Volume 39,Issue 4,2011 Table of Contents

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  • 1  Comparative Analysis of Four Initialization Schemes in Typhoon Numerical Simulation
    Wang Yunfeng Lu Qiang Wang Bin Yuan Jinnan Han Yueqi
    2011, 39(4):385-391.
    [Abstract](1559) [HTML](0) [PDF 6.29 M](1676)
    Abstract:
    In recent years, several Bogus schemes have been put forward to improve the initial thermodynamic and circumfluent structures of typhoons, which performed well in typhoon numerical forecasting. It has great significance for typhoon numerical simulation and forecasting to understand, compare, and improve various Bogus techniques. An introduction is made to four initialization schemes of typhoons, which include the Bogus data assimilation scheme (BDA)based on four dimensional variational data assimilation (4DVAR), the incidental Bogus scheme of MM5, the Bogus scheme advanced by Wang Guomin, and one used by the Institute of Tropical and Marine Meteorology in Guangzhou, and then the effects of these models in typhoon numerical forecasting are compared. The results show that the BDA scheme is obviously better for improving both typhoon track and intensity simulations.
    2  A Comparative Analysis of Two Geopotential Height Field Reanalysis Datasets in Plateau
    Xun Xueyi Hu Zeyong Sun Jun Cui Guifeng Xu Lijiao Sun Xin
    2011, 39(4):392-400.
    [Abstract](1661) [HTML](0) [PDF 7.92 M](1570)
    Abstract:
    Based on ERA40 and NCEPI (NCEP/NCAR version I) reanalysis datasets, the upperair observation datasets over the QinghaiXizang Plateau, and the data from the first Tibetan Plateau field experiment in 1979, the characteristics of geopotential heights over the QinghaiXizang Plateau are compared. Although there are some similarities, sensible differences among several reanalysis datasets are found. Comparatively speaking, the deviation of NCEPI reanalysis datasets from upperair observation datasets is the smallest, while that of ERA40 reanalysis datasets is the smallest over 200 hPa from 1980 to 1990 in the northern Plateau. Except that NCEPI reanalysis datasets are in better agreement with the upperair observation datasets over 200 hPa from 1980 to 1990, ERA40 reanalysis datasets are probably closer to reality on the interdecadal timescale in the central and southern Plateau. ERA40 reanalysis datasets show a better spatial similarity to the data from the first Tibetan Plateau field experiment than NCEPI reanalysis datasets.
    3  Characteristics of Precipitation Concentration Degree and Precipitation Concentration Period during Second Rainy Season in Guangdong
    Zhang Jinling Wang Ji Zou Juxiang Han Zhaoyu
    2011, 39(4):401-407.
    [Abstract](1466) [HTML](0) [PDF 5.74 M](1600)
    Abstract:
    By use of the pentad precipitation data from 23 stations in Guangdong Province during the second rainy season (July to September) from 1961 to 2006, the characteristics of the spatialtemporal distribution and variation of precipitation are analyzed in terms of the Precipitation Concentration Degree (PCD) and Precipitation Concentration Period (PCP). The results show that PCD and PCP can reflect well the spatialtemporal distribution of the precipitation. There was a weak descending trend and various periodic variations at interannual and decade scales in PCD in Guangdong Province during the second rainy season. The spatial distribution of PCD shows the characteristic of decreasing from north to south successively. PCD had a uneven distribution, more concentrative over the central part of Guangdong in rainy years than dry years. PCPs in rainy years were smaller than those in dry years. By the empirical orthogonal function (EOF) method, the first eigenvector of PCD shows the characteristic of identical increasing trend over the province, with the contours being northeastsouthwest oriented, but the second eigenvector is opposite from the east to the west. The circulation field analysis shows that in the high PCD years, the northern China was often controlled by high pressure systems at 1000 hPa and 500 hPa high fields, and there was usually a positive anomaly center in the height field, while the high pressure often extended southward, which converged with the warm and wet air, leading to strong precipitation.
