Seasonal Variation and Physical Properties of the Cloud System over Southeastern China Derived from Cloud Sat Products

Based on the National Centers for Environmental Prediction（NCEP） and Climate Prediction Center（CPC） Merged Analysis of Precipitation（CMAP） data and Cloud Sat products, the seasonal variations of the cloud properties, vertical occurrence frequency, and ice water content of clouds over southeastern China were investigated in this study. In the Cloud Sat data, a significant alternation in high or low cloud patterns was observed from winter to summer over southeastern China. It was found that the East Asian Summer Monsoon（EASM） circulation and its transport of moisture leads to a conditional instability, which benefits the local upward motion in summer, and thereby results in an increased amount of high cloud. The deep convective cloud centers were found to coincide well with the northward march of the EASM, while cirrus lagged slightly behind the convection center and coincided well with the outflow and meridional wind divergence of the EASM. Analysis of the radiative heating rates revealed that both the plentiful summer moisture and higher clouds are effective in destabilizing the atmosphere. Moreover, clouds heat the mid-troposphere and the cloud radiative heating is balanced by adiabatic cooling through upward motion, which causes meridional wind by the Sverdrup balance. The cloud heating–forced circulation was observed to coincide well with the EASM circulation, serving as a positive effect on EASM circulation.

ANALYSING THE CLOUD MICRO-AND MACRO-PHYSICAL PROPERTIES OF THE CYCLONE EYE WALL AND ITS SURROUNDING SPIRAL CLOUD BANDS BASED ON CLOUDSAT AND TRMM DATA

In this study, the micro-and macro-physical properties, thermal structure and precipitation characteristics of cyclone eye walls and their surrounding spiral clouds were analysed with Cloud Sat and TRMM data for five tropical cyclones(TCs) in 2013. The results show that the ice-phase clouds of a mature TC are mainly above 5 km. With increasing altitude, the cloud droplet effective radius decreases, and the particle number concentration increases. Ice water content first increases and then decreases with increasing height. In the eye area, in addition to the well-known warm-core area, another warm core is also apparent around the eye at a height of 8 to 15 km. The horizontal distribution of precipitation is characterized by large-scale stratiform precipitation mixed with independent convective precipitation. The height of precipitation is mostly below 7.5 km, and the heavy rain is mainly below 5 km. When the peripheral convective clouds are strong enough, ice particles would be generated, thus providing conditions that are favourable for the formation of precipitation below.

APPLICATIONS OF THE CLOUDSAT TROPICAL CYCLONE PRODUCT IN ANALYZING THE VERTICAL STRUCTURE OF TROPICAL CYCLONES OVER THE WESTERN PACIFIC

Cloud profiling radar(CPR) onboard Cloud Sat allows for deep penetration into dense clouds/precipitation. In this study, tropical cyclones(TCs) are classified into three stages as developing, mature, and decaying. The circular TC area with the radius of 500 km is divided into five regions. The vertical structure characteristics of 94 Western Pacific TCs at different stages in different regions from June 2006 to February 2014 are statistically quantified using the Cloud Sat tropical cyclone overpass product(the CSTC Product). Contoured frequency by altitude diagrams(CFADs) of radar reflectivity show an arc-like feature and exhibit opposite distributions with a boundary at 5 km. Bright bands are found at this altitude, indicating melting layers. Deep convective(DC) clouds have the largest occurrence probability in the inner region, while Ci clouds occur more frequently in the outer region at 10-15 km. As clouds have the second largest vertical scale after DC clouds. Distributions of Ac, Cu, and Ns clouds at different stages have few distinctions.As the altitude increases, the ice effective radius and the distribution width parameter decrease while the particle number concentration increases. Moist static energy(MSE), cloud thickness(CT), liquid water path(LWP), ice water path(IWP), water vapor(WV), and rain rate(RR) all diminish along the radial direction and are significantly larger at the mature stage. The average value of MSE at the developing stage is larger than that at the decaying stage.

