Impact of Different Guidances on Sensitive Areas of Targeting Observations Based on the CNOP Method   总被引：1，自引：0，他引：1       下载免费PDF全文

TAN Xiaowei  WANG Bin  WANG Dongliang 《Acta Meteorologica Sinica》2010,24(1):17-30

The conditional nonlinear optimal perturbations(CNOPs) obtained by a fast algorithm are applied to determining the sensitive area for the targeting observation of Typhoon Matsa in 2005 using an operational regional prediction model-the Global/Regional Assimilation and PrEdiction System(GRAPES).Through a series of sensitivity experiments,several issues on targeting strategy design are discussed,including the effectivity of different guidances to determine the sensitive area(or targeting area) and the impa...  相似文献   

Temporal and Spatial Distributions of the Spring Persistent Rains over Southeastern China          下载免费PDF全文

万日金  吴国雄 《Acta Meteorologica Sinica》2009,23(5):598-608

  相似文献   

Temporal and Spatial Distributions of the Spring Persistent Rains over Southeastern China          下载免费PDF全文

WAN Rijin  WU Guoxiong 《Acta Meteorologica Sinica》2009,23(5):598-608

The spring persistent rains (SPR) over southeastern China (SEC) is a synoptic and climatic phenomenon that is unique in East Asia. Su cient evidence proves that it results from the mechanical and thermal effects of the giant Tibetan Plateau (TP), but its temporal span and spatial distribution are not clear at present.A climatological analysis of the NCEP/NCAR circulation and sensible heat data shows that at the 13th pentad of the solar year (1st pentad of March) there are remarkable increases in the sensible heating over the main and southeastern part of the TP, the southwesterly velocity over the southeastern flank of the TP and SEC, and rainfall over SEC, indicating the onset of the SPR.However, after the 27th pentad of the solar year (3rd pentad of May), these variables, except for the sensible heating over the main part of the TP, decrease rapidly. The ridge line of the subtropical high in the mid-low troposphere over the South China Sea (SCS) slopes northward instead of southward as before. The rain belt center over SEC shifts to the SCS and the SCS monsoon breaks out, indicating the end of the SPR. Hence, it is reasonable to define the SPR temporal span from the 13th to 27th pentad of the solar year. Data analysis and numerical sensitivity experiments show that, although the warm and cold airs converge at about 30°N in the SPR period, the distribution and intensity of the SPR rain belt are obviously in influenced by the topography of the Nanling and Wuyi Mountains (NWM). The mountains can block and lift cold and warm airs, strengthening frontogenesis and rainfall. As a result, the axis of the SPR rain belt is superposed over that of the mountain range. Accordingly, the spatial distribution of the SPR extends over most of the SEC, more speci cally, to the south of the middle and lower reaches of the Yangtze River (30°N), and to the east of 110°E.  相似文献   

混合误差协方差用于集合平方根滤波同化的试验   总被引：1，自引：0，他引：1       下载免费PDF全文

邱晓滨  邱崇践 《高原气象》2009,28(6):1399-1407

在集合卡尔曼滤波方法中, 根据预报集合统计提供的依流型而变的预报误差协方差对同化起到决定性的作用。但在集合样本容量不足及模式存在系统误差时, 由预报集合估计的预报误差协方差会出现明显偏差。既要减小这种估计偏差对同化产生的影响而又不增加计算量, 一种可供选择的方法是将定常或准定常的高斯型预报误差协方差和由预报集合估计的预报误差协方差加权平均用于集合卡尔曼滤波同化。利用浅水方程模式, 通过观测系统模拟试验检验在不同的模式误差、 集合成员数以及观测密度条件下, 将这种混合预报误差协方差矩阵用于在集合平方根滤波的效果。试验结果表明, 当预报集合成员数较多而模式又无误差时, 不必采用混合的预报误差协方差矩阵, 否则, 采用混合的预报误差协方差矩阵都有可能改进分析和预报。混合预报误差协方差的最优的权重系数与模式误差关系密切, 模式误差越大, 定常预报误差协方差的权重越大。最优的权重系数与集合成员数及观测密度也有一定关系。  相似文献   

非对称性增温对农业生态系统影响研究进展   总被引：9，自引：0，他引：9       下载免费PDF全文

谭凯炎  房世波  任三学  张新时 《应用气象学报》2009,20(5):634-641

该文概述了北半球和我国气候变暖中增温的非对称性特征:北半球气候变暖存在明显的季节差异和昼夜不同步性, 大部分地区冬、春季升温高于夏、秋季, 日最低气温升幅是日最高气温升幅的2~3倍; 近50年我国近地表气温升高主要是最低气温明显上升的结果, 日最低气温升幅是日最气高温升幅的2~3倍, 与北半球基本一致; 升温最显著的季节为冬季和春季。在此基础上概述了非对称性增温对农业生态系统的影响, 论述了非对称性增温对农作物物候和农作物产量的影响, 得出最低气温升高促使整个生长季延长, 促使早春作物物候期提前, 但最低气温和最高气温对不同作物的物候以及同一作物的不同发育阶段影响不同。现有研究多采用模型或统计的方法研究气候变暖对作物生长的影响, 认为温度升高对作物有“强迫成熟”效应; 而现有的最低气温升高和最高气温升高对作物生长影响的研究结果并不一致。非对称性增温对农作物影响的实验研究极少, 且缺乏对模型模拟结果的实验验证。  相似文献   

