2017年湖南一次极端降雨过程特征及成因分析     

许霖  姚蓉  陈红专  苏涛  周莉 《沙漠与绿洲气象(新疆气象)》2020,14(1):31-38

2017年6月22日-7月2日湖南出现了一次罕见的大范围持续暴雨、大暴雨过程，持续强降雨造成了重大人员伤亡和财产损失。本文利用地面常规探测资料、自动站资料和NCEP/NCAR再分析资料，对此次极端降雨过程的成因进行了分析。结果表明：（1）过程发生在单阻型稳定背景条件下，西太平洋副高较常年位置偏南，带状副高与北方冷涡对峙，导致了梅雨锋雨带在湖南摆动；（2）高低空急流加强了低层辐合高空辐散的动力作用，同时高能高湿激发了对流不稳定的产生，为大暴雨产生提供了动、热力条件；（3）水汽异常偏高，整层可降水量超过常年同期1-2个标准差，其大值区的演变与实际强降水区域对应较好；（4）湖南地形对降水有一定的增幅作用，地形坡度绝对值与降水量变化十分吻合，地形变化越剧烈降水强度越大，且在地形复杂的2个山峰之间区域通常对应着降水的峰值。  相似文献   

北京两次重污染沙尘天气成因及动力传输特征的对比研究     

王华  轩春怡  吴方  金晨曦  李梓铭  李靖  郭金兰 《沙漠与绿洲气象(新疆气象)》2020,14(4):18-26

应用气象、空气质量和ERA-Interim再分析资料,结合HYSPLIT后向轨迹模型和地理信息,对比分析了2018年北京两次重污染沙尘天气的成因、传输特征及影响要素等。结果表明:两次过程的沙尘源地均为蒙古国,但3月28日沙尘天气由蒙古气旋引发,传输出现折向,以东北和偏东两条路径输送入京,5月28日沙尘受低涡和发展的低压冷锋影响,为典型的西北传输路径;高空的引导气流与低层冷空气的强度以及地形是导致沙尘传输出现显著差异的主要影响因素;高空为偏西气流,低层冷平流较弱,受到山脉的阻挡,沙尘气团东移至地势较低的区域后,在气压梯度力的驱动下传输方向发生转折,以偏东路径绕流进入北京;高空的偏北气流和低层冷平流较强,沙尘气团可直接翻越山脉从西北路径入京,沙尘粒子的运移高度相对较高。  相似文献   

The Vertical Transport of Air Pollutants by Convective Clouds. Part I: A Non-Reactive Cloud Transport Model   总被引：1，自引：0，他引：1  

Kong Fanyou  Qin Yu 《大气科学进展》1993,10(4):415-427

A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and a numerical experiment is completed to simulate the vertical transport of ground-borne, inert gaseous pollutant by deepthunderstorm. The simulation shows that deep convective storm can very effectively transport high concentrated pollutant gas from PBL upward to the upper troposphere in 30 to 40 minutes, where the pollutant spreads laterally outward with strong anvil outflow, forming an extensive high concentration area. Meanwhile, relatively low concentration areas are formed in PBL both below and beside the cloud, mainly caused by dynamic pumping effect and sub-cloud downdraft flow. About 80% of the pollutant gas transported to the upper troposphere is from the layer below 1.5 km AGL (above ground level).  相似文献   

N-DP新型数据回放仪的研制     

张焕生  马云生 《地震地磁观测与研究》1993,(3)

主要介绍N-DP新型数据回放仪的研制思路、结构、特点及应用情况。  相似文献   

Two-dimensional transport of dust from an infinite line source at ground level: non-zero roughness height   总被引：1，自引：0，他引：1  

M. H. A. Hassan  I. A. Eltayeb 《Geophysical Journal International》1993,115(1):211-214

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夏季华南降水与水汽输送气流及大气加热场的关系     

唐东升  刘文泉 《南京气象学院学报》1994,17(2):148-152

利用ＣＥＭＷＦ／ＷＭＯ逐日资料分析了１９８２年夏季大尺度水汽输送气流，大气加热场与华南降水的关系。结果表明，来自印度洋，孟加拉湾和西太平洋的两支水汽输送气流都具有３０－６０天振荡特征，并共同影响华南地区的降水；夏季风建立后，华南强降水过程与其上空的加热场有良好的对应关系；视热源与水汽汇的加强（减弱）对应华南地区多（少）雨期。  相似文献   

The vertical transport of air pollutants by convective clouds Part II: Transport of soluble gases and sensitivity tests     

Kong Fanyou 《大气科学进展》1994,11(1):1-12

A two-dimensional, non-reactive convective cloud transport model is used to simulate in detail the vertical transport and wet scavenging of soluble pollutant gases by a deep thunderstorm system, Simulations show that for gases with not very high solubility, a deep and intense thunderstorm can still rapidly and efficiently transport them from boundary layer (PBL) up to mid and upper troposphere, resulting in a local significant increase of concentration in the upper layer and a reduction in PBL. Dissolution effects decrease both the incloud gas concentration and the upward net fluxes. The higher the solubility is, the more remarkable the decrease is. However, for very low soluble gases (H < 102 M atm-1), the influences are very slight. In addition, the effects of irreversible dissolution and aqueous reactions in drops on the vertical transport of gaseous pollutants are estimated in extreme.  相似文献   

Groundwater contaminant transport including adsorption and first order decay     

Jaco J. A. van Kooten 《Stochastic Hydrology and Hydraulics》1994,8(3):185-205

This study deals with the transport of a contaminant in groundwater. The contaminant is subject to first order decay or linear adsorption. Its displacement can be modeled by a random walk process in which particles are killed at exponentially distributed times. Dirichlet problems are derived for the rate and mean time at which contaminated particles reach a particular part of the boundary of a certain domain. These Dirichlet problems are solved asymptotically for two types of 2D-flow patterns: flow parallel to the boundary of a domain and arbitrary flow towards a well in an aquifer.  相似文献   

空间运输联系的生成与增长规律研究   总被引：29，自引：2，他引：29  

张文尝  唐秀芳 《地理学报》1994,49(5):440-448

空间运输联系是指在自然、社会、经济诸要素综合作用下，区域间通过交通运输设施进行旅客和货物的交流。区域差异与互补是空间运输联系产生的直接原因，交通设施是空间运输联系实现的基础。本文以世界不同类型国家和我国近半个世纪的运输活动及其社会经济背景值作为研究对象，采用定量与定性相结合的实证分析方法，经过归纳、演绎和推理，深入研究了运输联系生成的内在机制和增长演变的趋势，得出了旅客生成密度和客运强度随经济增长而增长、货物生成密度和货运强度随经济增长而降低的结论。在评价指标方面，提出了生成密度、运输强度等概念和指标，并对世界主要国家的运输发展进行了对比分析。  相似文献   

The Phononic Lattice Solid By Interpolation For Modelling P Waves In Heterogeneous Media     

Lian-Jie Huang  Peter Mora 《Geophysical Journal International》1994,119(3):766-778

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