Accuracy of tretyakov precipitation gauge: Result of wmo intercomparison     

Daqing Yang  Barry E. Goodison  John R. Metcalfe  Valentin S. Golubev  Esko Elomaa  Thilo Gunther  Roy Bates  Timothy Pangburn  Clayton L. Hanson  Douglas Emerson  Voilete Copaciu  Janja Milkovic 《水文研究》1995,9(8):877-895

The Tretyakov non-recording precipitation gauge has been used historically as the official precipitation measurement instrument in the Russian (formerly the USSR) climatic and hydrological station network and in a number of other European countries. From 1986 to 1993, the accuracy and performance of this gauge were evaluated during the WMO Solid Precipitation Measurement Intercomparison at 11 stations in Canada, the USA, Russia, Germany, Finland, Romania and Croatia. The double fence intercomparison reference (DFIR) was the reference standard used at all the Intercomparison stations in the Intercomparison. The Intercomparison data collected at the different sites are compatible with respect to the catch ratio (measured/DFIR) for the same gauge, when compared using mean wind speed at the height of the gauge orifice during the observation period. The Intercomparison data for the Tretyakov gauge were compiled from measurements made at these WMO intercomparison sites. These data represent a variety of climates, terrains and exposures. The effects of environmental factors, such as wind speed, wind direction, type of precipitation and temperature, on gauge catch ratios were investigated. Wind speed was found to be the most important factor determining the gauge catch and air temperature had a secondary effect when precipitation was classified into snow, mixed and rain. The results of the analysis of gauge catch ratio versus wind speed and temperature on a daily time step are presented for various types of precipitation. Independent checks of the correction equations against the DFIR have been conducted at those Intercomparison stations and a good agreement (difference less than 10%) has been obtained. The use of such adjustment procedures should significantly improve the accuracy and homogeneity of gauge-measured precipitation data over large regions of the former USSR and central Europe.  相似文献   

Inversion Reconstruction of Gravity Potential Based on Gravity Gradients   总被引：1，自引：0，他引：1  

M. Dobróka  L. Völgyesi 《Mathematical Geosciences》2008,40(3):299-311

A new method was developed for the inversion reconstruction of gravity potential. This method offers the possibility to determine the potential function and all of its important derivatives using the common inversion of gravity gradients and the first derivatives of potential. Gravity gradients can be originated from Torsion balance measurements, while the first derivatives of potential can be derived from the deflections of the vertical data. Different fields having great importance can be originated from this reconstructed potential function at any points of the investigated area. The advantage of this method is that the solution can be performed by a significantly over-determined inverse problem. Test computations were performed for the inversion reconstruction of gravity potential. There were 248 torsion balance measurements and 13 points where the deflections of the vertical are known in our test area. This inversion algorithm is rather stable. Gravity potential, the first and the second derivatives of the potential were determined for the test area by this suggested method. This method gives a good possibility for a useful geodetic application; deflections of the vertical based on torsion balance measurements can be determined for the whole area for each torsion balance stations.  相似文献   

Salt tectonics in pull-apart basins with application to the Dead Sea Basin   总被引：1，自引：0，他引：1  

J. Smit  J.-P. Brun  X. Fort  S. Cloetingh  Z. Ben-Avraham 《Tectonophysics》2008,449(1-4):1-16

The Dead Sea Basin displays a broad range of salt-related structures that developed in a sinistral strike-slip tectonic environment: en échelon salt ridges, large salt diapirs, transverse oblique normal faults, salt walls and rollovers. Laboratory experiments are used to investigate the mechanics of salt tectonics in pull-apart systems. The results show that in an elongated pull-apart basin the basin fill, although decoupled from the underlying basement by a salt layer, remains frictionally coupled to the boundary. The basin fill, therefore, undergoes a strike-slip shear couple that simultaneously generates en échelon fold trains and oblique normal faults, trending mutually perpendicular. According to the orientation of basin boundaries, sedimentary cover deformation can be dominantly contractional or extensional, at the extremities of pull-apart basins forming either folds and thrusts or normal faults, respectively. These guidelines, applied to the analysis of the Dead Sea Basin, show that the various salt-related structures form a coherent set in the frame of a sinistral strike-slip shearing deformation of the sedimentary basin fill.  相似文献   

