星载极化相关型全极化微波辐射计天线交叉极化校正技术 (II) : 校正试验

创建了地球场景数据集, 结合全极化微波辐射传输模型, 仿真了地球场景亮温. 基于自主推导的全极化天线温度方程, 通过GRASP9软件生成天线方向图, 模拟了辐射计的天线温度. 进而利用多元线性回归方法, 求取了天线交叉极化校正M矩阵, 实现了对星载极化相关型全极化微波辐射计天线交叉极化的校正. 试验结果表明: 天线温度与地球场景亮温之间具有良好的线性关系; 天线交叉极化对全极化微波辐射计正交通道亮温影响明显, 尤其以对垂直极化亮温误差的影响最为显著; 校正后各通道的天线交叉极化得到了有效的减小, 交叉极化优于-23 dB, 极化纯度大于99.5%, 采用M矩阵校正及消除天线温度中交叉极化亮温影响的方案是切实可行的. 该校正技术可以实现星载极化相关型全极化微波辐射计在轨运行后对于天线交叉极化的最终校正. 关键词： 全极化微波辐射计 天线交叉极化 天线温度方程 M矩阵')" href="#">M矩阵     

全极化微波辐射计姿态对观测亮温的影响及消除

针对全极化微波辐射计精确探测的需求, 研究了辐射计姿态对于观测亮温的影响以及亮温误差校正. 建立了姿态偏移与观测入射角以及极化旋转角的关系, 模拟了观测亮温随观测入射角以及极化旋转角波动的变化; 仿真了姿态偏移情况下的辐射计原始观测亮温;运用一种基于辐射传输模型的姿态补偿方法, 以垂直极化亮温和第三Stokes参数亮温为例, 对原始观测亮温展开误差校正. 研究显示, 该方法能够有效去除辐射计姿态偏移对观测亮温造成的影响, 校正结果满足辐射计数据预处理的误差精度要求. 关键词： 全极化微波辐射计 Stokes参数 观测入射角 极化旋转角     

无云情况下L波段微波辐射计快速大气校正方法

利用数值天气预报模式输出的大气温湿廓线数据与大气辐射传输模型计算了无云情况下全球海面大气在L波段的上行、下行辐射亮温及透射率, 建立三个参数与大气水汽含量及海表气压的回归关系模型——辐射-水汽模型, 利用该模型可快速计算大气辐射参数, 对L波段微波辐射计进行大气校正. 为了验证模型的实用性和可靠性, 利用SSM/I卫星水汽含量数据和数值模式地表气压数据通过模型计算大气辐射参数, 并与Aquarius卫星实测L波段微波辐射数据进行对比分析. 结果表明: 模型计算的辐射亮温比卫星观测数据偏低约0.335 K, 但改正系统性偏差后的均方根误差仅0.086 K, 且模型计算的大气透射率与卫星观测数据基本一致, 说明利用该模型对L波段微波辐射计进行大气校正具有较高的可靠性, 相比于传统利用大气辐射传输模型进行大气校正, 该模型更为简单快速, 输入参数更易获取, 更适于工程应用.     

The evans-vigier field,B (3): Derivation of the de Broglie matter-wave equation from the Hamilton-Jacobi equation

The emergence of the Evans-Vigier fieldB ⁽³⁾ of vacuum electromagnetism has been accompanied by a novel charge quantization condition inferred from 0(3) gauge theory. This finding is used to derive the de Broglie matter-wave equation from the classical Hamilton-Jacobi (HJ) equation of one electron in the electromagnetic field. The HJ equation is used with the charge quantization condition to show that, in a perfectly elastic photon-electron interaction, complete transfer of angular momentum occurs self-consistently, and the electron acquires the angular momentum of the photon. In this limit the electron travels infinitesimally near the speed of light, and its concomitant electromagnetic fields become indistinguishable from those of the uncharged photon. This result independently proves the validity of the charge quantization condition and demonstrates unequivocally the existence of the vacuum fieldB ⁽³⁾.     