    4  Trends of Cloud Optical Thickness and Cloud Effective Radius Variation in China
    Duan Jiao Liu Yu
    2011, 39(4):408-416.
    [Abstract](1843) [HTML](0) [PDF 8.74 M](2722)
    Abstract:
    The temporal and spatial characteristics of clouds over China are analyzed by using the ISCCP (International Satellite Cloud Climatology Project) monthly mean D2 data and MODIS (MODerateresolution Imaging Spectroradiometer)cloud data. The results show that over the past 20 years, the changes in cloud effective radius have the greatest effect on cloud optical thickness during summer, which means that the indirect effect of aerosol on climate may be the strongest during summer. The analysis of cloud optical thickness and effective radius changes also shows that the Yangtze River region and the QinghaiTibet Plateau region may be the areas influenced the most prominently by the indirect climatic effects of aerosols. Besides, the ice cloud optical thickness and effective diameter are associated with strong regional characteristics in China, which indicates that microphysical mechanisms in ice clouds are more complex than water clouds.
    5  TemporalSpatial Distribution of Precipitation in Chengdu
    Li Xinyi Xiao Guojie Bai Aijuan Shi Juan
    2011, 39(4):417-422.
    [Abstract](1706) [HTML](0) [PDF 4.67 M](1722)
    Abstract:
    The temporal trend and spatial distribution of precipitation during the last 50 years are analyzed on the basis of observation data from 12 stations over the Chengdu region. The results show that significant decreasing trends could be seen in annual precipitation, precipitation intensity in wet season, and maximum daily rainfall amount. The precipitation concentrates in summer,and the precipitation in July and August accounts for 47 percent of that of the total year. The annual precipitation and maximum daily rainfall amount decrease from west to east. The MK suddenchange test is conducted for these stations, and the results show that there exist suddenchanges in annual precipitation for most stations.
    6  Regionalization of Torrential Flood Disasters in Chongqing Based on GIS
    Tang Yuxue Liao Xianghua Li Jing Liu Tingting Min Fanhua
    2011, 39(4):423-428.
    [Abstract](1651) [HTML](0) [PDF 4.23 M](1992)
    Abstract:
    Through analyzing the dynamic conditions for torrential flood forming, the disasterbreeding environment, and the precipitation background, five parameters, including critical rainfall amount, annual precipitation, slope, the relief degree of land surface, and the annual number of heavy rain days, are identified as the main factors affecting the formation of flash flood disasters. Using the method of principal component analysis, the Chongqing torrentialflood disaster zoning model is established. Based on GIS technology, the spatial interpolation on various factors affecting floodinduced disasters by using inversedistance weighting method and then the calculation and segmentation for the raster layer are conducted. Chongqing is divided into four catalogues: high disasterprone area, disasterprone area, general area, and low disasterprone area, and the regionalization of torrentialflood disaster in Chongqing is achieved. The results show that Chongqing is an area attacked frequently by flood disasters. The high disasterprone areas are in northeast, with the annual occurrence frequency being more than 10 times; the disasterprone areas are in central and southeast parts, with the annual frequency more than 8 to 10 times; the low disasterprone areas are in western, with the annual frequency less than 6 times.
    7  Radar Characteristics of a DisasterInducing Lightning and Heavy Rain Event
    Ju Liling Niu Shengjie Chen Lianyou
    2011, 39(4):429-437.
