正压大气模式中在地形效应和β效应作用下的非线性Rossby包络孤立波

在正压大气模式下,采用多重尺度法研究了基本气流具有弱切变的正压非线性Rossby孤立波包,得到了当波振幅和纬向波数都是缓变情况下Rossby波包振幅的演变满足带有β效应和小尺度地形作用的非线性非齐次Schrdinger方程.说明β效应和地形效应是诱导Rossby包络孤立波的重要因素.     

完整Coriolis力作用下的非线性Rossby波包

在正压流体中,从准地转正压涡度方程出发,运用时空伸长变换和摄动法推导了在完整Coriolis力作用下的非线性Rossby孤立波包振幅的演变满足非齐次非线性Schrodinger方程的结论.结果分析表明,完整Coriolis力中的水平分量对Rossby孤立波产生一定的影响,同时,β效应和地形效应也是诱导Rossby孤立波产生的重要因素.     

弱二次切变基本流下地形和β变化的Rossby孤立波

在正压流体中从包含地形的准地转位涡出发,利用行波变换和约化摄动法导出了弱二次切变基本流下β变化和地形共同作用的正压Rossby孤立波振幅满足非齐次KdV方程.并计算了非齐次KdV方程的系数,说明弱二次切变基本气流、β变化和地形对Rossby孤立波的作用.     

正压大气模式下具有β效应与地形效应的Rossby孤立波

正压大气模式下,采用摄动方法和时空伸长变换推导了具有β效应、地形效应和耗散的mKdV-Burgers方程,得到Rossby孤立波振幅的演变满足带有β效应,地形与耗散的mKdV-Burgersm方程的结论.说明β效应、地形效应是诱导Rossby孤立波的重要因素.     

具有非线性地形的正压流体中孤立Rossby波的mKdV方程

正压流体中,采用摄动方法将准地转位涡方程推导出地形效应的mKdV方程,得到Rossby波振幅的演变满足地形效应的mKdV方程的结论,说明地形效应是诱导Rossby孤立波的重要因素.     

完整Coriolis力作用下的二维非线性Rossby波

本文在正压流体中,从包含完整Coriolis参数的准地转位涡方程出发,在弱非线性长波近似下,采用多时空尺度和摄动方法,推导出大气非线性Rossby波振幅演变满足带有地形强迫的非线性Zakharov-Kuznetsov(ZK)-Burgers方程.结果分析表明:地球旋转的水平分量、β效应、地形效应和耗散都是诱导二维Rossby波产生的重要因子.     

线性缓变下垫面和耗散共同作用的Rossby孤立波包

本文从正压流体的准地转位涡方程出发,考虑到Rossby波随时间、空间演变的多尺度特性,采用多重尺度和摄动展开的方法推导了在线性缓变下垫面和耗散共同作用下的非线性Rossby波包演变满足推广的非线性Schdinger方程,并得到单个包络的孤立波解.通过分析包络的孤立波解,指出在耗散与下垫面共同作用下,大气中会出现双曲正割形状的Rossby孤立波包.同时得到,在切变基本流存在的情况下,地形强迫和耗散对Rossby包络孤立波的传播速度、波数和频率均有影响的结论.     

关于完整Coriolis力和地形作用下非线性Rossby波的研究

从含有完整Coriolis力的地转位涡方程出发,采用合理的赤道β平面近似,利用摄动法和时空伸长变换,推导了具有地形和耗散共同作用下的非线性Rossby波演变规律,其振幅满足非齐次Benjamin-Davis-Ono-Burgers(BDO-Burgers)方程.分析说明了地球旋转水平分量和下垫面对Rossby波演变的影响.当取特殊情况时,本文的结论可以退化为前人的结果.     

地形作用下的近赤道非线性Rossby波

本文首次从带有地形的赤道大气基本方程组出发,利用浅水模式近似、半地转近似、Gardner-Morikawa变换以及摂动展开法得到了具有地形效应的赤道非线性波动振幅所满足的Korteweg-de Vries方程,并且利用Jacobi椭圆函数展开法求得非线性方程对应的周期波解和孤立波解,指出地形是产生赤道Rossby孤立波的重要因素.     

切变基本纬向流中非线性赤道Rossby长波

为了解决观测和理论研究中的一些问题以及更好地了解热带大气动力学 ,有必要进一步研究基本气流的变化对大气中赤道Rossby波动的影响 .本文研究分析基本气流对赤道Rossby长波的影响 ,利用一个简单赤道 β平面浅水模式和摄动法 ,研究纬向基本气流切变中非线性赤道Rossby波 ,推导出在切变基本纬向流中赤道Rossby长波振幅演变所满足的非线性KdV方程并得到其孤立波解 .分析表明 ,孤立波存在的必要条件是基本气流有切变 ,而且基流切变不能太强 ,否则将产生正压不稳定 .     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Information for authors

正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research.     

INTERNATIONAL RESEARCH AND TRAINING CENTER ON EROSION AND SEDIMENTATION(IRTCES)

正Director:Shangfu Kuang,China Vice-directors:Chunhong Hu,China Duihu Ning,China Guangquan Liu,China The International Research and Training Center on Erosion and Sedimentation(IRTCES)was jointly set up by the Government of China and UNESCO on July 21,1984.It aims at the promotion of international exchange of knowledge and cooperation in the studies of erosion and     

Calendar of events

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Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and