Parameterizations of different hydrometeor spectral relative dispersion in the convective clouds

Spectral relative dispersion of different hydrometeors is vital to accurately describe sedimentation. Here, the Weather Research and Forecasting model with spectral bin microphysics is used to simulate convective clouds in Shouxian of Anhui province in China to study the spectral relative dispersion of different hydrometeors. Firstly, regardless of clean or polluted conditions, the relative dispersion of ice crystal spectra and its volume-mean diameter are negatively correlated, while the relative dispersion of other hydrometeor spectra is positively related to their respective volume-mean diameter. The correlations for cloud droplets and raindrops are affected by the process of collision–coalescence; the correlations for ice crystals, graupel particles, and snow particles could be affected by the deposition, riming, and aggregation processes, respectively. Secondly, relative dispersion parameterizations are developed based on a comprehensive consideration of the relationships between the relative dispersion and volume-mean diameter under both polluted and clean conditions. Finally, the relative dispersion parameterizations are applied to terminal velocity parameterizations. The results show that for cloud droplets, ice crystals, graupel particles, and snow particles, assuming the shape parameter in the Gamma distribution is equal to 0 underestimates the shape parameter and overestimates the relative dispersion; and for raindrops, assuming the shape parameter is equal to 0 is close to the relative dispersion parameterizations. The most appropriate constant shape parameters are recommended for different hydrometeors. The relative dispersion parameterizations developed here shed new light for further optimizing the terminal velocity parameterizations in models.摘要离散度的诊断对模式中沉降过程的准确描述至关重要. 本文利用WRF模式结合谱分档方案模拟安徽寿县地区的对流云, 研究不同水成物的离散度. 首先, 无论在清洁还是污染条件下, 除冰晶谱的离散度与体积平均直径间呈现负相关关系外, 云滴, 雨滴, 霰粒子与雪粒子谱离散度与体积平均直径呈现正相关关系; 云滴和雨滴受碰并过程影响, 冰晶, 霰粒子和雪粒子分别受凝华过程, 淞附过程和聚并增长影响. 其次, 综合考虑污染与清洁条件下离散度和体积平均直径之间的相关关系, 建立了离散度的参数化方案. 最后, 把该离散度方案应用到下落末速度的参数化方案中, 结果表明, 对于云滴, 冰晶, 霰粒子和雪粒子, 在Gamma分布中假设谱形参数等于0会低估谱形参数而高估离散度. 对于雨滴而言, 假设谱形参数等于0与参数化方案结果接近. 针对不同的水成物, 给出了最合适的谱形参数定值. 本文发展的离散度方案为进一步优化模式中下落末速度参数化方案提供参考.     

Estimation of actual evapotranspiration in the Nagqu river basin of the Tibetan Plateau

Theoretical and Applied Climatology - As a critical component of the energy and water cycle, terrestrial actual evapotranspiration (ET) can be influenced by many factors. This study was mainly...     

Response Process of Oceanto AtmosphericForcing and Optimal Response Frequency in the CZ Ocean Model

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20马力玻璃钢渔船的总体设计

作者为开发新型渔船并改善其性能和节约木材,设计了20马力玻璃钢渔船。船体总长Loa=13.65米,船宽B=3.40米,型深D=1.15米,平均吃水T_m=0.82米,航速V=6.5节,满载排水量为17.19吨,自持力为10天。全船采用玻璃钢材料,并设计成折角线形横剖面、延伸甲板和收缩形舭龙骨。本船稳性满足规范要求。横摇性能及适航性能良好。     

控制好细节就控制了质量--岩土工程勘察单位质量管理

该文根据岩土工程勘察管理的体会，提出要保证岩土工程勘察的质量，需加强各过程中的细节控制；并提出“控制好细节，就控制了质量”的观点。     

浅谈地下水超采的防治对策

地下水的超采已是一个十分普遍而严重的问题。本文结合泰安市的具体情况 ,论述了地下水超采的危害和防治措施。     

OrthoBASE在航空图像正射纠正中的应用

本文介绍了ERDAS IMAGINE软件中的OrthoBASE模块在航空像片正射纠正中应用，使用这种方法效率比常规单片纠正的方法提高一倍左右，并可以节省大量的外业控制点，自动化程度有较大提高。     

基于GIS的城镇土地定级估价方法研究

根据城镇土地定级估价的工作特点,研究基于GIS技术的城镇土地定级估价方法。在较为系统地分析了我国现行城镇土地定级估价方法的基础上,提出了在GIS支持下进行城镇土地定级和基准地价评估的基本方法和步骤,并以ArcCAD为支撑软件,进行了城镇土地定级估价软件的设计研制。用于自动完成定级估价因素/子分值计算。土地级别确定、基准地价测算及成果输入等,并以浙江城镇为例进行了应用实验。     

Design of conceptual model in digital map database

The components of map information are analyzed theoretically in this paper, and the map information includes mainly the spatial information, at tributive information and temporal characteristics information. Then the digital map entity is defined according to construction characteristics of the map information. Finally, on the basis of the analyses of the construction characteristics of digital map entity and present conceptual model of digital map database, an abstracted conceptual model of digital map database is presented. And the Normal Form theory of relational database is discussed particularly.