    [Abstract](1471) [HTML](0) [PDF 7.98 M](1596)
    Abstract:
    Using the synchronous data of the lightning monitoring and warning network, Doppler radar, and regional AWS precipitation from a severe storm occurred in Qinhuangdao on 6 July 2009, a detailed analysis is carried out. The results show that the lightning process was dominated by negative ground flashes, with the maximum of lightning frequency being 712 times per hour; the lightning discharge trajectory was northwestsoutheast oriented, moving from north to south, with the hourly rainfall being more than 100 mm per hour when the maximum lightning frequency occurred; there was simultaneous phenomenon of lightning frequency and precipitation intensity. The disasterinducing lightning and heavy rain event was caused by two βscale convective cloud clusters at the different phases, whose structures and physical characteristics of the radar echoes were obviously different. Between 06:00 and 07:00, the radar echo intensity was 45 to 50 dBz, with the main echo having a compact structure and the cloud top height being more than 10.5 km; the radial velocity chart had obvious adversewind areas and a strong lowlevel convergence zone, and there was strong vortex ascending motion, with the liquid water content being 20 to 25 kg/m2. Between 14:00 and 15:00, the radar echo intensity was 50 to 55 dBz, and the main echo was composed of multiple convective cells, with a relatively loose structure; the cloud top height was greater than 12.8 km, and the radial velocity had obvious wind shear; the liquid water content in the afternoon was slightly more than that in the morning, being 25 to 30 kg/m2; the lightning density area corresponded well with strong echoes; the movement of dense lightning areas reflected the trends of strong convective cell movement; the radial velocity convergence zone corresponded with the frequent lightning activities; the distribution of radar echo tops was the same as the distribution of lightning activities.
    8  Characteristics of Satellite Images during a Heavy Rainfall in Ordos
    Chen Jing Li Liangwu Xiao Sujuan
    2011, 39(4):438-444.
    [Abstract](1671) [HTML](0) [PDF 6.00 M](1458)
    Abstract:
    By use of meteorological satellite images, MICAPS data, and conventional observation data,based on the principles and methods of meteorology and the application of weather satellite images to weather analysis and prediction, the process of a heavy rainfall event in Ordos is analyzed. The analysis results indicated: The heavy rainfall was induced mainly by the coactions of an active warmfront cloud system and a middleγ scale cloud storm nested in the bottom of the cloud cluster. Above the Europe and Asia at 500 hPa there was an eastwardmoving stepped westerly trough converging with the northward warmmoist air flow in the Hetao area to the west of the subtropical high. There was a shear line above 700 hPa, and the northern East China southeast wind jet to the north of the Jianghuai cyclone transported water vapor to the northwest. There were three watervapor transport channels conveying water vapor and energy to the Hetao area from the west, southwest, and southeast, respectively. There was a convective unstable stratification of cold at upper levels and warm at lower level. Heavy rainfall occurred in the front of the warmfront cloud zone in the area of the coldfront cloud band breaking, in combination with the favorable advection and divergence.
    9  Characteristics of a Persistent Frontal Fog Event in LowLatitude Mountain Area
    Yang Jing Wang Chao Peng Fang Li Dengwen
    2011, 39(4):445-452.
    [Abstract](1539) [HTML](0) [PDF 5.86 M](1456)
    Abstract:
    An analysis is made of a frontal fog event occurred in the lowlatitude mountainous area in Guizhou Province between 21 and 22 February 2008 by using conventional observation and NCEP/NCAR reanalysis data. The results show that the frontal fog occurred under special weather. The key weather systems for frontal fog formation include: the strong southwest air current at 500 hPa, the lowlevel southwest jet, and the decreasing quasistationary front. The fog lasted from evening to next morning, and the large area of frontal fog appeared before and after the thin quasistationary front. There was inverse humidity near the front zone, little rainfall and frontal inversion over Guizhou during the development and progression of the fog. The forming of the frontal fog in Guizhou was closely related to the quasistationary front, and the special mountain terrain led to the maintenance of the frontal fog.
    10  Mesoscale Diagnosis Analysis of a Regional Heavy Rain Case
    Li Qiang Wang Zhong Bai Yingying Du Qin
    2011, 39(4):453-461.
