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    The petrogenesis of the Fenghuangshan pluton at the southern margin of the Cathaysia block
    YU Chenying; ZHANG Jian; YIN Changqing; LIU Jin; CHEN Guokai
       2019, 58 (4): 14-29.   doi:10.13471/j.cnki.acta.snus.2019.04.002
    Abstract244)      PDF (2860KB)(339)      

    Researching on the Mesozoic magmatism is critical to understanding the tectonic evolution of the Cathaysia Block, and therefore has become a hot topic in the past decade. Numerous petrological and geochemical studies were implemented in the eastern and middle parts of the block, but few studies focused the southernmost area in western Guandong Province. Therefore, the geochronological, geochemical, and Hf isotopic data from the Fenghuangshan granitoids, which are located at the southern margin of the Cathaysia Block, were used to constrain the crystallization age, petrogenesis and tectonic environment. The Fenghuangshan granitoids are dominated by biotitebearing monzogranites and biotite-bearing syenogranites. LA-ICP-MS zircon U-Pb data show that the former is (156±2) Ma and the latter is (158±3) Ma, respectively. All of the samples contain high silicon (SiO2=72.66%-76.63%), high alkali (Na2O+K2O =7.89%~9.43%), and low magnesium (MgO=0.05%-0.54%) concentrations. They show weakly peraluminous characteristics (A/CNK=1.02~1.04). The samples are enriched in Rb, Th, K and depleted in Ba, P, Sr, Ti, with a negative correlation between SiO2 and P2O5. Mineralogical and geochemical features suggest that the biotite-bearing syenogranite is I-type granite. By contrast, the biotite-bearing monzogranite falls into the area of highly fractionated I-type granite, with high differentiation index (DI=93.91-95.74), high Rb/Sr (=99.12-243.75) and Rb/Ba (=67.45-203.80) ratio, low consolidation index (SI=0.48-0.66) as well as significant negative Eu anomalies (δEu=0.01~0.02). The samples of monzogranite and syenogranite have relatively homogeneous Hf isotopic compositions, with εHf( t )  values and two-stage model ages (TDM2 ) of -9.4 to-5.4 and 1 545-1 804 Ma, respectively. The Hf isotopic features indicated that the monzogranites and syenogranites might share a same magma source, which was sourced from reworking of the Paleoproterozoic-Mesoproterozoic crust in the Jurassic. Combined with the previous studies, the Fenghuangshan pluton was suggested to be formed by underplating of the mantle-derived magma in an extensional tectonic setting, which was related to the roll-back or breakup of the subducting oceanic lithosphere.

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    Geochemistry characteristics and their geological significances of cherts in the tectonic belt from Mianlue,southern Qinling orogenic belt
    CHEN Shuo,ZHOU Yongzhang,ZHANG Yanlong,ZHOU Weili
       2019, 58 (5): 59-72.   doi:10.13471/j.cnki.acta.snus.2019.05.009
    Abstract197)      PDF (4516KB)(72)      

    Paleozoic cherts outcrops were widely developed in the Mianlue tectonic belt, which could reveal the sedimentary environment and tectonic background of southern Qinling orogenic belt. In Sanchazi area, the cherts were found in the Sanhekou Group of the Middle Devonian. Geochemical analyses showed that Sanchazi cherts were high in SiO2 (94.04%-98.08%, with a mean value of 96.92%) and low in Al2O3 and TiO2; and were relatively high in Ba and U, but was relatively low in Zr for trace elements. The U/Th and Ba/Sr ratios were relatively high too. ΣREE content was significantly low (7.61-51.04 μg/g, with an average valve of 2251 μg/g). PAASnormalized REE distribution pattern inclined to the left, rich in HREE and with positive Eu anomaly and negative Ce anomaly. The Al/(A1+Fe+Mn), Fe/Ti and (Fe+Mn)/Ti values indicated the origin of hydrothermal sedimentation of the cherts. Al/(Al+Fe), Al2O3/(Al2O3+Fe2O3+MnO), Al2O3/(Al2O3+Fe2O3), δCe and (La/Ce)N values indicated that the cherts were mainly formed in the continental margin. The values of (La/Lu)N, (La/Yb)N and δEu could be related to the hydrothermal activities controlled by the deep fractures. Th/U, U/Th, δU values indicated the cherts were formed in the anoxic depositional environment. The above-mentioned geochemical evidences inferred that Sanchazi cherts were formed in a sedimentary environment of rifted basin at continental margin in the north of South China Block during the Paleozoic. During the rifting period, while a series of extensional structures, such as rift or fault basin and syngenetic faults, were formed, accompanied magma activities could provide heat source for the thermal water, and the regional syngenetic faults provided the channel for upwelling of the thermal water. Hence, the convective hot water became rich in SiO2 through the leaching and dissolving of chemical composition from surrounding strata, and contributed to the forming of hydrothermal sediment cherts of different geologic ages in the Mianlue tectonic belt.

