中国暴雨的科学与预报：改革开放40年研究成果   总被引：13，自引：4，他引：9  

罗亚丽  孙继松  李英  夏茹娣  杜宇  杨帅  张元春  陈静  代刊  沈学顺  陈昊明  周菲凡  刘屹岷  傅慎明  吴梦雯  肖天贵  陈杨瑞雪  黎慧琦  李明鑫 《气象学报》2020,78(3):419-450

总结了改革开放以来中国学者在暴雨科学与预报领域取得的重要研究进展和主要成果。其中,暴雨机理研究成果从重要天气系统、中国主要区域的暴雨、台风暴雨等3个方面分别进行综述,而暴雨预报技术研发与应用则从中国数值天气预报发展和暴雨预报客观方法两方面进行归纳。   相似文献   

2008年华南前汛期致洪暴雨特征及其对比分析   总被引：10，自引：5，他引：5  

王东海  夏茹娣  刘英 《气象学报》2011,69(1):137-148

着重对2008年华南前汛期持续性致洪暴雨的降水特征及成因进行了天气尺度的研究,并且对比分析了其与20世纪90年代以来华南前汛期洪灾较为严重的几年(1994、1998和2005年)的降水和环流场特征异同,主要得到以下结果:(1)根据影响系统和雨区分布的不同,将2008年华南前汛期降水过程分为4个阶段.第1阶段(5月26-...  相似文献   

Modelling Estuarine Biogeochemical Dynamics: From the Local to the Global Scale     

Pierre Regnier  Sandra Arndt  Nicolas Goossens  Chiara Volta  Goulven G. Laruelle  Ronny Lauerwald  Jens Hartmann 《Aquatic Geochemistry》2013,19(5-6):591-626

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Viscous computations of resonant absorption of MHD waves in flux tubes by fem     

R. Erdélyi  M. Goossens 《Astrophysics and Space Science》1994,213(2):273-298

A numerical code is presented for computing the stationary state of resonant absorption of MHD waves in cylindrical flux tubes in linear, compressible, and viscous MHD. The full viscosity stress tensor is included in the code with the five viscosity coefficients as given by Braginskii (1965). Also non-zero plasma pressure effects are taken into account, and the finite elements discretization with the Galerkin method has been used. The implementation of the stress tensor and the numerical accuracy of the tensorial viscous MHD code are scrutinized in test case. The test case involves the absorption of waves in cylindrical flux tubes considered by Lou (1990) and Goossens and Poedts (1992) in the context of absorption of acoustic oscillations. The results for the absorption rates obtained with the tensorial viscous code agree completely with the results obtained by Lou in a scalar viscous MHD and by Goossens and Poedts in resistive MHD. This verifies not only the complicated tensor viscous code but again proves that the absorption rate is independent of the actual dissipation mechanism.  相似文献   

Quantification of Aquatic Nano Particles after Different Steps of Bodensee Water Purification with Laser‐induced Breakdown Detection (LIBD)     

Tobias Bundschuh  Roger Knopp  Rudi Winzenbacher  Jae Il Kim  Rainer Kster 《洁净——土壤、空气、水》2001,29(1):7-15

The laser‐induced breakdown detection (LIBD) is a very sensitive method for the direct detection of colloids based on the plasma generation on single particles by a focused, pulsed laser beam and the detection of the produced shock wave or plasma light emission. For the determination of colloid sizes the light emission of single plasmas is detected by a microscope CCD‐camera system. With known mean particle diameter and breakdown probability the particle concentration can be calculated. The application of the LIBD to monitor the change of colloid concentration and size during the purification steps of drinking water at the Bodensee (Lake Constance, Germany) water purification plant is shown. The breakdown probability, correlating to colloid number density, decreases with every purification step. By addition of FeCl₃ as a precipitating agent and with an additional filtration step, not only suspended matter, but also colloids are effectively removed. After this process a remaining particle concentration of 50 ng/L and a mean particle diameter of 27 nm are found.  相似文献   

Superposition of aeolian dust ripple patterns as a result of changing wind directions     

Dirk Goossens 《地球表面变化过程与地形》1991,16(8):689-699

The effect of a change of wind direction on the orientation (and some other morphometric characteristics) of aeolian dust ripples is investigated. Ripple formation is simulated in a wind tunnel on surfaces that are already characterized by a previously established rippling. The effect of a wind rotation of 45 degrees, 90 degrees, and 180 degrees is examined. It is found that wind rotations of 45 and 180 degrees will lead towards a ripple alignment perpendicular to the last air flow. A wind rotation of 90 degrees, however, leads towards a ripple alignment perpendicular to the resultant wind direction. The faster the wind blows, the more this effect is expressed. No distinct relationship exists between the asymmetry of a dust ripple (and a dust ripple field) and the direction of the wind blowing as the ripples formed. As the orientation and asymmetry of aeolian dust ripples do not necessarily reflect the air flow direction during which the ripples formed, great care should be taken when reconstructing wind directions from such aeolian ripples.  相似文献   

Excitation of high-frequency Alfvén waves by plasma outflows from coronal reconnection events     