    [Abstract](1657) [HTML](0) [PDF 8.06 M](1642)
    Abstract:
    Using the data of precipitation observation, FY2C, realtime radiosonde sounding, and NECP/NCAR reanalysis, the evolution characteristics of key circulation systems, vapor transmission characteristics, moist potential vorticity (MPV), and vertical helicity (VH) of the regional heavy rain event in Sichuan Province and Chongqing from 2 to 5 August 2009 are analyzed diagnostically. The atmospheric circulation background of the heavy rainfall includes the eastward high trough coupled the southwestern low vortex, the dynamic blocking of Typhoon Swan maintaining over Sichuan Province and Chongqing, the southward invasion of cold air joined with the warm and wet vapor from the southwest jet, the formation of a clear cyclonic convergence, leading to the continuous generation and development of smallscale convective systems, and the favorable conditions for water vapor transport maintained in the precipitation process. The MPV was highly indicative for the area of the rainfall in the rainfall process. Due to the largescale descending air above the negative MPV center, the tilt degree of strong updraft, and the locations and intensities of the maximum frontogenesis forcing in the heavy rainfall, the strong precipitation area (Chongqing West) was located in the warm side of the negative center (Sichuan Basin) of MPV. The VH evolution is closely related with the heavy rain. The heavy precipitation occurs (weakens or ends) when VH contours becomes dense (sparse), and the appearance of heavy precipitation accompanies usually the upperlevel (lowerlevel) positive (negative) VH coupling.
    11  Evaluation of Difference between Automatic and Manual Observation for National Base Meteorological Stations
    Zhao Yufei Zhou Zijiang Zhang Qiang
    2011, 39(4):462-467.
    [Abstract](1439) [HTML](0) [PDF 5.12 M](1504)
    Abstract:
    An analysis is made of the differences between automatic and manual daily mean meteorological measurements (24 times per day and 4 times per day, respectively), and the ttest method is used to determine whether there is distinct difference between the means of two samples. The analysis of differences between 24timesperday and 4timesperday observations show that there is remarkable deference in relative humidity for about half stations, and there is remarkable deference in daily temperature, pressure and 2min wind speed at a confidence level of 005 for 15%, 0 and 69% of stations, respectively. Moreover, there are evident local characteristics in temperature and pressure differences. The analysis of differences between 24timesperday automatic observation and 24timesperday manual observation indicates that there is remarkable deference in daily mean temperature and pressure for 15%, 0 and 6.9% of stations, respectively, and in relative humidity and 2min wind speed for 762% and 787% of stations, respectively. It is obvious that the impact of two kinds of observation instruments is universal and prominent
    12  Comparison between Instrumental and Visual Measurements of Visibility in Urban Area of Central Liaoning Province
    Zhao Hujia Ma Yanjun
    2011, 39(4):468-472.
    [Abstract](1492) [HTML](0) [PDF 3.75 M](1493)
    Abstract:
    Using the instrumental and visual visibility data from May 2009 to November 2009 from Anshan, Shenyang, Benxi, and Fushun, which are all situated in the urban area of the central Liaoning Province, a detailed statistic analysis is made of the differences between two visibility measurements, in accordance with weather elements and weather phenomena. The results indicate that under the weather condition that there was obstruction to vision, the differences between instrumental and visual visibilities were relatively lower; the more the total cloud cover, the smaller the difference between two observations; the concentration of PM10 was negatively correlated with visibility, and its effect on the visual visibility was greater than that on the instrumental visibility; when the visual visibility was within the range of 1 km to 10 km, the difference between the instrumental and visual visibility measurements was the least; the average absolute errors of both visual instrumental measurements tended to decrease with the decreasing visibility.
    13  Application of Advanced Orbiting System in FY3 Meteorological Satellite
    Cui Peng Jia Shuze Wang Sujuan
    2011, 39(4):473-476.
    [Abstract](1438) [HTML](0) [PDF 3.95 M](1748)
    Abstract:
    In order to meet the needs of large capacity, highspeed, and multipayload data transfer, the data transfer system of the FY3 Meteorological Satellite adopts AOS (Advanced Orbiting System) standards recommended by CCSDS (Consultative Committee for Space Data Systems). Based on the concept of virtual channels, the multiplexing and bitstream services are provided to different types of payload data. The application results show that the two types of services meet not only the requirements of multiple highspeed transfer rates, but also the requirements of multipayload data transfer with different amount and formats. Based on the AOS protocol, the transfer frame format and the coding mode of FY3 are introduced.