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    A similarity metric algorithm for multivariate time series based on information entropy and DTW
    QIAO Meiying;LIU Yuxiang;TAO Hui
       2019, 58 (2): 1-8.   doi:10.13471/j.cnki.acta.snus.2019.02.001
    Abstract93)      PDF (1321KB)(218)      

    This paper presents a method based on information entropy and dynamic time warping (DTW) to measure the similarity of multivariate time series. Firstly, DTW based on the Mahalanobis Distance considers the interrelationships among the variables of the multivariate time series, through the dynamic warping to align time series of different length. Secondly, adapting the information entropy theory, the Mahalanobis distance matrix is learned by minimizing the loss function, which can obtains the global optimal Markov matrix. In order to verify the effectiveness of the proposed algorithm, the five data sets in the UCI data set were used to classify through the nearest neighbor classification algorithm. Experimental results show that this method has higher classification accuracy and less time consumption than other methods, which proves the effectiveness of the proposed method.

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    The climate comfort model for evaluating heat-avoiding resorts in China
    LIU Yi;LU Zhanqing;CHEN Xinnuo
       2019, 58 (3): 22-31.   doi:10.13471/j.cnki.acta.snus.2019.03.003
    Abstract92)      PDF (1432KB)(172)      

    Based on theories in climatological study, this paper conducts a critical review upon several tourism climate comfort models. It then develops a new model called “STCI” (Summer Tourism Comfort Index) by absorbing insights from the model of Comprehensive Climate Comfort (CCC) and data from firsthand questionnaire survey. This paper applies the STCI model for evaluating places with good heat-avoiding condition for serving as summer tourism destinations in China, based on climate-related data from 244 cities. The results show that ranking lists under the STCI model, the CCC model and the report of “The Development of Summer Tourism in China in 2014” have significant differences. The conclusions are: (1) the STCI model identifies many potential summer tourism destinations in China which still have not been explored. These places have superior conditions for developing summer tourism, but they are yet to be effectively explored because of locational disadvantages or weak economic reputation. (2) Most of China‘s heat avoiding resorts are located in northeast (high-latitude) and southwest (high-altitude), whereas whether the northwest part and “North China” are suitable for summer tourism  remains controversial. (3) Among all the 244 cities, there are seven highly potential cities for developing summer tourism such as Suihua city in Heilongjiang Province and Baoshan City in Yunnan province. Based on these findings, this paper provides suggestions for governments, industries and tourists accordingly.

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    AKNN-Qalsh: an approximate KNN search extension for high-dimensional data in PostgreSQL
    ZHANG Chuhan;ZHANG Jiaqiao;FENG Jianlin
       2019, 58 (3): 79-85.   doi:10.13471/j.cnki.acta.snus.2019.03.010
    Abstract81)      PDF (1521KB)(140)      

    Complex data objects (such as pictures, text) are usually represented as high-dimensional feature vectors. The existing nearest neighbor search method KNN-Gist in PostgreSQL is based on the tree-structured index and cannot efficiently support the nearest neighbor search of high-dimensional data. The PostgreSQL system high-dimensional approximate nearest neighbor search extension: AKNN-Qalsh is introduced, which is based on the Locality-Sensitive Hashing scheme and supports approximate nearest neighbor search of large-scale, high-dimensional data objects. The effectiveness of the extension via extensive experiments on five real data sets is demonstrated.

