超级单体引发的龙卷天气过程分析

利用营口市多普勒天气雷达资料,对2005年8月10日16时10-20分左右营口市东南部六个乡出现的龙卷天气过程进行了简要分析,该龙卷发生前的主要天气形势是:一个东移的东北低涡引导高空槽,沿高空等高线冷干气流与低空的暖湿气流产生对流不稳定层结,超低空南支急流与低空西南风急流以及高空西北风产生的较大垂直风切变,有利于龙卷天气的产生.产生该龙卷的对流系统是由渤海湾生成的片状层状云和积状云混合降水回波.自东向偏北方向移动,15:50以后低层反射率因子的强降水回波移入大连北部与营口南部临近区域,在层状云降水中含有一些零散的和有组织的对流降水回波,主体为一个近似团状的对流系统,而龙卷产生自该系统南端的一个超级单体.最初的中气旋形成于8月10日15:56,相应对流单体的反射率因子还没有呈现出超级单体的特征,随后中气旋迅速发展加强,在16:02-16:08反射率因子形态呈现出经典超级单体的特征:明显的低层入流缺口,入流缺口位于超级单体移动方向(偏东南方向)的右侧,低层的弱回波区和中高层的回波悬垂结构,最大反射率因子超过56 dRz.在龙卷产生前几分钟和龙卷进行过程中,中气旋保持较强,而后迅速减弱,低层入流缺口渐渐消失.在龙卷进行过程中,相应45 dBz超级单体的反射率因子区局限在6 km以下,此系统为低质心的对流系统,产生的天气是龙卷,伴随有大风短时强降水,与冰雹的高质心对流系统有明显区别.同时也初步探讨了引发此次龙卷的生成机制.     

天线座水平度对目标定向影响的解析分析

本文定义了在天气雷达天线座水平度数值非0条件下的“实用坐标系”,并给出了该坐标系与“理想坐标系”之间的解析关系;在此基础上通过严格数学分析,给出了天气雷达探测目标的方位、仰角在“实用坐标系”中的读数与其在“理想坐标系”中对应的方位、仰角数值之间的多元函数关系;定义了方位误差分析函数、仰角误差分析函数,并利用所定义的误差分析函数对天气雷达天线座水平度数值如何影响目标定向进行了深入的解析分析。结果表明：仰角读数在45°以下,天线座水平度引起的方向定位误差不会大于天线座水平度自身的数值;当仰角读数大于45°后,天线座水平度引起的方向定位误差将迅速增大。尤其在接近天顶的空间区域,天线座水平度引起的方向定位误差可达天线座水平度数值本身的百倍以上。     

Using microwave links to adjust the radar rainfall field

The final stage in processing radar data so as to arrive at an estimated rain field typically involves a comparison of the preliminary radar-derived estimates of hourly rainfall with those observed by ground-based gauges. Often a mean field bias adjustment will then be applied using an age-weighted average of the individual gauge–radar comparisons. In this paper, a mean field bias adjustment is presented that uses the path-integrated rainfall estimates provided by microwave links together with information from gauges. It is shown to be at least as efficient as the current gauge-based procedure used by the UK Met Office to improve the accuracy of radar-based estimates of rainfall at the ground.     

中国天气发生器模拟非降水变量的效果评估

文中介绍了天气发生器BCC/RCG-WG基于谐波分析和多变量平稳过程对最高气温、最低气温、日照时数、相对湿度和平均风速等5个非降水变量的模拟模型,并根据中国669个站点1971-2000年的逐日气候资料(降水、最高气温,最低气温、日照时数、相对湿度和平均风速)计算了各站点的非降水变量的模拟参数.根据计算的模拟参数对中国...     

