双台风相互作用及其影响

采用三维变分混合同化方法对双台风菲特（1323）和丹娜丝（1324）、天鹅（0907）和莫拉克（0908）进行数值模拟,并在此基础上,采用移除双台风中任一台风和增强或减弱任一台风的方法,对双台风的相互作用进行了敏感性试验。结果表明:台风丹娜丝的作用导致台风菲特路径偏南,移速偏慢;台风菲特的作用导致台风丹娜丝路径偏北,移速变化不大。双台风相互作用使台风菲特和丹娜丝强度发生变化。在台风菲特强盛阶段强度更强,减弱消亡阶段强度更弱。2013年10月6-9日我国华东地区出现的强降水主要受台风菲特影响,台风丹娜丝使降水强度增强、强降水中心位置偏南。双台风相互作用使台风天鹅移向偏南,移速偏快,但台风天鹅对台风莫拉克的移向、移速影响不大;台风天鹅路径盘旋曲折,每次移向的变化都与台风莫拉克有关;台风天鹅打转程度与台风莫拉克的强度呈正相关,双台风间存在涡度、水汽通量等的相互影响及输送机制。     

台风"烟花"缓慢移动的机理研究:远距离双台风相互作用

本文通过一系列敏感性试验探究台风"烟花"移动缓慢的可能机理。结果表明:台风"烟花"的移动对台风"尼伯特"的强度较为敏感。"尼伯特"强度主要通过影响其附近大尺度低压系统的强度与范围,间接影响"烟花"的大尺度引导气流,进而影响"烟花"的移动。具体而言,"尼伯特"与其附近大尺度低压系统环流共同激发西北风引导气流,抵消了部分副高西南侧的东南风引导气流,从而造成"烟花"受到的大尺度引导气流偏弱,致使其移动缓慢,路径复杂。此外,当"尼伯特"强度越大时,以上过程对"烟花"移动的影响也越大。因此,当两个台风相距较远时,双台风相互作用可能通过影响周围的大尺度系统,间接对台风路径产生较大影响。     

双台风相互作用的数值研究

无基本气流的情况下，应用无辐散正压模式对初始呈西北-东南等方位的双台风相互作用进行数值研究，探讨了非对称理论在双台风相互作用中的应用。试验结果表明：双台风的运动特征能够运用非对称理论进行解释；非对称流函数场中，通风气流分别控制着双台风的移动，同时双台风的移动对其对应的非对称结构具有反作用。试验还表明，台风非对称结构内小尺度涡旋的强度及其绕台风中心逆时针旋转的快慢与台风路径的摆动关系密切：模式可以模拟出台风逆时针打转、“蛇形”摆动等异常移动路径。     

不同尺度涡旋相互作用对台风的结构和移动的影响

根据大气运动原始方程组导出一个支配台风中心移动的基本方程，方程中包括了非绝热加热，温度场分布，地形与摩擦等各中能影响台风移动的强迫因子。对非绝热加热与水平温度分布的使用所作分析表明，非轴对称的非绝热引导作用可使台风加速、减速或转向运动；温度场上的准区对台风有吸收作用。     

一个β中涡对双台风相互作用影响的物理过程

利用高分辨率f平面正压拟谱模式,分析一个β中尺度涡对双台风相互作用影响的物理过程。结果表明：β中涡的存在可以使原本排斥的两个DeMaria型台风涡旋合并;β中涡改变双台风相互作用终态的物理机制是：初始时段处于某一台风涡旋正影响区内的β中涡,构成了非对称涡度场,进而在该台风涡旋内部产生指向另一个台风涡旋的气流。该气流如果足够强,则会使两个台风的中心距离在短时间内下降到合并临界距离之内,触发双涡合并过程的发生。     

海气相互作用对台风结构的影响

利用前期工作中耦合试验和未耦合试验对台风Krovanh(2003年)数值模拟的结果,分析了海-气相互作用对台风结构的影响。结果表明,台风引起的海面降温大大降低了海洋向大气输送的潜热通量,同时使得感热通量向下传递到海洋。另一方面,台风引起的海表面温度(SST)降低,反馈到台风使其结构轴不对称性加强,且在中高层尤为显著。分析了台风对称结构的基本特征。     