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    Scene classification algorithm based on adaptively regional supervision
    CHEN Zhihong;HU Haifeng; MA Shuiping;YU Aobo
       2019, 58 (2): 9-14.   doi:10.13471/j.cnki.acta.snus.2019.02.002
    Abstract77)      PDF (1434KB)(142)      

    Deep Convolution Neural Network (DCNN) is a popular scene classification method. However, with the neural network deeper and wider, the difficulty of training network also increases. Some scholars have proposed crop images randomly to reduce the difficulty of network training, which will reduce the relevance of the cropped image to the label. To solve this, we propose a scene classification algorithm based on adaptively regional supervision, which is constructed by three parts: heat map generation layer, adaptively supervised cropping layer, and classification layer. The algorithm generates heat map for each image, adaptively crops the image based on the heat map, and finally classifies the cropped images, which improves the relevance of the cropped images to labels. Experiments on the 15-Scene and MIT Indoor datasets show our algorithm outperforms the original network architecture in training efficiency and recognition performance, which shows the accuracy and robustness of our algorithm.

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    Simulation analysis of seabed gas hydrate cutter suction mining single tooth crushing process
    WANG Guangshen, WANG Guorong, ZHONG Lin, ZHANG Yichi, QIU Shunzuo
       2019, 58 (5): 1-7.   doi:10.13471/j.cnki.acta.snus.2019.05.001
    Abstract76)      PDF (1856KB)(274)      

    Cutter suction gas hydrate solid state fluidized mechanical mining is one of technical solutions proposed for seabed hydrate mining. Based on the discrete element method (DEM), a quasi-3D numerical simulation model for single-tooth cutting hydrate is established to study the hydrate breaking process and the force of the cutter teeth in the cutting process. The results show that:1) Hydrate fracture still follows the failure mechanism of rock, pure hydrate is plastically destroyed, and marine hydrate deposition is brittle fracture; 2) the deeper of cutting thickness, the larger volume of the collapsed marine hydrate deposits; 3) when the cutting thickness is less than 8 mm, the cutting force increases linearly with the cutting thickness. The feasibility of study to crush hydrate by threedimensional discrete element method. The research results can provide basis for the design and mining parameters of the cutter suction mechanical mining and the cutter head.

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    Archaeomineralogy and provenance study of the stone hammers from ancient Hanxia nephrite mining site, Dunhuang
    YANG Jiong; ZHANG Yuefeng;QIU Zhili; CHEN Guoke; WANG Hui; ZHANG Yuyan; ZHENG Xinyu
       2019, 58 (4): 1-13.   doi:10.13471/j.cnki.acta.snus.2019.04.001
    Abstract76)      PDF (3782KB)(293)      

    The stone tool is a key symbol of productivity and production mode in the Stone Age. Ancient Hanxia nephrite mining site in Dunhuang was archeologically recognized as the oldest jade mining site discovered in China, its mining tools, i.e. stone hammers, and their rock materials including the petrological and geochemical characteristics may provide important information for revealing their material sources and the productivity at that time. In this paper, nine typical stone hammers were selected for petrological and geochemical analysis using polarizing microscope, XRF, and ICP-MS. The results showed that the stone hammers were made of diabase, basalt, dacite, granodiorite porphyrite and diorite porphyrite rocks. These rocks were characterized by the petrogeochemistry of igneous rocks formed within intraplate or volcanic arc environment, and are consistent with local igneous rocks within tens of kilometers of the site in Dunhuang area. Further comparison of the stone hammers and relative local igneous rocks in macroscopic features, microtexture, main and trace elements, and tectonic environment can infer that, except for some pebble hammers, the stone hammers were probably processed from local igneous rocks, especially those hard & dense-textured volcanic or subvolcanic rocks at Sanwei mountain nephrite mine or neighborly close-by, maybe 100 km around. Based on the scattered position of the stone hammers in the mining site and by contrasting with those stone hammers from other sites, we think the stone hammers were used as separation tools at Hanxia nephrite mining site, but more detailed research needs to do to find out their significance and value in understanding mining personnel from the stone hammer-reflected human behaviour and technical gestures in shape & structure in social system.

