The South China Quasi-Stationary Front During the Ice-Snow Disaster of January 2008

South China suffered an extremely severe disaster caused by low-temperature and ice-snow during the last 20 days of January 2008. The freezing rain and snow are climatologically related to the South China quasistationary front (SCQSF) in mid winter. The three-dimensional structure of the SCQSF was examined based on the weather charts, the sounding proˉles, and the vertical cross-sections using the method of classical synoptic analysis.     

A New Typhoon Bogus Data Assimilation and its Sampling Method: A Case Study

In this study,the authors introduce a new bogus data assimilation method based on the dimension-reduced projection 4-DVar,which can resolve the cost function directly in low-dimensional space.The authors also try a new method to improve the quality of samples,which are the base of dimension-reduced space projection bogus data assimilation (DRP-BDA).By running a number of numerical weather models with different model parameterization combinations on the typhoon Sinlaku,the authors obtained two groups of samples with different spreads and similarities.After DRP-BDA,the results show that,compared with the control runs,the simulated typhoon center pressure can be deepened by more than 20 hPa to 30 hPa and that the intensity can last as long as 60 hours.The mean track error is improved after DRP-BDA,and the structure of the typhoon is also improved.The wind near the typhoon center is enhanced dramatically,while the warm core is moderate.     

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Aircraft Measurements of Cloud–Aerosol Interaction over East Inner Mongolia

To investigate the potential effects of aerosols on the microphysical properties of warm clouds, airborne observational data collected from 2009 to 2011 in Tongliao, Inner Mongolia, China, were statistically analyzed in this study. The results demonstrated that the vertical distribution of the aerosol number concentration(N_a) was similar to that of the clean rural continent. The average aerosol effective diameter(D_e) was maintained at approximately 0.4 μm at all levels. The data obtained during cloud penetrations showed that there was a progressive increase in the cloud droplet concentration(N_c) and liquid water content(LWC) from outside to inside the clouds, while the Nawas negatively related to the Ncand LWC at the same height. The fluctuation of the N_a, Ncand LWC during cloud penetration was more obvious under polluted conditions(Type 1) than under clean conditions(Type 2). Moreover, the wet scavenging of cloud droplets had a significant impact on the accumulation mode of aerosols, especially on particles with diameters less than 0.4 μm. The minimum wet scavenging coefficient within the cloud was close to 0.02 under Type 1 conditions, while it increased to 0.1 under Type 2 conditions,which proved that the cloud wet scavenging effect under Type 1 conditions was stronger than that under Type 2 conditions.Additionally, cloud droplet spectra under Type 1 conditions were narrower, and their horizontal distributions were more homogeneous than those under Type 2 conditions.     

气象多普勒雷达测试技术介绍

本文主要通过详细的图示和相关的计算公式,以DW SR 2500C/K为例,介绍了进口多普勒气象雷达的测试和计算,其中包括脉冲宽度、发射频率、脉冲重复频率、峰值功率、接收机信号线性性和动态范围和最小可探测信号的测量等。对于国产气象多普勒雷达的测试从原理和方法上具有参考和充实作用,有普遍的实用价值。     

高层大气温度和高度场异常对我国地面气温和降水的影响

用SVD方法分析了NCEP／NCAR 1958—1997年再分析资料中月平均的300hPa温度(下称“高层温度”)和100hPa高度(下称“高层高度”)距平场与中国160个测站的月平均地表气温(下称“我国温度”)和月降水距平场的时滞和空间耦合关系,讨论了高层温度和高度距平场的空间分布和时间演变对我国气温和降水异常的影响。结果表明,高层温度和高度距平场的整体空间分布形势对中国气温和降水的影响明显,不同关键区的高层温度和高度距平场对我国不同区域的气温和降水异常有影响,具有明显的区域耦合特征。伊朗高原和青藏高原及其以南的热带低纬地区是高层温度和高度场的关键区。高层温度场对我国气温场和降水场的影响主要表现为年际变化,而高层高度场的影响主要表现为年代际变化。我国长江和黄河流域、华南和江南地区是受高层温度场和高度场异常影响最明显的地区。     

江淮以南地区暴雨和强降水的中尺度天气动力学研究进展

经过新中国成立以来多次中尺度天气试验研究,江淮以南地区暴雨和强降水的中尺度天气动力学研究取得长足进展。其进展主要体现在两个方面:一是用较高分辨率的观测资料(包括地面和高空探测的加密观测以及卫星和雷达的观测)对形成暴雨和强降水的中尺度天气系统的结构特征和生命史过程建立了天气学概念模型,特别是对暴雨和强降水有重要影响的α中尺度和β中尺度对流系统,建立了观测个例的中尺度物理模型;二是探索了暴雨和强降水的动力学和热力学的物理机制,为精细化数值模式的设计提供了理论支撑,为灾害性天气预测预警提供了技术支持。本文在以往暴雨和强降水研究的基础上,着重对暴雨和强降水的中尺度天气科学试验、江淮以南地区暴雨和强降水发生主要区域的中尺度天气动力学研究进行了概述。     

分布式开放型多普勒天气雷达产品系统设计

随着我国多普勒天气雷达网建设的深入发展, 雷达气象产品系统开发和资料应用越来越迫切。文章介绍了开放软件系统模型, 分析了新一代天气雷达特点和发展需求。结合新一代天气雷达网和我国气象业务网发展状况, 提出和研究了可供新一代天气雷达使用的开放系统的分布式业务模式, 研究和设计了雷达气象产品开放系统的结构和运行方式。文中的分布式开放型雷达产品系统的结构和模型, 对其他类业务和科研系统的开发和发展具有参考价值。