热带气旋“桑美(2006)”冰云微物理属性垂直分布规律

利用2006年8月3日—11日CloudSat卫星的云反演资料,探讨了热带气旋"桑美(2006)"在形成期、发展成熟期和减弱期不同部位云中冰粒子的垂直分布规律。结果表明:星载雷达扫过热带气旋"桑美(2006)"不同部位时,云中冰粒子主要分布在5~16.5km高度;冰粒子等效半径随高度递增而递减,大值区主要分布在冰云下部;冰粒子数浓度随高度递增而递增,大值区主要分布在冰云上部;冰水含量的垂直分布呈单峰或双峰特征;星载雷达监测到的该热带气旋不同部位的冰粒子等效半径、冰粒子数浓度、冰水含量的最大值分布范围分别为107.9~177.7mm、123.8~827.9粒×L^(-1)、211~2858mg·m^(-3),最大值出现高度存在差异。

夏季念青唐古拉峰地区云结构分析

利用2006—2010年夏季6-8月Cloud Sat资料对念青唐古拉峰地区云水分布和云类型特征进行分析,从而为研究高原天气过程与其水循环过程的相互作用提供理论依据。结果表明,云水含量垂直分布结构与云类型有关,而冰川区和非冰川区云类型差异主要为降水云类型不同,其中有冰川覆盖的高山上空降水云以深厚对流云为主,无冰川覆盖的高山降水云类型以雨层云为主。念青唐古拉峰南坡冰川区云水平均含量为0.14 g/m^3,非冰川区云水平均含量为0.18 g/m^3,一定程度说明来自孟加拉湾的水汽在经过冰川附近时,多会产生降水,反映了冰川对水汽传输的阻碍作用。

基于OpenStack的云测试平台及其性能分析研究

云测试是基于云计算的软件测试新模式。在传统的软件测试中,当测试任务高并发、原有的硬件资源无法满足测试时间要求时,需要更换硬件资源、重新配置测试环境。使用云测试可以实现按需分配硬件资源、无需重新配置测试环境,因而比传统软件测试更能节省测试成本。介绍了如何在OpenStack云平台上配置和运行软件代码覆盖率测试工具SAT。实验表明,当测试任务高并发时,所搭建的云测试平台可以在不用重新配置环境的情况下满足用户对测试时间的要求,降低了用户测试成本。

雷暴云背景下星地量子通信链路多参数融合寻优策略

为降低雷暴云对星地量子通信链路的影响,提出了一种基于多参数融合的星地量子通信链路切换策略。仿真分析了雷暴云中大气带电粒子浓度和观测高度对量子纠缠度、信道容量以及链路误码率之间的关系。将量子纠缠度、信道容量、链路误码率这三个参数进行加权并利用该加权因子的阈值来寻找当前时刻最优卫星接入星地量子通信链路中。仿真结果表明,使用参数加权融合因子来进行链路切换可以提高切换的成功率,并改善切换过程中掉话率高的问题。因此,采用参数加权融合因子来进行链路切换,对星地量子通信链路的可靠性有明显改善。

一次暴雨过程云中液态水微物理属性垂直分布

采用美国宇航局NASA的Cloud Sat卫星加载的云廓线雷达反演资料2B-CWC-RVOD和2B-CLDCLASS,以2008年4月28日发生在新疆北部沿天山一带的暴雨过程为例,分析云中液态水粒子有效半径、粒子数浓度、液态水含量等微物理属性的垂直分布特征。结果表明：此次暴雨过程中,云层分布在1-12 km高度,但云中液态水分布在6 km以下。云中液态水粒子半径的高值区出现在云层的中部,而峰值出现在约3 km高度处,云体边缘是低值区,且有效半径小于5μm的粒子在所有高度均有分布,占所有粒子的71.19%,在3-4 km高度层分布比例最大。大于20μm的粒子仅占1.27%,且集中分布于云中液态水中部2-5 km;液态水含量随云层高度的增加而有所降低,液态水含量大于500 mg·m^-3仅占0.08%,且分布在2-3 km;云中液态水粒子数浓度在垂直高度上存在明显的分层现象,云层越低,云中液态水粒子数浓度越高,粒子数浓度小于20个·cm^-3,占25.26%,且随高度的增加而增加,而浓度大于60个·cm^-3的粒子占12.28%,主要分布在2-5 km,且云层中部偏下处分布较多。