MC-ICP-MS高精度Cu、Zn同位素测试技术   总被引：4，自引：1，他引：3  

侯可军  李延河  田有荣  秦燕  谢桂青 《矿床地质》2008,27(6):774-781

过渡族元素同位素是国际上同位素地球化学研究的热点。测试技术的限制是制约过渡元素同位素研究发展的关键。笔者利用Neptune型多接收等离子质谱(MC-ICP-MS),采用Cu、Zn互为内标的方法对仪器的质量歧视进行了校正,对基质效应和测试方法的重现性进行了检验,建立了高精度的Cu、Zn同位素测试技术。在5个月内对实验室标准IMRCu和IMRZn进行了测量,结果分别为δ65CuNIST976=(0.34±0.08)‰(2SD,n=32),δ66ZnJMCZn=(-9.64±0.05)‰(2SD,n=26),δ67ZnJMCZn=(-14.37±0.16)‰(2SD,n=26),δ68ZnJMCZn=(-19.01±0.08)‰(2SD,n=26),分析精度达到国际同类实验室先进水平。对Cu、Zn同位素参考物质进行了对比测量,分析结果与报道值在误差范围内完全一致。  相似文献   

Fine-Scale Measurements Of Turbulence In The Lower Troposphere: An Intercomparison Between A Kite- And Balloon-Borne, And A Helicopter-Borne Measurement System     

Andreas Muschinski  Ror Frehich  Mike Jensen  Ron Hugo  Axel Hoff  Frank Eaton  Ben Balsley 《Boundary-Layer Meteorology》2001,98(2):219-250

Two state-of-the-art, high-resolution, in situ turbulence measurement systems, which can be deployed at altitudes well above the atmospheric surface layer, are compared: the Tethered Lifting System (TLS) of the Cooperative Institute for Research in Environmental Sciences (CIRES)at the University of Colorado, Boulder, Colorado, and the helicopter-borneturbulence measurement system HELIPOD of the Technical UniversityBraunschweig, Germany, and the University of Hanover, Germany. Whilethe CIRES TLS is a fixed-point platform, HELIPOD is a moving platform.On the basis of data taken with the two systems in separate field campaigns,the system capabilities are quantified and discussed. Criteria for instrumentalrequirements are presented. It is shown that both the CIRES TLS and HELIPODare well suited for measuring fine-scale turbulence that is characterized by very small temperature structure parameters 10⁶ K² m^–2/3 and smaller) and very small energy dissipation rates (10^-7 m² s^-3 and smaller). The authors are not aware of any other turbulence measurement systems that have similar capabilities and can be deployed at altitudes of up to several kilometres. The HELIPOD is ideal for high-resolution horizontal measurements while the TLS is ideal for high-resolution vertical measurements using multiple sensors attached to a suspended line.  相似文献   

Regional Fluxes Of Momentum And Sensible Heat Over A Sub-Arctic Landscape During Late Winter     

Ekaterine Batchvarova  Svan-Erik Gryning  Charlotte Bay Hasager 《Boundary-Layer Meteorology》2001,99(3):489-507

Based on measurements at Sodankylä Meteorological Observatory the regional (aggregated) momentum and sensible heat fluxes are estimated for two days over a site in Finnish Lapland during late winter. The forest covers 49% of the area. The study shows that the forest dominates and controls the regional fluxes of momentum and sensible heat in different ways. The regional momentum flux is found to be 10–20% smaller than the measured momentum flux over the forest, and the regional sensible heat flux is estimated to be 30–50% of the values measured over a coniferous forest.The regional momentum flux is determined in two ways, both based on blending height theory. One is a parameterised method, the other represents a numerical solution of an aggregation model. The regional sensible heat flux is determined from the theory of mixed-layer growth. At near neutral conditions the regional momentum flux can be determined independently of the regional sensible heat flux. At unstable conditions the two models become coupled.The information that is needed by the parameterised blending height method and by the mixed-layer evolution method in order to derive the regional fluxes of momentum and sensible heat can be obtained from radiosonde profiles of wind speed and temperature.  相似文献   

STUDY ON APPLICATIONS OF C-BAND DUAL LINEAR POLARIZATION RADAR IN METEOROLOGY   总被引：4，自引：0，他引：4       下载免费PDF全文

徐宝祥  王致君  蔡启铭  刘黎平  张鸿发  楚荣忠 《Acta Meteorologica Sinica》1991,(3)

