NUMERICAL SIMULATIONS AND DOPPLER RADAR DATA ANALYSIS OF A HAIL PROCESS IN HUAIHE RIVER BASIN     

LI Bai  XU Xiaofeng  ZHOU Kun 《Acta Meteorologica Sinica》2002,16(3):388-400

A hail process in Huaihe River Basin observed by CINRAD Doppler radar on 12May 2000 hasbeen simulated by using nonhydrostatic mesoscale numerical model MM5.The simulated wind fieldis analyzed and compared with Doppler radar wind data,both of them show that there was ameso-β cyclone around the hail region.Results show that this meso-β cyclone existed below 3 kmin the troposphere and its cyclonic circulation was very obvious below 1 km.The temperature andmoisture fields from the simulation are also analyzed.Furthermore,the storm-relativeenvironmental helicity and CAPE(convective available potential energy)are discussed.  相似文献   

GRAIN SIZE DISTRIBUTION OF SEDIMENT IN THE NORTHERN EAST CHINA SEA AND THE RELATIONSHIP WITH THE SEA CURRENTS     

LEI Kun    YANG Zuosheng  GUO Zhigang Doctoral student  College of marine geosciences  Ocean University of Qingdao    Qingdao  China Assistant prof.  the Chinese Research Acad 《国际泥沙研究》2002,17(2)

1 INTRODUCTION The East China Sea, one of the largest continental marginal seas in the world, receives large amount of suspended sediment from the land annually (Milliman and Meade, 1983; Shen, 1999). Since late Pleistocene, the deposition of the suspended sediment over the relict sandy sediment induces the complicated distribution of surface sediment (Fig. 1). Many studies have been done on the surface sediment distribution, sedimentation rate, concentration and dispersion of suspen…  相似文献   

EFFECTS OF DIABATIC PHYSICAL PROCESSES ON THE SIMULATION OF MESO-β SCALE STRUCTURE OF A SQUALL LINE SYSTEM          下载免费PDF全文

Gao Kun  Zhang Dalin 《Acta Meteorologica Sinica》1995,9(3):325-337

The effects of different convective parameterization,explicit moisture schemes and surface heat-ing on the meso-β scale structure of a squall line system are investigated,by using an improvedmesoscale model.It is found that the successful prediction of mesoscale convective systems hinges up-on not only the sub-grid scale convection,but also the resolvable scale phase change processes and thediurnal variation in the boundary layer.The simultaneous operation of the Fritsch-Chappell convectivescheme with parameterized moist downdrafts and the prognostic equations for cloud water (ice) andrainwater (snow) seems to be essential in simulating realistically MCSs and reducing or eliminatingthe unrealistic development of the CISK-like instability associated with the squall line system.  相似文献   

Iron-rich palygorskite： A potential clay material for contaminated environment remediation     

Zhen LI Lin YIN Kun HE 《中国地球化学学报》2006,25(B08):109-110

Palygorskite is a natural clay mineral characterized by a porous crystalline structure containing tetrahedral layers alloyed together by longitudinal sideline chains. Due to its sorptive and rheological properties, palygorskite is widely used in different industrial fields. In particular, palygorskite clays depict a high susceptibility to ion exchange, large special surface area, considerable porosity and thermal stability. The structural formula of the iron-rich palygorskite is established as： （Si 7.66 Al 0.34） （Al 1.08 Fe 0.81 Mg 1.99 Ti 0.05-1.07） 02 0（OH）2（OH2）4. The SEM images （Figure 1） reveal the fibers of high-iron palygorskite have the short-stick shape and the fibers can occur as the bundles of agglomerate needle-like structures. The interspaces of the structures increase the special surface area evidently. Compared to the iron-rich sample, the low-iron palygorskite fibers present as the compact stack without many interspaces and some fibers are flexural in shape. Tunnel-like rectangular microspores with the channels approximately 3.7-5.4 A in the crystal structure should also be considered. The iron-rich palygorskite has a normally higher special surface area （180-200 m^2/g） than other palygorskites （110-130 m^2/g） and the pore size is distributed from micropore （〈2 nm） to macropore （〉 100 nm）, which could extend the range of the adsorbate size. After acid leaching, the special surface area will increase up to 250-300 m^2/g. Previous studies proposed maximum sorption values of 37.2 mg/g for lead, 17.4 mg/g for copper, 7.11 mg/g for zinc and 5.83 mg/g for cadmium at pH 5-6. For excellent adsorption capacity of organic molecules, the clay has been applied in treatment of dye wastewater, decoloring edible oils and absorption of odorant molecules recently.  相似文献   

ADVANCE AND RETREAT OF THE SUMMER MONSOON IN CHINA          下载免费PDF全文

FONG Soi Kun  KU Chi Meng  HAO I Pan  WANG Anyu  WU Chisheng  LIN Wensh 《Acta Meteorologica Sinica》2000,14(1):1-12