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    Characteristics ofδ13C and C/N in the Holocene organic material of borehole ZK19 in Lingdingyang bay and the records of east Asian Monsoon variation
    TAO Hui;WANG Jianhua;CHEN Huixian;WAXI Lali;WU Jiaxue
       2019, 58 (3): 1-12.   doi:10.13471/j.cnki.acta.snus.2019.03.001
    Abstract76)      PDF (2582KB)(233)      
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    Infinitely many solutions of a class of fractional Kirchhoff equation
    ZHANG Shengui
       2019, 58 (2): 142-147.   doi:10.13471/j.cnki.acta.snus.2019.02.018
    Abstract74)      PDF (640KB)(150)      

    Dirichlet boundary value problem for Kirchhoff equation with fractional p(x)-Laplacian operator is studied. When the nonlinear term is growing superlinearly, some sufficient conditions for the existence of infinitely many high energy solutions are obtained by using the fountain theorem in critical point theory.

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    A highly efficient algorithm for maximum cut on Halin graphs
    XU Li; LOU Dingjun; JIANG Yifan; QIN Zongrong
       2019, 58 (4): 90-98.   doi:10.13471/j.cnki.acta.snus.2019.04.009
    Abstract72)      PDF (2881KB)(87)      

    Given a graph  G=(V,E)  with each edge having a positive integer weight, and a positive integer  k , can V  be partitioned into two disjoint subsets V1 and V2  so that the sum of weights of the edges with one end in V1 and another end in V2 is at least k ? This problem is called the Maximum Cut Problem, which is an NPC problem. When the weight of each edge of G is 1, it is still an NPC problem. A highly efficient algorithm is designed to solve the Maximum Cut Problem with the weight of each edge to be 1 in Halin graphs. The time complexity of the algorithm is  O(n), where n=(|V(G)| .

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    Multi-DAG task scheduling algorithms
    LIU Lindong; WU Yilin
       2019, 58 (4): 99-107.   doi:10.13471/j.cnki.acta.snus.2019.04.010
    Abstract71)      PDF (1733KB)(76)      

    Multi-DAG task scheduling problem is a hotspot of current research in distributed heterogeneous environment. In order to improve the efficiency of task scheduling and resource utilization, the scheduling order of each DAG and the scheduling order between tasks within each DAG become the key task scheduling problem. A multi-DAG task scheduling model based on distributed heterogeneous computing environment and multi-DAG task scheduling algorithm MDTS(Multi-Dags Task Scheduling algorithm) are proposed. Firstly, multiple DAG tasks are merged into one DAG by adding an entry task node and an exit task node. secondly tasks are sorted according to the variance of computing cost and average communication cost of each task node. Finally, processors are scheduled according to the order from high to low based on HEFT algorithm. Experiments show that MDTS algorithm is superior to Sequential and Interleave algorithm in task scheduling makespan, average waiting time and average Slack.

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    The spatial-temporal features of population growth in fast immigrant city Shenzhen
    YANG Gao; ZHOU Chunshan; WANG Shaojian
       2019, 58 (2): 77-88.   doi:10.13471/j.cnki.acta.snus.2019.02.010
    Abstract71)      PDF (2265KB)(159)      

    The growth pattern and distribution characteristics of population in Shenzhen are analyzed using the statistical yearbook and the data from the 3rd to 6th census by mathematical statistics and GIS spatial analysis. The main results are as follows: (1) As a rapid immigration city, the population growth of Shenzhen was mainly influenced by economic factors and secondly by political factors. (2) The change of the permanent population is consistent with the change of the migrant population, and the fluctuation of population growth is relatively large. The dispersion coefficients are 0.54 and 0.66 from 1990 to 2000 and from 2000 to 2010, respectively. The outlying urban areas have mostly rapid growth in population, but those relatively remote areas show negative growth. (3) The “hot zones” are around the downtown areas; the “cold zones” lie mainly in the eastern region and Guangming new district. In addition, the index of population concentration is low and the distribution is relatively dispersed. The mean pointer center is showing the trend of the northwest direction. The spatial distribution of population density changed from “1 high center” to “1 high center+1 peripheral center” and then to “1 high center+2 peripheral center”. (4) The population growth of Shenzhen is stepping into maturity period from fast growing period, and the pattern of population distribution is in a transitional period from the absolute concentric to the relative concentric period.