Theoretical study and development of a dual linear polarization weather radar in China are briefly presented.Also discussed are the potential uses of the new radar system in improving the accuracy of areal rainfall measure-ments and analysing the spacial structure of storms and distribution of hydrometecrs in clouds based on theradar observational data from the field experimcnts during the summers of 1987—1989. The results indicatethat a C-band dual polarization weather radar, after considering the microwave attenuation correction, may beemployed to quantitatively measure rainfall and to monitor heavy rain and flood events and becomes an impor-rant means to study storm structure.  相似文献   

PRELIMINARY STUDY ON THE CONDUCTIVITY STRUCTURE OF THE CRUST AND UPPER MANTLE: THIRD REPORT ON THE GEOSCIENCE TRANSECT FROM XIANGSHUI, JIANGSU, TO MANDAL, NEI MONGOL          下载免费PDF全文

Jiang Zhao  Sun Jie  Xu Chang-fang Wang Ji-jun  Shi Shu-lin 《地震地质》1990,12(3):200

The features of deep conductivity structure along Xiangshui-Mandal Geoscience Transect are described in this paper basing on newly obtained magnetotelluric data. Large resistivity contrasts can be found on both borders of North China platform. The depth of the crustal high conductivity layer changes abruptly from 21 km to 34 km beneath Nei Mongol fold system on the northwestern end of the transect. While it is absent beneath Subei-Jiaonan terrane on the southeastern end of the transect  相似文献   

Effects of eruption history and cooling rate on lava dome growth   总被引：1，自引：1，他引：0  

J. H. Fink  N. T. Bridges 《Bulletin of Volcanology》1995,57(4):229-239

To better understand the factors controlling the shapes of lava domes, laboratory simulations, measurements from active and prehistoric flows and dimensional analysis were used to explore how effusion history and cooling rate affect the final geometry of a dome. Fifty experiments were conducted in which a fixed volume of polyethylene glycol wax was injected into a tank of cold sucrose solution, either as one continuous event or as a series of shorter pulses separated by repose periods. When the wax cooling rates exceeded a critical minimum value, the dome aspect ratios (height/diameter) increased steadily with erupted volume over the course of a single experiment and the rate at which height increased with volume depended linearly on the time-averaged effusion rate. Thus the average effusion rate could be estimated from observations of how the dome shape changed with time. Our experimental results and dimensional analyses were compared with several groups of natural lava flows: the recently emplaced Mount St Helens and Soufrière domes, which had been carefully monitored while active; three sets of prehistoric rhyolite domes that varied in eruptive style and shape; and two sets of Holocene domes with similar shapes, but different compositions. Geometric measurements suggest that dome morphology can be directly correlated with effusion rate for domes of similar composition from the same locality, and that shape alone can be related to a dimensionless number comparing effusion rate and cooling rate. Extrapolation to the venusian pancake domes suggests that they formed from relatively viscous lavas extruded either episodically or at average effusion rates low enough to allow solidified surface crust to exert a dominating influence on the final morphology.  相似文献   

A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation,Alberta, Canada     

《Cretaceous Research》2016

A recently discovered articulated partial skeleton of Ornithomimus from the Upper Cretaceous Dinosaur Park Formation of Alberta, Canada is remarkable in the extent and quality of preservation of integumentary structures including feathers. It is the first ornithomimid to preserve a tail bearing extensive plumaceous feathers that are slightly more elongate in comparison to those present on the remainder of the body. However, the underside of the tail and the hind limb distal to the middle of the femur appear devoid of plumage. Overall, the plumage pattern in Ornithomimus is similar to that of Struthio camelus (ostrich) and other large palaeognaths, indicating a probable function in thermoregulation. The specimen also preserves the body outline around the legs, including a skin contour anterior to the femur, analogous to skin webs in extant birds. Whereas the knee web of birds bridges the knee to the abdomen, in Ornithomimus it spans from the mid-femoral shaft to the abdomen, and is herein referred to as an anterior femoral web. This is the first report of such soft tissue structures in non-avian theropods. It may indicate that the resting position of the femur was positioned more anteroventrally in ornithomimids than in most theropods, and in that sense may have been transitional to the situation in modern birds.  相似文献