Estimation of Water Particle Velocities by Empirical Transfer Function     

Chiu Yung-Fang Kuo Yi-Yu Chief of Coastal Engineering Division 《中国海洋工程》1997,(4)

-In previous and this studies it appears that the linear and nonlinear wave theory can notaccurately and easily predict the water particle velocities.Therefore,different from the theoretical consider-ations,in this study we have attempted to determine the transfer function empirically.Laboratory experi-ments were performed under various wave conditions.The empirical formulas of the transfer function ofthe wave height,angular frequency and water particle velocity were obtained on the basis of these test databy dimensional analysis and regression analysis.In intermediate and deep water depth conditions,thetransfer function was only a function of a nondimensional parameter which is composed of the angular fre-quency,the depth of the velocity gauge under the still water level,water depth and the acceleration of grav-ity.Finally,the empirical formulas were compared with experimental data and observational data formpresent and Cavaleri's(1978)studies.The empirical formulas were found to be in sufficient correl  相似文献   

基于卫星短消息通信的大地测量信息传输技术     

ZHAO Dong-qing  CHEN Ri-gao  ZHANG Xi-guang 《测绘学院学报》2008,(2)

无线通信是大地测量内外业一体化生产中的瓶颈问题。首先介绍了大地测量信息传输系统的基本功能,给出了通信管理功能的基本结构,然后重点讨论了通信管理中的一些关键技术:用户终端与计算机控制程序之间的信息组织、利用CRC校验和多重确认进行误码控制、建立传输队列来防止信号失锁造成的信息拥塞。最后通过试验分析,验证了利用卫星短消息通信进行大地测量信息传输的可行性。  相似文献   

物权法对节约集约利用土地的法理解析——以青岛市崂山区分层出让建设用地使用权为例     

万磊 《山东地质》2008,(11):38-39

土地资源具有稀缺性和不可再生性,土地供给日渐紧张,拓展土地利用空间、将土地利用由平面趋向立体化发展的趋势日渐成熟。青岛市崂山区将建设用地使用权分层出让,不但垂范了法规政策,对区域经济的发展也具有很大的现实意义。  相似文献   

Inferring hydro-geothermal parameters from advectively perturbed thermal logs     

M. Verdoya  V. Pasquale  P. Chiozzi 《International Journal of Earth Sciences》2008,97(2):333-344

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非均匀月壤介质的被动微波辐射传输模拟   总被引：1，自引：1，他引：0  

孟治国  陈圣波  刘财  杜晓娟  吕航 《吉林大学学报(地球科学版)》2008,38(6)

基于非均匀月壤物理模型和辐射传输方程,模拟月壤介质中的微波辐射传输特性,探讨频率、月壤厚度等与月表亮温的关系。结果表明:在低频段,月壤微波辐射亮温的动态变化范围较大,可探测的月壤厚度大,3 GHz时的最大可探测月壤厚度达12.4 m;在高频段对应的可探测月壤厚度较小,特别是从50GHz往后的频率段内,最大可探测月壤厚度均小于2 m。不同频率的亮温-厚度变化曲线没有交叉点,且频率越高,所能探测的月壤厚度越小。根据模拟结果,建立了月壤厚度与亮温的查找表。基于查找表,利用单个波段的亮温数据即可得到月壤厚度信息。  相似文献   

Actinic flux and photolysis frequency comparison computations using the model PHOTOGT     

Carsten Blindauer  Vladimir Rozanov  John Philip Burrows 《Journal of Atmospheric Chemistry》1996,24(1):1-21

The accurate radiative transfer model GOMETRAN, initially designed to yield radiances at TOA in the wavelength range 240–790 nm, has been extended to allow for the computation of actinic fluxes down to 175 nm and for the calculation of photolysis frequencies in the atmosphere. The capability of the extended model PHOTOGT (PHOTOGOMETRAN) is demonstrated in a number of successful comparison studies both with recent experiments (ground-based, balloonborne, airborne) and model calculations of radiances, actinic fluxes and photolysis frequencies in the stratosphere and troposphere. In an atmospheric case study, the impact of new quantum yield data for the O₃ » O₂+O(¹ d) photodissociation channel on the photolytic production of O(¹ d) atoms in the lower atmosphere has been quantified.  相似文献   

Evolution of cool skin and direct air-sea gas transfer coefficient during daytime     

Alexander V. Soloviev  Peter Schlüssel 《Boundary-Layer Meteorology》1996,77(1):45-68

