushkevich (DR) equation is usually overestimated and this overestimation is closely related to the non-micropore surface area of shales (i.e. the surface area of meso- and macro-pores). However, the modified BET equation can remove this overestimation and be conveniently used to evaluate the micropore volumes/surface area and the non-micropore surface areas of micropore-rich shales.  相似文献   

Web2.O环境下基于布鲁克斯方程的地图信息传输模型     

赵晶辉  尹章才  张世伟  李彦鹤  周沂  吴迎霞 《测绘科学》2011,36(6):164-166

各向地图信息传输模型是传统地图信息传输理论在Web2.0时代的延伸与发展,对提升现代地图学的价值具有重要意义.本文通过分析Web2.0地图的特点和相关工作,研究地图制图模式及其相应的地图信息传输模型,引入信息生态学和布鲁克斯方程,重点探索了基于Web2.0地图的各向地图信息传输模型,利用信息学的布鲁克斯方程对Web2....  相似文献   

Diagnostic analysis of the evolution mechanism for a vortex over the Tibetan Plateau in June 2008   总被引：2，自引：0，他引：2  

李论  张人禾  温敏 《大气科学进展》2011,28(4):797-808

Based on the final analyses data (FNL) of the Global Forecasting System of the NCEP and the obser- vational radiosonde data, the evolution mechanism of an eastward-moving low-level vortex over the Tibetan Plateau in June 2008 was analyzed. The results show that the formation of the vortex was related to the convergence between the northwesterly over the central Tibetan Plateau from the westerly zone and the southerly from the Bay of Bengal at 500 hPa, and also to the divergence associated with the entrance re- gion of the upper westerly jet at 200 hPa. Their dynamic effects were favorable for ascending motion and forming the vortex over the Tibetan Plateau. Furthermore, the effect of the atmospheric heat source (Q1) is discussed based on a transformed potential vorticity (PV) tendency equation. By calculating the PV budgets, we showed that Q1 had a great inffuence on the intensity and moving direction of the vortex. In the developing stage of the vortex, the heating of the vertically integrated Q1 was centered to the east of the vortex center at 500 hPa, increasing PV tendency to the east of the vortex. As a result, the vortex strengthened and moved eastward through the vertically uneven distribution of Q1. In the decaying stage, the horizontally uneven heating of Q1 at 500 hPa weakened the vortex through causing the vortex tubes around the vortex to slant and redistributing the vertical vorticity field.  相似文献