Cloud to IDA: Efficient fragility assessment with limited scaling

Incremental dynamic analysis (IDA) leads to curves expressed in terms of structural response versus intensity, commonly known as the IDA curves. It is known that implementation of IDA usually involves significant computational effort and most often significant scaling of the original records to various intensity levels. Employing as the performance variable the critical demand to capacity ratio (DCR) throughout the structure, which is equal to unity at the onset of the limit state, facilitates the identification of the intensity values at the onset of a desired limit state and hence the implementation of the IDA procedure. Employing the structural response to un‐scaled records and the corresponding regression‐based response predictions (a.k.a., the “Cloud Analysis”) helps in identifying the range of intensity values corresponding to demand to capacity ratio values in the vicinity of unity. The Cloud to IDA procedure for structural fragility assessment is proposed on the premise of exploiting the Cloud Analysis results to obtain the IDA curves both with minimum number of analyses and minimum amount of scaling. The transverse frame of a shear‐critical 7‐story older RC building in Van Nuys, CA, which is modeled in Opensees with fiber‐section considering the flexural‐shear‐axial interactions and the bar slip, is employed as a case study. It is demonstrated, by comparing the results to IDA and other state of the art non‐linear dynamic procedures based on no scaling or spectral‐shape‐compatible scaling, that the Cloud to IDA procedure leads to reliable results in terms of structural fragility and risk for the prescribed limit state.     

基于云计算的九分量噪声互相关函数计算及其在China Array密集台阵数据的应用

提出一种基于云计算的九分量噪声互相关函数的计算方法,可以利用弹性的云计算服务,实现海量噪声互相关函数计算的分解和加速。本文将此技术应用于"中国地震科学台阵探测——南北地震带北段"674个宽频带台站2014~2015年的三分量连续记录,获取了所有台站间的九分量噪声互相关函数。总体计算共完成了约22万条台站对路径上近14.9亿条单天互相关函数的计算,整体平均耗时约为10.2h,完成等量计算,传统计算模式需要耗时近6个月,基于云计算的NCF计算技术实现了近400倍的加速,并可以弹性地扩充。分析了所得九分量噪声互相关函数中瑞利面波的ZH振幅比,并与天然地震中瑞利面波的振幅比进行了比较,验证了计算结果的可靠性。基于云计算的噪声互相关函数计算方法,为利用现代计算技术处理海量数据提供了重要参考。     

Improved Algorithms for the Measurement of Total Precipitable Water and Cloud Liquid Water from SARAL Microwave Radiometer Observations

SARAL carried onboard a radar altimeter that provides very precise measurements of the sea surface height (SSH). Like other altimetric missions, SARAL carries a passive microwave radiometer (PMR) for wet tropospheric correction to SSH. In the present study, new algorithms are developed for the retrieval of cloud liquid water (CLW) and total precipitable water vapor (TPW) over the global oceans from PMR measurements of the brightness temperatures. A radiative transfer and genetic algorithm based retrieval scheme is proposed for the estimation of CLW and TPW from SARAL PMR. The comparisons of CLW from PMR with independent measurements from GPM-GMI and SSMIS within and outside ±40° latitudes show correlation (R) of 0.86 and 0.83, bias of 0.7 and ?3.61?mg/cm², and root mean square error (RMSE) of 8.42 and 8.07?mg/cm², respectively. Similarly, TPW from PMR with GPM-GMI and SSMIS show R of 0.99 and 0.98, bias of ?0.04 and ?0.03?g/cm² and RMSE of 0.17 and 0.17?g/cm², respectively. The retrieval accuracy of CLW and TPW from the new algorithms is compared with these parameters provided in the SARAL geophysical data records as finished products, which showed substantial improvement in the quality of the parameters from the new algorithm.     