双台风相互作用的一种分析

一、引言 台风移动主要受背景流场的“引导气流”操纵。当间距足够近的两个或多个台风同时存在时,由于台风的位置变化比较显著,由它们引起的那部份“引导气流”的变化也就较大,这就使得在多台风情况下台风路径比较复杂。 在我们的统计动力学方案中,虽然在选取样本时已经有意识地剔除了一些影响明显的双台风个例。但是,从拟合误差的初步分析中,仍然很清楚地看出,产生较大误差极     

关于双台风相互作用的初步分析

本文应用1961—78年西北大平洋30对双台风资料,分析了双台风互旋与双台风中心间距、强度及相互方位的关系,并应用天气学方法计算和分析了单纯的双台风互旋与环境流场引导气流的作用,指出在双台风形势下,环境流场的引导作用是重要的。     

海表温度对台风移动的影响

运用１９９０－１９９１年西北太平洋上气象卫星的高分辨率ＳＳＴ，天然图和台风路径图，分析了１７个台风移动与ＳＳＴ的关系，发现它们相关密切，即在无较强天然系统引导的情况下，台风沿着前期ＳＳＴ暖区外围的等ＳＳＴ线并与暖轴平行或者沿着暖轴移动，同时避开行进前方的冷ＳＳＴ区。对西行，西北移，北上和抛物线型４种常见台风路径，选取了５个有代表性的台风和相应的ＳＳＴ场，分别较     

潮湿空气对台风移动的影响

引言 谢义炳教授提出空气湿度对大气运动有重要影响,并指出台风移动应当以能量传播观点来代替。我们认为这一观点对台风移动的预报是有实践意义的。本文采用分析等压面图上湿热能量场的方法,试图探讨湿空气对台风移动的影响。     

A study on the relationship between the rotation of binary typhoons and steering current

Many studies show that, within a certain distance (ca. 700–800 n mi), two typhoons forming a binary typhoon (BT) system would rotate as a whole and attract each other, which is known as “Fuji-whara Effect” (FE). This paper indicates that only 30.3% of BTs has experienced remarkable cyclonic rotation with a 12-hr angle ≥+10° when two components are less than 20° lat apart, and that the probability is much higher with the eastern component in the NE than in the SE quadrant for the western one, implying the steering effect of the environmental flow field (EFF) on them. 47 observations from 13 BTs are separately used for calculating the angular velocity due to FE and EFF and the results are compared. The conclusion can be stated as follows: FE is dominant with the centers of two elements below 7° lat apart; the EFF steering current plays a major role when they are in the range of 7–15° and for a distance above 15° the principle of FE holds no longer.     

Effect of the Interaction of Different Scale Vortices on the Structure and Motion of Typhoons

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登陆热带气旋暴雨突然增幅和特大暴雨之研究进展

采用1950—2015年在浙南闽北登陆的台风历史个例及其降水资料,将台风路径分为西行类和北上类来探讨浙江省受不同路径台风影响时,发生区域性暴雨增幅或不发生增幅的形势场和物理量场特征及台风暴雨增幅落区规律。结果表明：台风登陆西行和北上路径发生区域性暴雨增幅或不发生暴雨增幅环境场特征均有明显的差异,增幅型台风登陆前后对流层中低层建立从南海、台湾东部到浙江沿海并伸入浙江内陆的E-SE急流和水汽通道,θ_se平流呈东暖西冷的结构,台风中心呈高层辐散、低层辐合的结构;若有弱冷空气入侵,暴雨增幅强度更强、范围更大,暴雨增幅落区明显向浙中北部地区伸展。无暴雨增幅型台风对流层中低层从南海到台湾没有明显的偏南风急流,中低层浙江沿海的SE风急流轴及水汽通道偏北偏东,强度偏弱,没有伸入浙江内陆;浙江处于大陆暖气团的SE侧,浙江沿海无明显的暖平流;高层无辐散或弱辐散、低层弱辐合。

     

