NUMERICAL STUDY ON NONLINEAR INTERACTION BETWEEN TROPICAL CYCLONE AND SEA*

Given time-independent monthly mean sea temperature,numerical simulation was done of the path of the tropicalcy clone Forrest and its related physical quantity field in terms of the improved version of the σ-coordinate 10-level primitive equation model for tropical cyclones developed by the Guangzhou Institute of Marine Meteorology.Result ssuggest the similarity between the simulated and observed physical quantity fields except that the simulated path was to the right of the observed,with the deviation increasing with time.Sea and tropical cyclone,in effect,interact mutually.In an attempt to compare the results from coupling and uncoupling experiments,an oceanic mixed layer model was formulated based on experiments with sea response to cyclone and integrated in synchronous coupling with the aforementioned version of tropical cyclones,the computational domain covering the western North Pacific with the coastal configuration involved.The coupling experiment shows that the negative feedback of the interaction between sea and mature cyclone leads to weaker sea response as compared to the uncoupling case.Except for the location of the divergence core of oceanic current,the mixed layer depth and inhomogeneous distribution of sea surface temperature (SST) caused by the cyclone-core position and intensity,the values of the maximum oceanic current,departure of the mixed layer depth and SST drop were smaller in the coupling than in the uncoupling case,and so was the maximum wind near the cyclone core.The path from the coupling run is to the left of the course in the uncoupling experiment but closer to the observed one though remaining somewhat leftward.Even on a scale of less than 3 days,the effects of sea and sea-cyclone interaction on the cyclone were by no means negli-gible.     

Some Splitting Methods for Equations of Geophysical Fluid Dynamics

In this paper, equations of atmospheric and oceanic dynamics are reduced to a kind of evolutionary equation in operator form, based on which a conclusion that the separability of motion stages is relative is made and an issue that the tractional splitting methods established on the physical separability of the fast stage and the slow stage neglect the interaction between the two stages to some extent is shown. Also, three splitting patterns are summed up from the splitting methods in common use so that a comparison between them is carried out. The comparison shows that only the improved splitting pattern (ISP) can be in second order and keep the interaction well. Finally, the applications of some splitting methods on numerical simulations of typhoon tracks made clear that ISP owns the best effect and can save more than 80% CPU time.     

全球大气多层原始方程距平谱模式的研制

距平滤波模式（ＡＦＭ）是具有独特优点的长期天气预报模式，本文推广进而设计了一类全球大气多层原始方程距平谱模式，并利用该模式对热带海温距平产生的大气响应进行了试验性模拟，结果表明多层原始方程距平模式不同于ＡＦＭ，更有别于ＧＣＭ，在短期气候异常的动力学过程研究或预报方面显示出广泛的应用价值。     

AN ATMOSPHERIC MOTION EQUATION BUILT ON THE CONSERVATIVE RELATIONSHIP OF THE ANGULAR MOMENTUM EXCHANGE BETWEEN THE SOLID EARTH AND THE ATMOSPHERE ON SEASONAL-ANNUAL TIMESCALE

Within the seasonal-annual timeseale,there exists an angular momentum conservative exchange relationship be-tween the solid earth and the atmosphere,and their angular momentum exchange not only can cause variations inlength-of-day(LOD)but also can express anomalies in atmospheric general circulation.Therefore,their angular mo-mentum exchange mechanism should be introduced into the general circulation model.Considering the angular momentum anomalous exchange caused by the air-earth interface friction effect,awhole-layer atmospheric motion equation is derived in this paper including the earth spin anomalous friction forceparameterized by using the change in the earth rotation rate.Through analysing the equation,it shows that the magni-tude of the earth spin anomalous friction force is the same as that of Coriolis force on seasonal-annual timescale.     