河北开滦矿区晚古生代煤对CH_4/CO_2二元气体等温解吸特性     

张贝贝  代世峰  雒洋冰  宋宪存 《地质论评》2010,56(5):753-760

研究了河北开滦矿区不同变质程度的煤对不同配比CH4/CO2二元气体等温解吸特性,并用扩展Langmuir方程的推论计算了CH4/CO2二元气体各组分在吸附相中的浓度,分析了其变化特征。结果表明:在开滦矿区煤对CH4/CO2二元气体解吸过程中,中等变质程度煤(Ro=1.21%)对混合气体的吸附能力大于低变质程度煤(Ro=0.58%),且混合气体中CO2浓度越大,总吸附量越多。吸附相中CH4的相对浓度是逐渐降低的,CO2的相对浓度是逐渐升高的。开滦矿区中等变质程度煤相对于低变质程度煤,用CO2气体置换煤层中CH4,可以获得较高的单位压降CH4解吸率,注入CO2的量越多、相对浓度越高,其置换效果就越好,更适于往煤层注入CO2提高煤层气产量技术的实施。  相似文献   

咸淡水过渡带的多组分离子交换行为研究          下载免费PDF全文

任加国  武倩倩 《中国地质》2010,37(2):530-535

以大沽河下游海水入侵砂质含水层为研究对象,采集地下淡水、海水和含水介质样品,并测定其组成和性质。通过渗流装置模拟咸淡水驱替过程,测定驱替过程中含水介质的渗透性参数和主要离子的变化规律,并尝试用数值模拟方法定量研究水敏感性影响下的多组分离子交换过程。研究结果表明,海水驱替淡水情况下,Na+能将砂土吸附的Ca2+、Mg2+、K+交换出来,Na+-Ca2+、Na+-K+交换速度很快,而Na+-Mg2+交换反应持续时间较长;在淡水驱替海水的过程中,溶液中的Ca2+、Mg2+将介质吸附的Na+、K+交换出来,但Ca2+-Na+交换起主导作用。含水介质的动力学参数和突破曲线的拐点变化均进一步验证了咸淡过渡带的水敏感性现象,多组分离子的交换行为导致了水敏感现象的发生。  相似文献   

四川沐川石英砂岩精制提纯研究   总被引：1，自引：0，他引：1  

谭靖  王雷  杨林 《贵州地质》2010,27(4):312-316

在工艺矿物学研究的基础上,采用相应的提纯工艺,进行精制石英砂提纯探索试验,使矿石中SiO2品位由93%左右提高至99.0%以上,为提升该矿的利用价值提供技术支持。  相似文献   

Modeling experimental study on weathering-leaching of Emeishan basalt and its relation with metallogenesis     

Fudong Wan  Xiaoqing Zhu  Tao Han  Zengsheng Li 《中国地球化学学报》2010,29(2):212-216

The Emeishan basalt has a high Cu background value (170×10-6 on average), and thus provides a ore-forming material source for copper ores. The collected samples were exposed in basalt lavas of the third segment of the Emeishan basalt eruptive cycle. By using a set of automatically cycling glass apparatuses, weathering-leaching experiments by three kinds of rainwater on the collected samples were carried out in the open system (at normal temperature and normal pressure). The analysis results showed that the most intensive export of Cu occurred under acidic rainwater-induced weathering-leaching conditions, almost 2-3 orders of magnitude the export of Cu by modern air rainwater, and 1-2 orders of magnitude higher than the export of Cu by CO2 rainwater. In addition, the total amount of Zn, Cu, U, Ni and Sr exported by acidic rainwater are greater than 1%. All this indicates that copper in the Emeishan basalt provided the copper source for Cu mineralization at the contact between the basalt and the Maokou Formation limestone at the bottom.  相似文献   

Measuring the speed of gravity at short distances: Sensitivity estimate     

Carlos Frajuca  Fabio da Silva Bortoli  Natan Vanelli Garcia  Nadja Simao Magalhaes 《Astronomische Nachrichten》2024,345(2-3):e230177

An experimental set up was proposed to determine the speed of gravitational signals traveling in air or in some other medium. It involves two vibrating masses—the emitters, which will be the sources of periodic tidal gravitational signals—and one sapphire-made mass that will act as a detector, positioned between the two emitters. The detector is planned to be suspended in vacuum and cooled down to 4.2 K, and its vibrational amplitude should be measured by a microwave signal (with ultra-low phase-noise) that is expected to resonate with the whispering gallery modes inside the detector. The mechanical and electrical quality factors of sapphire are quite high, yielding a very narrow detection band that reduces the detector sensitivity while amplifying the phase difference of the emitters' signals. The frequencies of the normal modes of the detector were previously determined using a finite element program. In this work, these frequencies are applied to the calculation of a first estimate of the sensitivity of the experiment.  相似文献