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    CFD simulation and analysis of smoke dispersion in a subway fire
    CHEN Kecheng;XIE Jiabin;YAO Qinghe
       2019, 58 (2): 15-22.   doi:10.13471/j.cnki.acta.snus.2019.02.003
    Abstract70)      PDF (1704KB)(167)      

    To investigate the flow regularity of smoke in the subway station, Fire Dynamics Simulator is used to study the fire smoke spread in the Higher Education Mega Center North Station. The boundary conditions required for numerical simulation are determined based on the measured temperature and air velocity in the subway station. Large Eddy Simulation (LES) and Massive Passage Interface (MPI) are used to do realistic view simulation of the subway platform. As the result shows, when a fire breaks out in the middle of the platform, smoke concentration, CO concentration and temperature on the left part of the platform are about 133 percent, 75 percent and 41 percent respectively higher than those on the right part. Therefore, the right part of the platform is more secure for personnel evacuation.

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    Diurnal characteristics of autumn ASD-aerosols over Guangzhou
    TANG Yuming;DENG Ruru;XU Minduan;WU Yi
       2019, 58 (2): 58-67.   doi:10.13471/j.cnki.acta.snus.2019.02.008
    Abstract65)      PDF (2176KB)(120)      

     

    Aerosol optical parameters can indicate content and distribution of aerosol particles, and turbidity of atmosphere, which are of great significance to the research of aerosols. ASD FieldSpec3 spectroradiometer was used to measure the diurnal variation of aerosol particle contents over Guangzhou city on October 23, October 31, November 1, 2017 in typical autumn for inverting and analyzing its aerosol optical depth, Angstrom parameter, volume concentration and number concentration. The results showed that: 1) The daily variation of AOD was not notable and slightly different from day to day, but generally showed an increase trend.
    The wavelength indices of each day were high indicating that fine particles were principal components of aerosol particles in typical autumn day.  The turbidity coefficient was low showing that the atmosphere was in good condition.2) The AOD, volume concentration and number concentration of aerosol particles over Guangzhou increased continuously from 9 o’clock and reached a maximus at 15 o‘clock, which were possibly attributed to human activities. 3) The aerosol particles over Guangzhou showed a bimodal pattern in volume concentration. They were mainly composed of water-soluble and soot fine particles with sizes less than 0.1 μm, and showed a stable proportion between various aerosol particles, which did not change with time, indicating a relatively fixed pollution source. In addition, the slight amount of dust and  maritime particles represented that overall aerosol of Guangzhou was a hybrid  type made up of industrial and ocean type.
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    Optimization method of intersection guide sign setting based on artificial bee colony algorithm
    ZHANG Teng; HUANG Min; LIU Fang; ZHENG Jian
       2019, 58 (3): 131-139.   doi:10.13471/j.cnki.acta.snus.2019.03.016
    Abstract65)      PDF (2928KB)(125)      

    When there are many unreachable paths in the road network, there exists mutual influence between the paths, and the optimization cannot reach the overall optimum. Aiming at this phenomenon, a new integrated optimization model is presented. Firstly, the accessibility and comprehensive optimization of guide path are analyzed. Based on this, a comprehensive path optimization guidelines model is proposed with the optimization of the path length and the number of guidance information. Then combining with artificial bee colony algorithm and a neighborhood search strategy for road networks, the algorithm is designed to solve the problem of the concrete design. Finally, Guangzhou Higher Education Mega Center is chosen as the test area. The integrated optimization guidelines of the multiple guidance paths with the aim of Sun Yat-sen University are realized using the proposed model. In addition, comparing with single optimization results, experimental results show that the model can effectively solve the optimization problem for multiple path guidance, and the path quality is consider as a whole.