Exact solution and exotic coherent solition structures of the （2＋1）—dimensional generalized nonlinear Schroedinger equation

In this paper,a variable separation approach is used to obtain localized coherent structures of the (2 1)-dimensional generalized nonlinear Schroedinger equation:Iφt-(α-β）φxx (α β）φyy-2λφ[（α β）（∫-∞^x|φ|y^2ydx u1(y,t))-(α-β）(∫-∞^y|φ|x^2dy u2(x,t))]=0,By applying a special Baecklund transformation and introducing arbitrary functions of the seed solutions,the abundance of the localized structures of this model are derived.By selecting the arbitrary function appropriately,some special types of localized excitations such as dromions,dromion lattice,breathers and istantons are constructed.     

Derivation of the vacuum longitudinal fieldB (3) from the Dirac equation of the electron in the electromagnetic field

By solving the Diras equation for the motion of an electron (c) in the circularly polarized electromagnetic field it is shown that the intrinsic electron spin forms an interaction Hamiltonian with a time independent fieldB ⁽³⁾ of electromagnetic radiation in the vacuum. In the same way as intrinsic spin is a fundamental property of the electron,B ⁽³⁾ is therefore a fundamental and intrinsic property of the vacuum electromagnetic field.     

Investigation on the resonance phenomena of multi-solitons for the （3＋1）-dimensional Kadomtsev-Petviashvili equation

In this paper, we theoretically investigate the four-soliton interaction and their resonance phenomena of the (3+1)-dimensional Kadomtsev--Petviashvili (KP) equation. We find that the maximum amplitude of the resonantly created soliton can be 16 times that of one of the four equi-amplitude initial interacting solitons. We also find that the maximum amplitude can only be 4 times the initial soliton amplitude when the resonance phenomena does not take place. The case of four solitons with different amplitudes also has been studied analytically. The results indicate that the resonance phenomena still exists in this case. Numerical results confirm the theoretical predictions.     

谐振子薛定谔方程的超对称解法

通过构造哈密顿量与谐振子系统哈密顿量对易的超对称系统,量子谐振子的性质就可以通过对超对称系统的研究来得到.利用超对称系统的性质,在没有用到厄米多项式的情况下,给出了谐振子本征函数中展开系数间的递推关系,由递推关系可以直接得到本征函数.此方法下得到的归一化本征函数与用厄米多项式表达的本征函数完全相同,并且本征函数的宇称可以明显的显示出来.     

An FDTD scheme on a face-centered-cubic (FCC) grid for the solution of the wave equation

A method is proposed to improve the numerical dispersion characteristics for simulations of the scalar wave equation in 3D using the FDTD method. The improvements are realized by choosing a face-centered-cubic (FCC) grid instead of the typical Cartesian (Yee) grid, which exhibits non-physical distortions of the wavefront due to the FD stencil. FCC grids are the logical extension of hexagonal grids in 2D, and have been shown previously to provide optimal sampling of space based on close packing of spheres (highest density). The difference equations are developed for the wave equation on this alternative grid, and the dispersion relationship and stability for grids of equal and non-equal aspect ratios are derived. A comparison is made between FCC and Cartesian formulations, based upon having an equal volume density of gridpoints in each method (i.e. the computational storage requirements of each method would be the same for the same simulated space). The comparison shows that the FCC grid exhibits a much more isotropic dispersion relation than the Cartesian grid of equivalent density. Furthermore, for an equivalent density, the FCC method has a more relaxed stability criterion by a factor of approximately 1.35, resulting in a further reduction in computational resources.     

Two classes of fractal structures for the （2＋1）-dimensional dispersive long wave equation

Using the mapping approach via a Riccati equation, a series of variable separation excitations with three arbitrary functions for the (2+1)-dimensional dispersive long wave (DLW) equation are derived. In addition to the usual localized coherent soliton excitations like dromions, rings, peakons and compactions, etc, some new types of excitations that possess fractal behaviour are obtained by introducing appropriate lower-dimensional localized patterns and Jacobian elliptic functions.