The interaction of binary vortices in a barotropic model

Summary The interaction of binary cyclonic vortices is investigated using the nondivergent barotropic model of Chan and Williams (1987) under two situations: a quiescent environment and a linearly-sheared background flow. It is found that the mutual interaction between the vortices results from a combination of two processes: the advection of symmetric vorticity by the asymmetric flow and the advection of asymmetric vorticity by the symmetric flow. The latter contribution is rather significant. Whether the vortices in a binary system attract or repel each other depends on the asymmetric vorticity distribution associated with the two vortices. Such a distribution is governed by the structure (size) of and the separation between the vortices. In the presence of a sheared flow, the contribution from the advection of asymmetric vorticity by the symmetric flow may also become appreciable depending on the structure and magnitude of the shear. Furthermore, the geographical locations of the vortices in relation to the sheared flow are also important in determining the relative movement of the vortices.In the presence of , the movements of the vortices are modified by the northwestward -drift However, the relative motion between the vortices is almost identical to that on an f-plane. In other words, the mutual interaction between the vortices is largely independent of . Alternatively, the two vortices can be considered to be one system which drifts towards the northwest under the influence of while they interact with each other within the system. Physically, this independence arises because the two relative vorticity advection terms have much larger magnitudes than the planetary vorticity advection term. However, the -effect is still important in that it modifies the asymmetric flow associated with each vortex and hence the asymmetric vorticity. Such modifications change the advection patterns compared with the =0 case and hence lead to different vortex movements. The presence of a linear shear causes the binary system to move as if it was a large (for a cyclonic shear) or smaller (for an anticyclonic shear) vortex under the influence of .With 22 Figures     

两次台风的雷达回波特征及其与路径的关系

一、两次台风的共性 7514号台风降水回波呈现极其典型的同心双层眼壁结构。图la是一张衰减30分贝的照片,它与6903号特强台风7月28日00时16分的照片(见图1b)十分相似。这种同心双层眼壁结构是比较少见的,内眼壁结构都呈“6”字形,内眼区直径都在15—20公里左右,外眼壁结构都呈准圆形,外眼区直径分别为90和120公里,里层螺旋雨带和台风     

Long-term variations in the frequency of typhoons and their connection with various formation factors

Variations in the frequency of tropical cyclones in the Northwest Pacific in 1961-2015 and their connection with various factors are analyzed. The examined factors are the occurrence rates of the certain patterns of atmospheric circulation (according to the Vangengeim-Girs classification) in the Pacific-American sector, sea surface temperature in the North Pacific, and the position of the North Pacific High center. Steady relationships between these parameters are revealed.     

散射计和下投式探空仪资料对台风模拟的影响

为了评估同化QuikSCAT海平面气压场资料和Dropsonde资料对台风"Bilis"和"Kat-rina"模拟的影响,通过WRF-3DVAR变分同化系统将QuikSCAT海平面气压场资料和Dropsonde资料同化到WRF模式中,并以未同化任何资料和同化了QuikSCAT海平面气压场以及同化了Drop-sonde资料的数据为初始场,应用WRF模式进行模拟预报,并对得到的初始分析场和模拟预报得到的结果与台风实况报文进行了对比,得到的结论是:对台风初始时刻海平面气压场分布、初始台风中心定位、台风初始暖心结构的改善、台风路径、海平面最低气压场、海面最大风速和雷达回波的模拟方面,同化QuikSCAT海平面气压场的效果比同化Dropsonde资料明显,其中二者对海平面最低气压场的改进效果比海面最大风速的要好。但是两种资料的同化对初始相对湿度和台风强度细节变化方面都没有产生明显改善作用。同化QuikSCAT海平面气压场试验虽然仅仅同化了单层海平面气压场,但是在三维变分同化系统的动力约束作用下,也可以影响到中高层的各个要素场。     

The influence of convergence movement on turbulent transportation in the atmospheric boundary layer

Classical turbulent K closure theory of the atmospheric boundary layer assumes that the vertical turbulent transport flux of any macroscopic quantity is equivalent to that quantity‘s vertical gradient transport flux. But a cross coupling between the thermodynamic processes and the dynamic processes in the atmospheric system is demonstrated based on the Curier-Prigogine principle of cross coupling of linear thermodynamics. The vertical turbulent transportation of energy and substance in the atmospheric boundary layer is related not only to their macroscopic gradient but also to the convergence and the di-vergence movement. The transportation of the convergence or divergence movement is important for the atmospheric boundary layer of the heterogeneous underlying surface and the convection boundary layer.Based on this, the turbulent transportation in the atmospheric boundary layer, the energy budget of the heterogeneous underlying surface and the convection boundary layer, and the boundary layer parameteri-zation of land surface processes over the heterogeneous underlying surface are studied. This research offers clues not only for establishing the atmospheric boundary layer theory about the heterogeneous underlying surface, but also for overcoming the difficulties encountered recently in the application of the atmospheric boundary layer theory.