辽宁人工增雨示范区降水云系与降水量分析

统计分析了1980～1999年辽宁人工增雨示范区内5～10月各类降水云系产生不同强度降水的降水次数和降水量特征。结果表明:降水时长与其相对应的降水次数呈反比关系,降水时长越长,其相应的降水次数越少;而降水时长与其降水量的分布则呈不规则的波动;降水时长为2～8 h的降水量对总雨量的贡献为66%,是实施人工增雨作业的最佳时段。     

Cultural climatology and the representation of sky, atmosphere, weather and climate in selected art works of Constable, Monet and Eliasson

The visual turn presents new challenges and methodologies for the pursuit of geography as we seek to communicate our ideas and understanding within and beyond the discipline. This paper attempts to show the potential importance of visual culture within a field that we may call cultural climatology. Cultural climatology seeks to explore the dialectic between society and atmosphere, weather and climate at a variety of temporal and spatial scales. A new visual approach to cultural climatology is presented as a possible way of stimulating conversations across the divide between the social and physical sciences. Images and visualisation assert their presence in the understanding, modelling and communication of many nature/culture debates, highlighting a need both for visual literacy across geography, and for social and physical scientists to share their visual methodologies. Cultural climatologists, like other scientists, need visual methodologies for both the critical construction and deconstruction of the images they wish to present and with which they are confronted. To illustrate the importance of visual literacy for cultural climatologists this paper introduces a sample of works from three artists: Constable, Monet and Eliasson. It shows how an exploration of their work (via a theory of pictures) could help to provide: firstly a methodology for understanding the cultural symbolism of skies and weather; secondly an assessment of the urban atmosphere in London at the turn of the 20th century and thirdly an example of the effective representation of atmosphere, weather and climate involving public participation and understanding. Lessons learned from deconstructing these works of art will then be used to suggest improvements in the visualisation of weather in the production and consumption of weather forecasts (thus, picturing theory).     

沈阳天气预报业务自动化平台的开发研制

为了适应天气预报业务现代化、自动化发展的需要,应用VB,VF,VC,FORTRAN等多种语言,借助于Arcview地理信息系统及其空间分析模块、可视会商视频和9210工程等多项技术,开发研制了沈阳天气预报业务自动化平台,借以提高气象预报工作效率和质量。     

夏季南亚高压的演变及有关天气系统的响应研究

本文通过对6—7月份100 hPa南亚高压形态变化规律特征的描述和有关天气系统间的响应变化分析,总结了南亚高压进退振荡周期和南亚高压与副热带高压的响应关系,并进一步论证了南亚高压与江淮梅雨关系。根据所得结论对历史资料进行了反查验证。提出了有一定应用价值的代表性结论:(1)6—7月南亚高压东伸指数和南亚高压脊线变化呈波动状周期性北跳东进,其变化周期均在10—12 d左右,南亚高压开始北跳东进的时间、维持长度决定了我国东部梅雨始期和梅期长短,并具有很好的对应关系。(2)根据南亚高压脊线和副高脊线的线性关系,可采用110～120°E的平均南亚高压脊线位置≥28～30°N作为入梅的指标之一,利用110～120°E的平均南亚高压脊线位置≥32～35°N作为出梅的指标之一。这些结论的提出具有一定的理论意义,特别是利用南亚高压进行入、出梅的判别丰富了梅雨领域的研究,同时这些结论为中长期天气预报提供了新的思路和参考指标。     

云的垂直速度特征分析及人工影响天气作业措施探讨

利用2002年5—7月肥西风廓线仪资料结合常规地面观测资料,对出现各种云时的垂直速度特征进行了分析,在此基础上提出了人工影响天气作业的一些具体措施,希望对云的研究和人工影响天气作业提供帮助。     

Weather routing for offshore transportation using genetic algorithm

Conventional weather routing is defined as determining the optimum route for a merchant ship such that distance or duration of the voyage and fuel consumption are minimized. If the purpose of a voyage is offshore transfer, the term “optimum” includes aspects of operational safety such as towing tension and six-degree motion response of tow. This paper presents the development of a weather routing method for determining the optimal route, which is defined here as the route with minimum average towing tension with a restricted time of arrival and significant motion response. A genetic algorithm is applied to solve optimization problems. Optimized routes of this research have an advantage in towing tension and satisfy motion constraints. The result of this study can contribute to safe and effective planning for offshore transport.