一个可用于实时计算的太阳辐射模型

拓展了Smith等(1984)关于海面辐照度的数值算法,给出了一个可实时计算海面和海水中太阳辐射强度的模型,通过计算1998年9月24日—10月7日以及1999年4月28日—5月11日渤海表面太阳辐射量(两个时间段内的辐照总量误差分别为0.27%和6.67%),显示出该模型与实测结果良好的适应性。另外,模型还揭示在不考虑其它限制因素的前提下,当浮游植物生物量处于较小的状态时,海水中的太阳辐射能促进浮游植物的快速生长,但是当浮游植物的生物量增大到一定程度时,由于对太阳辐射的遮蔽作用增强,浮游植物的生长明显受到抑制。     

A modelling study of aerosol processing by stratocumulus clouds and its impact on general circulation model parameterisations of cloud and aerosol

A model of the aqueous phase processing of an aerosol population undergoing multiple cycling through a stratocumulus (Sc) cloud layer is presented. Results indicate that a significant modification of the aerosol properties is achieved following the first cycle through cloud. In a polluted atmosphere, further modification in subsequent cycles is seen to be hydrogen peroxide limited unless there is a flux of ammonia entering the system through cloud base (CB). The modification of the aerosol population is seen to have little effect on the microphysics (specifically the cloud droplet concentration and effective radius) of the processing cloud. However, it enables processed aerosols to subsequently act as efficient cloud condensation nuclei (CCN) in less vigorous clouds (as a result of reducing the critical supersaturation required to activate them). The effects of variations in the internal mixture of soluble components of aerosols on the microphysics of clouds forming on them are also investigated using the cloud model. A (K2) parameterisation of the effects of variations in internally mixed nitrate loadings on the cloud droplet number concentration is presented. The effects of applying this K2 correction to the droplet number (derived from a parameterisation based on sulphate) for the presence of nitrate in aerosol have been investigated using the HadAM3 version of the Hadley Centre General Circulation Model (GCM). The effect on global annual mean simulations of the indirect forcing and effective radius is small, but more pronounced regionally. Suggestions (based on model results and observations) for parameterising the size distribution and in-cloud growth of aerosols for use in GCMs are presented.     

Calculation of Probability of Cloud-Free Lines-of-Sightat Given Heights in Foshan,China

1.IntroductionWhetherornottherearecloudsonalineaswelookingatapointonthegroundfromapointintilespaceorinreverseorderisimportantforsuchpurposeasdeterminingtheutilityofopticalandinfraredsearchingandtrackingsystems.ProbabilityofCloud--FreeLines--of--Sight...     

The Local Interstellar Medium

Summary. Substantial progress in the field of the Local Interstellar Medium has been largely due to recent launches of space missions, mostly in the UV and X–ray domains, but also to ground-based observations, mainly in high resolution spectroscopy. However, a clear gap seems to remain between the wealth of new data and the theoretical understanding. This paper gives an overview of some observational aspects, with no attempt of completeness or doing justice to all the people involved in the field. As progress rarely evolves in straight paths, we can expect that our present picture of the solar system surroundings is not definitive. Received 30 October 1998     

"98.5"华南前汛期暴雨云微物理场数值模拟分析

为了进一步理解暴雨发生过程中云微物理场的演变和云微物理过程与动力、热力过程的相互作用,利用非静力中尺度数值模式MM5对1998年5月23~24日的华南暴雨过程进行了模拟,并详细分析了模拟结果。分析结果表明:利用混合冰相显式物理方案比其它方案模拟的降水更接近实际情况;云微物理场的模拟显示没有雪出现,这可能是华南降水云微物理的特点;每小时降水量有先减弱后又增强的趋势,暴雨过程中云的各微物理量的变化趋势与其一致;云的发展与良好的热力动力条件互相作用、共同加强,由南风带来的充足的水汽和热量为其发展提供前提条件,凝结潜热使上升运动向更高处伸展。     

地震信息化共用服务平台设计与实现

随着信息技术的飞速发展和信息化的推进,各个项目建设均要对硬件、网络、数据库、软件平台和系统进行重复的规划与建设,项目建设的系统越多,操作系统和应用服务的部署和运维就面临着越大的挑战,同时也造成了大量硬件资源的浪费,需要较高的成本进行维护.本文介绍了地震信息化项目中,利用云计算和大数据技术构建地震信息化共用服务平台,通过...     

建立在数值预报系统上的航空气象要素预报试验

文章介绍了建立在数值预报基础上的航空气象要素（颠簸、积冰和云等）预报技术，给出了预报颠簸强度的晴空湍流指数和预报积冰的积冰强度和积冰严重性指数，并利用预报模式进行了模式成云预报和云区诊断分析，给出了一些具体的模拟及预报试验结果。