Voitenko  Yuriy  Goossens  Marcel 《Solar physics》2002,206(2):285-313

We study a kinetic excitation mechanism for high-frequency dispersive Alfvén waves in the solar corona by magnetic reconnection events. The ion-cyclotron and Cerenkov kinetic effects are important for these waves which we call the ion-cyclotron kinetic Alfvén waves (IC KAWs). The plasma outflowing from the reconnection site sets up a neutralized proton beam in the surrounding plasma, providing free energy for the excitation of waves. The dependence of the phase velocity of the IC KAW on the parallel wavenumber is different from that on the perpendicular wavenumber. The phase velocity is an increasing function of the perpendicular wavenumber and overtakes the Alfvén velocity for sufficiently large values of k . However, the phase velocity is a decreasing function of k , and sufficiently large values of k result in a phase velocity below the Alfvén velocity. As a result, the IC KAWs can undergo the Cerenkov resonance with both super- and sub-Alfvénic particles, and for the waves to be excited the outflow velocity does not need to be super-Alfvénic, as for KAWs, but the beam/Alfvén velocity ratio can span a wide range of values. High growth rates of the order of 10⁴ s^–1 are found for the values of the plasma parameters typical for the low solar corona. The waves excited by (sub-)Alfvénic beams are damped mainly due to kinetic wave-particle interactions with ions at the cyclotron resonance (ion-cyclotron damping), and with ions and electrons at the Cerenkov resonance (Landau damping). Therefore, IC KAWs can heat the plasma species of the corona in both the parallel and perpendicular direction, giving rise to an anisotropic heating of the ions. The observational consequences of the processes under study are discussed.  相似文献   

Effect of rock fragment embedding on the aeolian deposition of dust on stone‐covered surfaces     

Dirk Goossens 《地球表面变化过程与地形》2005,30(4):443-460

Many stone‐covered surfaces on Earth are subject to aeolian deposition of atmospheric dust. This study investigates how the deposition of dust is affected when rock fragments become gradually more embedded in the ground or, inversely, become more concentrated on the surface. Experiments were executed in an aeolian dust wind tunnel with eight different types of pebbles. The following parameters were measured: dust deposition on the pebbles, dust deposition between and underneath pebbles, total dust deposition (pebbles + inter‐pebble space), and the fraction, of total deposition, of dust caught by the pebbles alone. The absolute amount of dust deposition and the dust deposition density (dust deposition per unit surface) were studied for each parameter. The effects exerted by pebble size, pebble flattening, pebble elongation and wind speed were also investigated. Dust patterns on and around pebbles were also studied via flow visualization. The absolute amount of dust settling on pebbles decreases the more that the pebbles become embedded. Dust deposition density on pebbles, on the other hand, increases with embedding. The more pebbles become embedded in the soil, the more efficient the process of dust deposition on pebbles becomes. Dust deposition between and underneath pebbles increases with pebble embedding. Dust deposition density between and underneath pebbles is maximum at 50 per cent embedding, showing that in this area dust deposition is most efficient when pebbles are halfway embedded. Total deposition slightly decreases the more pebbles become embedded, but total dust deposition density increases with embedding. Aerodynamic flow separation and diverging and converging airflow play an important role in the process of dust deposition on stone‐covered surfaces. The more pebbles protrude above the soil, the more they act as an obstacle and the more they disturb the air and dust flow creating scouring zones, flow separation bubbles and shelter areas for the dust. All these effects diminish as pebbles become more embedded in the soil. However, perturbations in dust patterns remain visible until pebbles have disappeared entirely. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Integrated analysis of Landsat TM,airborne magnetic,and radiometric data,as an exploration tool for granite-related mineralization,Salamanca province,Western Spain     

Marc A. Goossens 《Natural Resources Research》1993,2(1):14-30

For successful application of remote sensing and data integration in regional mineral exploration, it is crucial that, prior to regional application, relations between geological setting, mineralizing processes, related anomalies, and available remote sensing data are thoroughly studied in a calibration area with known mineralization that is representative for the region of interest. Recognizing features that are diagnostic for mineralization and its setting using Landsat Thematic Mapper (TM) and airborne geophysical data is complicated for the following reasons: (1) The basic relation between geology and the original data is often obscured by complex data manipulation, obstructing the understanding of the final output. (2) The risk of removing potentially important information during the data interpretation is considerable. (3) The decision criteria with respect to the correctness of classifications are often arbitrary. (4) Error and quality assessments are often subjective and not reproducible under different circumstances. A data integration study is presented for a 20-km×20-km calibration area in Spain with known granite-related mineralization. The contact metamorphic setting is diagnostic for most mineral deposits. Therefore, TM and airborne data are used to map features predictive for contact metamorphic rocks. A concept of spatial reasoning is presented that reduces the damage caused by these problems: (1) The data manipulation is very straightforward and aimed at recognizing specific features known to be diagnostic for the setting in which mineralization is likely to occur. (2) Every step in the data manipulation is described in a quantitative way. (3) The nature of the pixels surrounding a classified pixel is considered when deciding whether the classification is correct. (4) Weights are assigned to the degree of uncertainty within an interpretation. (5) Integrating the interpreted and weighed data into a probability map highlights zones that are confirmed by all data sets, and thus are most reliably classified. This concept enables users of a careful and systematic analysis of the multiple spatial data sets to detect diagnostic features that are predictive for granite-related mineralization in this region.  相似文献   

On the existence of the continuous spectrum of ideal MHD in a 2D magnetostatic equilibrium     

M. Goossens  S. Poedts  D. Hermans 《Solar physics》1985,102(1-2):51-66

The continuous spectrum of a 2D magnetostatic equilibrium with y-invariance is derived. It is shown that the continuous spectrum is given by an eigenvalue problem on each magnetic surface and is related to the different behaviour of the equilibrium quantities in different magnetic surfaces. The special case of a uniform poloidal magnetic field in a 1D equilibrium that is stratified with height, has been considered in detail and it is found that there is no continuous spectrum. It is shown that this result relies completely on the artificial property that the behaviour of the equilibrium quantities along a magnetic field line is independent of the field line considered. As a consequence the non-existence of a continuous spectrum in a 1D equilibrium with a uniform magnetic field cannot be used to argue that the continuous spectrum has no physical relevance.Research Assistant of the Belgian National Fund for Scientific Research.  相似文献