By using the daily-14 year(1983—1996)NCEP/NCAR 2.5°×2.5° reanalysis data,wecarefully study in each pentad the advance and retreat of the summer monsoon in China and givento it a new definition.This definition considered the intensity of southwesterly winds at 850 hPatogether with its degree in temperature and moisture.The result revealed that:(1)The advance of the summer monsoon in China shows three abrupt northward shifts andfour relatively stationary stays.The four stable stages correspond to the peak of the pro-summerrainy period in South China,the“Meiyu”season in the Changjiang(Yangtze)-Huaihe RiverValleys.the rainy season in the downstream of the Huanghe(Yellow)Riyer Valleys and the rainyseason in northern China.The retreat of the summer monsoon is so fast that it totally retreatsfrom the mainland at about the mid-August.(2)The northward advance of summer monsoon in China is basically controlled by theseasonal variation latitudinally of the upper level planetary westerlies.It is in roughly accord withthe temporal variation in the position of 15 m s~(-1) isotaeh at 200 hPa.The fast retreat of thesummer monsoon is mainly due to the blocking effect of the Tibetan Plateau.(3)The advance of 500 hPa subtropical high of the western Pacific is also in aecordanee withthe advance of the summer monsoon in China.During the advancement of the summer monsoon,the eastward movement of the subtropical high shows great meaning that it creates the essentialcondition for the convergence of southward intrusion cold airs with the warm and humidsouthwesterly winds,which result in precipitation.There are three manifest eastward movementsof the subtropical high during its northward advancement.They coincide correspondingly to thebeginning of the peak of the pre-summer rainy period in South China,the“Meiyu”season in theChangjiang(Yangtze)-Huaihe River Valleys and finally the rainy season in northern China.Thewestern part of the subtropical high moves eastward to the region of Japan in late July and thebeginning of August.It then stays there for quite a long time which results in the straightmovement of cold airs intruding from the north to the east of Tibetan Plateau,i.e.the easternregion of China.This provides good condition for the fast southward retreat of the summermonsoon.(4)The intensifieation and development of the Tibetan high at 200 hPa are closely related to the eastward movement of the subtropical high,they often occur simultaneously.  相似文献   

3D Visualization of Landslide Deformation     

ZHANG Kun ZHANG Songlin 《地球空间信息科学学报》2007,10(1):67-70

The deformation of landslide is usually expressed in horizontal and vertical direction separately. Based on the X, Y, Z coor-dinates from a real monitoring project, a method to build three-dimensional(3D) model of landslide by constructing triangulated ir-regular network (TIN) and extruding contour lines is proposed. The almost imperceptible displacements of monitoring points are zoomed by two kind of exaggerating methods. The deformation process is replayed using 3D animation technique.  相似文献   

Three dimensional structure of the Luzong ore district, eastern China: electrical model from magnetotelluric data     

Kun Zhang  Jiayong Yan  Jinhua Zhao 《《地质学报》英文版》2018,92(Z1):229-230

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Tribological characteristics of high temperature aged FKM O-rings under abrasive conditions     

Kun Qin  Qin Zhou  YingLiang Feng  Kai Zhang  Yu Wang  BaiRu Xia 《《地质学报》英文版》2018,92(Z1):294-294

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Revision to Kowalskia from the Houhecun Fauna and a New Discovery of Tscherskia(Cricetidae,Rodentia) from the Youhe Fauna of Weinan,Shaanxi Province,China     

XIE Kun  ZHANG Yunxiang  LI Yongxiang 《《地质学报》英文版》2021,95(4):1073-1079

The fossil hamster (an isolated m1) from the early Early Pleistocene Houhecun fauna found in Dali, Weinan, Shaanxi, China, originally identified as Kowalskia dalinica, is reexamined. Its unique characters, including a high crown, very small degree of division of the anteroconid and relatively large size, is taken as evidence of its attribution to the genus Sinocricetus, instead of Kowalskia (junior synonym of Neocricetodon) suggested by the original author. Therefore, the specific name of the species established based on this m1 should be changed to S. dalinicus (Wang, 1988). S. dalinicus probably has a relatively close affinity with S. major Li, 2010, but there are still some obvious differences of characters between them. The discovery of S. dalinicus in the Houhecun fauna confirms that the genus indeed survived into the Pleistocene. A broken hamster mandible, which was found in Weinan, Shaanxi, China and belongs to the late Pliocene Youhe fauna, is also described here and identified as Tscherskia sp.. This specimen represents the earliest Tscherskia in Asia so far, but fails to refute the hypothesis that the genus originated in Europe during the early Pliocene.  相似文献   

基于CMIP5模拟预估21世纪珠江三角洲地区由于海平面上升而导致的淹没区面积     

夏江江  严中伟  周文  FONG Soi Kun  LEONG Ka Cheng  TANG Iu Man  CHANG S W  LEONG W K  靳少非 《海洋学报(英文版)》2015,34(9):78-84

Projections of potential submerged area due to sea level rise are helpful for improving understanding of the influence of ongoing global warming on coastal areas. The Ensemble Empirical Mode Decomposition method is used to adaptively decompose the sea level time series in order to extract the secular trend component. Then the linear relationship between the global mean sea level(GMSL) change and the Zhujiang(Pearl) River Delta(PRD)sea level change is calculated: an increase of 1.0 m in the GMSL corresponds to a 1.3 m(uncertainty interval from1.25 to 1.46 m) increase in the PRD. Based on this relationship and the GMSL rise projected by the Coupled Model Intercomparison Project Phase 5 under three greenhouse gas emission scenarios(representative concentration pathways, or RCPs, from low to high emission scenarios RCP2.6, RCP4.5, and RCP8.5), the PRD sea level is calculated and projected for the period 2006–2100. By around the year 2050, the PRD sea level will rise 0.29(0.21 to 0.40) m under RCP2.6, 0.31(0.22 to 0.42) m under RCP4.5, and 0.34(0.25 to 0.46) m under RCP8.5, respectively.By 2100, it will rise 0.59(0.36 to 0.88) m, 0.71(0.47 to 1.02) m, and 1.0(0.68 to 1.41) m, respectively. In addition,considering the extreme value of relative sea level due to land subsidence(i.e., 0.20 m) and that obtained from intermonthly variability(i.e., 0.33 m), the PRD sea level will rise 1.94 m by the year 2100 under the RCP8.5scenario with the upper uncertainty level(i.e., 1.41 m). Accordingly, the potential submerged area is 8.57×103 km2 for the PRD, about 1.3 times its present area.  相似文献