脉冲式测距仪检测与数据处理理论新探

从脉冲式测距仪的基本原理出发,提出了一种脉冲式测距仪检测的新方法,以及测距值数据预处理的新方法。     

非线性伪双曲方程的第二初边值问题

本文利用Ｌｅｒａｙ－Ｓｃｈａｕｄｅｒ不动点原理和Ｓｏｂｏｌｅｖ估计，证明了非线性伪双曲方程的第二初边值问题整体弱解的存在唯一性，其中ｍ≥１，ａｉ＞０（ｉ＝１，２，３）都是常数。     

NLS EQUATION OF INTERNAL WAVES IN WEAKLY STRATIFIED OCEAN

The NLS (Non-Linear Schr(?)dinger) equation of internal waves in a wekly stratified ocean is der-ived in phase coordnates in terms of the RPM (Reductive Perturbation Method). It was shown thatwhen AB>0 there exist modulation forms of envelope soliton and dn, and tha when AB<0 there arethree modulation forms dark soliton, sn and cn. Only if K~2>B/A(?) . the side-band perturbation is stable,otherwise unstable. For the stable side-band perturbation there ekisis a modulation form of MdV soliton.     

One-way representations of seismic data

A general one-way representation of seismic data can be obtained by substituting a Green's one-way wavefield matrix into a reciprocity theorem of the convolution type for one-way wavefields. From this general one-way representation, several special cases can be derived.
By introducing a Green's one-way wavefield matrix for primaries , a generalized Bremmer series representation is obtained. Terminating this series after the first-order term yields a primary representation of seismic reflection data. According to this representation, primary seismic reflection data are proportional to a reflection operator, 'modified' by primary propagators for downgoing and upgoing waves. For seismic imaging, these propagators need to be inverted. Stable inverse primary propagators can easily be obtained from a one-way reciprocity theorem of the correlation type.
By introducing a Green's one-way wavefield matrix for generalized primaries , an alternative representation is obtained in which multiple scattering is organized quite differently (in comparison with the generalized Bremmer series representation). According to the generalized primary representation, full seismic reflection data are proportional to a reflection operator, 'modified' by generalized primary propagators for downgoing and upgoing waves. Internal multiple scattering is fully included in the generalized primary propagators {either via a series expansion or in a parametrized way). Stable inverse generalized primary propagators can be obtained from the one-way reciprocity theorem of the correlation type. These inverse propagators are the nucleus for seismic imaging techniques that take the angle-dependent dispersion effects due to fine-layering into account.     

一种新的垂直速度计算方法

在流体的不可压缩条件下,本文通过连续方程给出了一种新的垂直速度计算方法,称为z方法。通过实验得出:z方法下同样可以得出水平涡度与垂直运动的关系,即水平涡度矢量逆时针旋转时,对应上升运动,顺时针旋转时对应下沉运动。通过有效性验证得出:本文的方法在高层具有比较高的可靠性,在低层可靠性比高层稍弱,在中层则不甚理想。通过与p方法求解出的垂直速度的效果进行比较,得出p方法略好于z方法。     

A New Temperature Channel Selection Method Based on Singular Spectrum Analysis for Retrieving Atmospheric Temperature Profiles from FY-4A/GIIRS

Hyperspectral data have important research and application value in the fields of meteorology and remote sensing.With the goal of improving retrievals of atmospheric temperature profiles, this paper outlines a novel temperature channel selection method based on singular spectrum analysis(SSA) for the Geostationary Interferometric Infrared Sounder(GIIRS), which is the first infrared sounder operating in geostationary orbit. The method possesses not only the simplicity and rapidity of the principal component analysis method, but also the interpretability of the conventional channel selection method. The novel SSA method is used to decompose the GIIRS observed infrared brightness temperature spectrum(700-1130 cm~(-1)), and the reconstructed grouped components can be obtained to reflect the energy variations in the temperature-sensitive waveband of the respective sequence. At 700-780 cm~(-1), the channels selected using our method perform better than IASI(Infrared Atmospheric Sounding Interferometer) and Cr IS(Cross-track Infrared Sounder)temperature channels when used as inputs to the neural network retrieval model.