【作者】 周毓荃；

【导师】 孙照渤； 胡志晋；

【作者基本信息】 南京气象学院 ， 大气科学， 2004， 博士

【摘要】 本研究主要针对我国春秋干旱季节系统性层状降水云系的多尺度结构特征、人工增雨潜力条件及其增雨开发技术开展研究。以地处中原、具有典型代表意义的河南层状降水云系为主要研究对象，在对该地历史天气气候和云物理等资料分析的基础上，研究设计云系多尺度观测方案(包括加密观测项目、观测时空分辨率)，实施有设计的外场综合观测，获取云系结构多尺度(大、中、小、微)配套的实时观测资料；通过对各种观测资料的分项和综合处理分析，以典型个例观测和数值模拟分析研究为重点，综合多个例分析，研究河南层状降水云系多尺度宏微观结构特征、降水物理机制和人工增雨潜力条件，建立典型层状云系人工增雨概念模型，研究科学的人工增雨作业技术系统。为提高该类云系降水精细预报能力和人工增雨的科技水平，提供科学依据和技术支持。 取得的主要研究结果： 1．层状云系中—微尺度探测和分析处理技术方法。以加密观测的多普勒雷达、3小时探空、10～30分钟雨强、地面雨滴谱等间隔取样及在GPS引导下的飞机云物理探测等获取的三维高时空密度的综合探测为主体；配合专项设计开发的多路通讯采集存贮系统、多类信息的分析处理平台、主要观测项目的分析反演软件，结合多尺度云系模式，综合构成层状云系中微尺度探测和分析处理技术方法。 2．河南春秋季云水资源条件和云雨宏观物理特征。河南春秋季较丰沛的空中水资源主要集中在700hpa以下，其中地面—850hpa水汽占整层30％—45％。；降水天气的主要水汽输送路径有三条，以来自孟加拉湾的西南水汽输送带对降水最为有利；云系以冷暖混合云体为主，具有发生“播撒-供应”机制有利的宏观云体条件；云系降水的时段和面积一般只有云系生命期和面积的一半。总体上，河南春秋季具备较有利的人工增加降水的天气气候和云水资源条件。 3．河南层状云系多尺度结构特征和降水物理机制。造成河南春秋季层状降水云系的主要天气系统有低槽冷锋和地面气旋两大类。在大尺度冷锋气旋天气系统中，嵌有不均匀的中小尺度湿热力动力结构。表现为低层大尺度冷垫、中空不断出现的中尺度“冷涌”及对应的位势不稳定区。这些不稳定区是低层水汽输送摘要重要的动力条件，也是“播撒一供应”机制发生的有利的湿热力环境条件，云系较强降水回波在这里得到发展，使整体均匀的冷锋层状云系降水场有较强回波带和对流泡发展，带来地面有>10mmlh较强降雨中心产生和移动。冷锋云系中水凝物空间分布不均匀，云水含量丰沛的云水大值区在云体的中上部，其值为0.1(g/in3)。降水主要以冷雨过程发动，地面降水形成的微物理过程分别为低层暖云过程产生并通过碰并云水增长、降落到暖区的冰相粒子融化和融化的冰相粒子在云的暖区收集云水继续长大等三部分组成。 4.河南人工增雨有利条件及多尺度人工增雨概念模型。河南春秋季最有利人工增雨的天气条件结构是:中高空低槽、地面北路或东路冷锋构成的以锋后降水为主的低槽冷锋天气结构;符合一定条件的中小尺度湿热力动力结构是人工增雨有利的中尺度湿热力环境条件;在有利的中尺度湿动力条件下发展的冷锋宽层状混合回波带，且垂直剖面为冷暖混合体的“播撒一供应”结构配置合理的回波结构最有利;有利于人工增雨的冷锋云系云状为As和Sc，其下部为丰水区，对降水的增长起供水作用;冷锋云系中悬浮在中空O℃左右的云水团，有2一3小时的生命期，空间范围有20一100腼不等，是人工播云催化的有利条件;云中云水和冰晶的组合配置结构十分重要，满足云粒浓度>20/cm3(FSSP测)、冰晶浓度小于20/L(ZD一C测)的为最佳催化潜力区。 有利于“催化一供应”机制发生发展的中小尺度湿热动力环境条件和回波结构、及云中冰晶浓度、水汽含量和过冷云水含量的合理配置，共同构成了实施人工播云增雨的中尺度和微物理条件。 5.人工增雨作业技术系统。根据河南层状云多尺度时空结构特征和人工增雨条件，提出分时段监测、通信和分析处理平台的设计及多任务人工影响天气五段业务流程。并根据河南情况进行了部分开发，初步形成有充分科学依据、流程合理的层状云系飞机人工增雨作业技术系统。更多还原