Absorption of solar radiation within the thermal molecular sublayer of the ocean can modify the temperature difference across the cool skin as well as the air-sea gas transfer. Our model of renewal type is based on the assumption that the thermal and diffusive molecular sublayers below the ocean surface undergo cyclic growth and destruction, the heat and gas transfer between the successive burst events are performed by molecular diffusion. The model has been upgraded to include heating due to solar radiation. The renewal time is parameterized as a function of the surface Richardson number and the Keulegan number. A Rayleigh number criterion characterizes the convective instability of the cool skin under solar heating. Under low wind speed conditions, the solar heating can damp the convective instability, strongly increasing the renewal time and correspondingly decreasing the interfacial gas exchange. In the ocean, an additional convective instability caused by salinity flux due to evaporation becomes of importance in such cases. The new parameterization is compared with the cool skin data obtained in the western equatorial Pacific during the Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment in February 1993. In combination with a model of the diurnal thermocline it describes main features of the field data both in nighttime and daytime. Under low wind speed conditions (< 5 m s^-1) diurnal variations of the sea surface temperature due to the formation of a diurnal thermocline were substantially larger than those across the cool skin. Under wind speeds > 5 m s^-1, diurnal variations of the surface temperature due to the variations of the thermal molecular sublayer become more important.  相似文献   

Modelling of the vertical fluxes of nitric acid,ammonia, and ammonium nitrate     

Gerhard Kramm  Ralph Dlugi 《Journal of Atmospheric Chemistry》1994,18(4):319-357

Results from numerical investigations regarding the exchange of HNO₃, NH₃, and NH₄NO₃ between the atmosphere and the biosphere are presented. The investigations were performed with a modified inferential method which is based on the generally accepted micrometeorological ideas of the transfer of momentum, sensible heat and matter near the Earth's surface and the chemical reactions among these nitrogen compounds. This modified inferential method calculates the micrometeorological quantities (such as the friction velocity and the fluxes of sensible and latent heat), the height-invariant fluxes of the composed chemically conservative trace species with group concentrationsc ₁=[HNO₃]+[NH₄NO₃] (total nitrate),c ₂=[NH₃]+[NH₄NO₃] (total ammonia), andc ₃=[HNO₃]-[NH₃] as well as the fluxes of the individual nitrogen compounds. The parameterization of the fluxes is based on the flux-gradient relationships in the turbulent region of the atmospheric surface layer. The modified inferential method requires only the data of wind velocity, temperature, humidity and concentrations (HNO₃, NH₃, and NH₄NO₃) measured at a reference height by stations of a monitoring network.  相似文献   

Energy transfer among Pb, Ce and Mn in fluorescent calcite from Kuerle, Xinjiang, China     

Aierken Sidike  X.-M. Wang  Alifu Sawuti  H.-J. Zhu  I. Kusachi  N. Yamashita 《Physics and Chemistry of Minerals》2006,33(8-9):559-566

Natural calcite from Kuerle, Xinjiang, China, shows orange-red fluorescence when exposed to short-wave ultraviolet (UV) light (Hg 253.7 nm). Photoluminescence (PL) emission and excitation spectra of the calcite are observed at room temperature in detail. The PL emission spectrum under 208 nm excitation consists of three bands: two UV bands at 325 and 355 nm and an orange-red band at 620 nm. The three bands are ascribed to Pb²⁺, Ce³⁺ and Mn²⁺, respectively, as activators. The Pb²⁺ excitation band is observed at 243 nm, and the Ce³⁺ excitation band at 295 nm. The Pb²⁺ excitation band is also observed by monitoring the Ce³⁺ fluorescence, and the Pb²⁺ and Ce³⁺ excitation bands, in addition to six Mn²⁺ excitation bands, are also observed by monitoring the Mn²⁺ fluorescence. These indicate that four types of the energy transfer can occur in calcite through the following processes: (1) Pb²⁺ → Ce³⁺, (2) Pb²⁺ → Mn²⁺, (3) Ce³⁺ → Mn²⁺ and (4) Pb²⁺ → Ce³⁺ → Mn²⁺.  相似文献   

引黄水在北大港水库蓄存期水质咸化的研究   总被引：10，自引：0，他引：10       下载免费PDF全文

赵文玉  王启山  吴国平  吴立波  孙增峰  郑力燕 《水科学进展》2005,16(6):763-766

依据引黄水在北大港水库蓄存期水质咸化的事实以及传质理论,定性地分析了引黄水水质咸化的主要原因,包括盐碱土传质作用、蒸发浓缩作用以及风的扰动加速传质作用等.在北大港水库旁修建了一个模拟试验水池,进行了现场模拟试验研究.依据水量平衡和氯离子总量平衡的原理,分别定量地计算了传质作用和蒸发浓缩作用对水质咸化影响的比重.结果表明,在模拟水池蓄水后的30 d内,传质作用对水质咸化影响的比重有随时间增加而增长的趋势;30 d后,传质作用对水质咸化影响的比重稳定在80%,蒸发浓缩作用对水质咸化影响的比重稳定在20%,说明导致水质咸化的最主要因素是盐碱土传质作用.  相似文献