NUMERICAL EXPERIMENT OF MEDIUM-RANGE CHANGE OF THE SUBTROPICAL HIGH Ⅱ. THE INFLUENCE OF THE HEATING SOURCE OVER WESTERN TROPICAL PACIFIC

Numerical experiments are carried out using a global spectral model to study the role of an ideal heating source over the western tropical Pacific region in a medium-term weather process that marks the western advancement of the subtropical high in mid-June 1979. The result has indicated that the effect of the ideal heating source is evident in about 4 days after the inclusion in the high and the circulation at mid-and high-latitudes over the eastern part of China; the disturbance produced over the tropical ocean first transfers towards the northwest along the easterly flow on the southern edge of the subtropical high and then divides into two branches as it moves over the westerly over the mid-latitude area, one continuing the journey northwestward and the other turning to the northeast by east, resulting in changes in the subtropical high and the westerly through combined action.     

山西省地电监测能力综合评价

以影响地电观测资料可信度的因素及在一定有效监控能力范围之内的映震能力作为地电监测能力的综合评价指标,对山西省的４个地电台站逐一进行了分析研究,得出了山西地电阻率对３００ｋｍ以内５．０级以上中强地震有一定监测能力的结论。     

EXPERIMENTAL STUDY ON RIVER TRAINING MEASURES TO CONTROL BED EROSION

IINTRODUCTIONRiversareanimportantcomponentofournatUralworld.ForthePurposeoffloodprotection,inlandshippingandlandutilization,manyrivershavebeenregulatedornarrowedinaschematic,monotonousmanner.Theriverbedandbanksaresmoothedinordertoreducetheflowresistanceandtoincreasetheflowcapacity.Thesetraditionalrivertrainingmeasures,whichcontradictnlderalevolutionlawofrivers,exertharmfuleffectsontheriverecosystemand"thealenvironmentalongtherivers.Theprimaryequilibriumofthebedloadtransportofriversaredam…     

云南春季冰雹、大风天气的中尺度扰动特征

应用Ｂａｒｎｕｓ带通滤波方法,对１９９７年春季两次发生在滇南的冰雹、大风天气进行滤波分析,结果表明：冰雹大风发生前,昆明准确止锋附近低层有中尺度的扰动波列通过,风雹地区包括一个上升运动中和下沉运动中心。     

大型模拟地震振动台的特殊控制

阐述了多度大型地震模拟振动台由于试件重心高,偏心以及几何等原因在一个轴线方向上振动量,造成对其他轴线方向运动的干扰,同时介绍了克服这些干扰的控制原理。     

Fish assemblage structure on sandy beaches with different anthropogenic influences and proximity of spawning grounds

Fish assemblages in an insular (preserved) and a continental (disturbed) sandy beach were compared to assess any changes that could be attributed to anthropogenic influences and/or the proximity of the fish spawning grounds. We expected that the closer geographical position to the spawning grounds and the small amount of anthropogenic disturbance on the insular beach would be likely to provide more suitable conditions for early fish development compared with the continental beach. A total of 192 samples (96 in each beach) were taken, yielding 68 fish species, mostly young‐of‐the‐year. Fish assemblage structure differed significantly between the two beaches. Moreover, the insular beach had higher number of species, number of individuals and biomass compared with the continental beach. The commercially important Clupeiformes Harengula clupeola, Anchoa tricolor and Anchoa januaria, Perciformes Micropogonias furnieri and Mugiliformes Mugil liza were typical species on the insular beach, partitioning the seasonal use of the beach. On the other hand, a few abundant non‐commercial species, mainly the Atheriniformes Atherinella brasiliensis and the Perciformes Eucinostomus argenteus and Diapterus rhombeus, occurred all year round at the continental beach. The high fish richness and abundance and the more conspicuous species turnover across seasons on the insular beach are probable indications of more complex and dynamic organization of the communities favored by better geographical position and less anthropogenic disturbance in the area.     

Diagnostic Analysis of Wave Action Density During Heavy Rainfall Caused by Landfalling Typhoon

Based on prior investigation, this work defined a new thermodynamic shear advection parameter, which combines the vertical component of convective vorticity vector, horizontal divergence, and vertical gradient of generalized potential temperature. The interaction between waves and fundamental states was computed for the heavyrainfall event generated by landfalling typhoon“Morakot”. The analysis data was produced by ADAS [ARPS(Advanced Regional Prediction System) Data Analysis System] combined wi...     

Numerical modeling of local scour due to submerged wall jets using a strict vertex-based,terrain conformal,moving-mesh technique in OpenFOAM

This study presents the implementation and validation of a new sediment-scour model with a strict vertex-based,terrain conformal,moving-mesh technique within the framework of OpenFOAM.OpenFOAM lacks the ability to simulate large-amplitude motion needed for analysis of sediment-scour problems,and,thus,its application normally is restricted to small-amplitude cases to prevent computational divergence due to mesh deterioration.The proposed simple,moving-mesh technique in OpenFOAM is implemented to overcome the shortcomings of the conventional automatic mesh-motion techniques in handling large-amplitude moving geometries.The model is used to simulate a simple case of prescribed boundary motion,a previous experiment in the literature,and a new laboratory experiment for local scour due to submerged wall jets.The results are compared with both the experimental and other numerical results.The comparisons demonstrate that the proposed model has the novel advantage of allowing for more severe topographic variations,and can provide more reliable predictions for the key characteristics and evolution of the bed profiles in wall jet scour problems.Furthermore,to improve the practice of modeling wall jet scour,various turbulence modeling approaches and bedload equations also are evaluated and compared.     

楼板振动概率分析的微分方程方法

本文针对作用于楼板上的多台机器扰和的复杂特性。给出了一个较接近于实际的随机扰力模型，从理论上建立了楼板振地国频率分析的微分方程方法，对于给定的随机扰和模型，给出了结构响应统计参数的计算公式，使得对楼板的随机振动分析得到深入，在计算机上得到简化。