【Abstract】 This work aims at studying multi-scale structures of large-scale stratiform precipitating clouds typical of Henan Province of central-eastern China in spring and autumn drought periods of China, the potentials and techniques of artificial rain increase. Through analysis of historical weather/climate and cloud physical data, developed are a number of multi-scale observational schemes including intensive observational items, and space/time resolutions of data for integrative field observations to obtain real-time measurements of the structures at large-, medium-, small- and micro-scale. From analysis of observed separate items, their integrative treatment and numerical simulation we place focus on case studies and their integration in investigating such structures of stratiform precipitating clouds over the target region, rainfall physical mechanisms and exploitation of artificial rainfall increase potentials, whereupon a conceptual model is constructed and a range of catalysis schemes are proposed to improve smaller-scale forecasting accracy and techniques for the rainfall increase, with the dominant results given below.1) The meso - micro-scale soundings and the data processing techniques. Three-dimensional high-density space/time soundings serve as the main body of data consisting of 3-hr interval Doppler probings, 10-30 min rainfall intensity, surface raindrop sizes sampling and GPS-guided flight cloud physics detections with output taken at 2-sec and 200-m intervals. And specific systems associated therewith are developed for multiple-way communication and data collection and storage, a platform for analysis, retrieval softwares for dominant items and multi-scale cloud models - all constitute a system of techniques for meso to microscale observations and analysis.2) Atmospheric water resource and macroscopic rainfall properties in dry periods of spring and autumn of the target region. These seasons are marked by richer atmospheric water mainly below 700 hPa, with 30 - 45% moisture concentrated below 850 hPa. Three passages of vapor transfer are related to the regional precipitation, especially the one carrying water from the Bay of Bengal. Mixed cold and warm cloud portions are favorable for ’catalysis - water supply’. The duration and rainfall-hit area are about half the lifecycle and rainbelt size, respectively. On the whole, the atmospheric conditions are favorable for artificial rain increase.3) Multi-scale strtiform cloud structures and precipitating mechanism. Atmospheric systems responsible for stratiform precipitating clouds in Henan during spring and autumn are low pressure ?cold front, and surface cyclone. Embedded in a large-scale cold front - cyclone are often meso-and small-scale wet thermal/dynamic structures that are uneven, with a huge cold "cushion" at low levels, frequent meso cold surges and related potentially unstable zones at middle levels. And such zones act as an important dynamic condition for low-level water transfer and also a favorable environmental condition for "seeding - water supply". There stronger echoes are detected, meaning that bubble convection develops in the precipitating fields of the clouds that are homogeneous in the main, causing centers of > 10 mm/hr surface rainfall to occur and migrate. The condensates distributed in such clouds are heterogeneous, with high-value cloud water bands located in the midto upper portions, reaching 0.1 g/m3. Rainfall is started mainly in cold portions. Microphysics for ground rainfall consists of low-level warm portions in which precipitating particles are produced, growing through collision with cloud water and when descending into the warm portions below, ice-phase particles melt and continue to grow by collecting cloud water there. 4). Favorable conditions of artificial rain increase and conceptual models for multi-scale rainfall in the study province. The optimal synoptic conditions are mid - high-level trough and a system of trough - cold front with rainfall occurring largely at the rear of the front moving f更多还原