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    Exploring the properties of Levi-Civita and Kronecker symbols through antisymmetrization  
    PENG Junjin, LEI Liangjian
       2019, 58 (5): 26-32.   doi:10.13471/j.cnki.acta.snus.2019.05.004
    Abstract64)      PDF (888KB)(105)      

    In this paper, on basis of the determinant for the metric tensor, together with the identities got via anti-symmetrizing the Kronecker delta symbol and Levi-Civita tensor, we prove one of the properties of the Levi-Civita symbol (tensor), which shows that two Levi-Civita symbols (tensors) with the contraction for some or total indices can be expressed by a series of Kronecker delta symbols or the generalized Kronecker delta symbol. We further present two important deductions from the property of the Levi-Civita tensor, which are proved in other ways. Besides, we analyze several important properties for the generalized Kronecker delta symbol.

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    The number of ordered splits where the components of a positive integer n are not less than 2
    TANG Baoxiang; REN Han
       2019, 58 (4): 115-118.   doi:10.13471/j.cnki.acta.snus.2019.04.012
    Abstract63)      PDF (765KB)(104)      

    Firstly, the formula of the fraction of positive integer n is not more than 2 is obtained by using the recursive method. Secondly, the bijection of the ordered split sets between the fraction of positive integer  n is not more than 2 and the fraction of positive integer  n+2 is not less than 2 is established, so that the formula for calculating the ordered split number of the positive integer  n+2 is not less than 2 is obtained. Finally, when the fraction of positive integer  n is not more than 3 or 4, and is 2, 3 or 4, the recursive relations of the ordered split number are given.

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    Effect of intake stroke water injection on performance of diesel turbocharged engine
    WANG Sheng; YAO Qinghe; KWAN Trevor Hocksu
       2019, 58 (4): 130-135.   doi:10.13471/j.cnki.acta.snus.2019.04.014
    Abstract62)      PDF (2206KB)(88)      

    The AVL-FIRE software was used to study the effect of water injection to combustion in the YC6G series diesel engine during the intake stroke. Specifically, the influence of intake water injection on engine internal pressure, temperature, emission and ultimately performance was analyzed. Simulation results show that water injection of the supercharged engine has little effect on the average internal temperature and pressure of the engine cylinder but it can still reduce the peak temperature of the cylinder to a certain extent. The effect of water injection at the intake stroke on the exhaust emission is very significant. When the water injection mass fraction increased by 5%, soot production would decrease by approximately 10% and NOx emissions decreased to 0.21% over when water was not injected. Therefore, the intake stroke boosting water injection effectively improves the combustion inside the diesel engine and reduces exhaust emissions.

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    Application of radar and satellite data assimilation in a rainstorm forecast in Southern China
    ZHANG Shaoting; WANG Donghai; YU Xing;CHEN Quanliang;DING Weiyu
       2019, 58 (5): 80-93.   doi:10.13471/j.cnki.acta.snus.2019.05.011
    Abstract61)      PDF (4833KB)(81)      

    ARW-WRF and GSI 3D-Var methods were used to build a set of operational prediction systems and assimilate Doppler Weather Radar (DWR) reflectivity and velocity, Himawari-8 meteorological satellite AHI data. Regarding problems of data application and forecasting effect of unconventional data, multiple sets of comparative experiments were designed to perform simulation analysis and assessment of data assimilation (DA) results based on a case of severe precipitation process in southern China. The results show that during the heavy precipitation period in the coastal areas of Guangdong on 17-18 July 2017, the system can grasp the scope and intensity of precipitation and the simulation of radar reflectivity. Particularly, the assimilation of satellite data has ability to analyze cloud-water materials and weather process on the sea. Assimilating conventional data, radial velocity, reflectivity, and satellite data can improve simulation tactics such as temperature, wind vector, humidity, and precipitation. However, their prediction results are not absolutely superior to the test of certain types of data.

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