    14  Key Technology of Remote Supervising System for Automatic Weather Stations Network
    Zhou Qinqiang Li Yuanhong Li Jianyong Lu Xueqin
    2011, 39(4):477-482.
    [Abstract](1602) [HTML](0) [PDF 4.48 M](1527)
    Abstract:
    Artificial maintenance of the automatic weather station (AWS) network is of great importance but needs a large amount of hard and timeconsuming work. The operational principles and the architecture of the AWS network, with observing data being collected by GPRS, are introduced. Based on this, the selfmaintenance procedures for the realization of AWS network updating and remote controlling are discussed in detail emphatically, and the judgment of sensor status from realtime observing data, the automatic extraction of fault information, and the automatic transmitting of short messages are described. It is indicated that the remote realtime supervision of working status and the automaintenance of the AWS network are satisfactorily realized, and the requirements of AWS network maintenance are met, with the network capacity becoming increased greatly.
    15  Timely Issue of Data on Public Weather Service Web Site
    He Xianfeng Jiang Lijuan Lei Shengkai Yu Huabin Luo Yongkang
    2011, 39(4):483-488.
    [Abstract](1917) [HTML](0) [PDF 5.23 M](1668)
    Abstract:
    Focused on the web construction of a content management system, the acquisition, processing,and releasing of surface meteorological observation data for public weather service are introduced. The data layer is the key part of the system, in which the acquired information is processed in aspects of quality control and statistical analysis. The hourly data recoding and storing into the database are conducted while the sequentially updated statistical results for daily/tenday/month/year reports are calculated. Through the timesequence analysis and the 2D GIS graphic analysis, the processed information is visualized and can be inquired by public with different demands. In application, the system works efficiently with the data from 2566 meteorological stations in China and provides services for several public portals.
    16  Deployment for Improving Database Application with Autotools
    Liu Yuanyuan
    2011, 39(4):489-493.
    [Abstract](1480) [HTML](0) [PDF 3.89 M](1488)
    Abstract:
    The GNU build system, also known as Autotools, is a suite of programming tools designed to assist in making sourcecode packages portable to many Unixlike systems, which can not only reduce the difficulty in developing transplantable software, but also simplify software compilationThe deployment and improvement of the databaserelated software by using Autotools are described Two tools of Autotools, Auotconf and Automake, are discussed emphatically from the viewpoint of the developer, and the detailed application method is introduced Autotools can further improve and popularize the application of databases, and can be used in other meteorologicalrelated software for releasing and sharing software packages on the Linux/Unix platform
    17  Construction of Remote Network Management Platform Based on Interactive Voice Response
    Mao Jian Zhou Liangnu
    2011, 39(4):494-497.
    [Abstract](1436) [HTML](0) [PDF 3.21 M](1533)
    Abstract:
    Based on the IVR (Interactive Voice Response)technology, a remote network management platform is established,with which the voice processing and remote listing of network events can be realized. By using this system, network administrators can keep up with the running status of the network anytime with a fixedline or mobile phone, thereby manage the network effectively. At the aspect of implementation, technologies,such as the Visual C++ integrated development environment, multithreading mechanism, and ADO database acces,are adopted. The system is characterized with the real time,easy operating, and low cost, and the practical applications shows that the system works satisfactorily.
    18  High Reliability Design and Construction of Communication Network at Citylevel Meteorological Services
    Zhao Yong Zhao Shufang
    2011, 39(4):498-501.
    [Abstract](1391) [HTML](0) [PDF 3.42 M](1602)
    Abstract:
    The reliability of a communication network influences directly the efficiency and quality of modernized meteorological service, and thus the Zaozhuang Weather Service put great emphasis on the high reliability design and construction of its communication network A introduction is made to the topological structure of the backbone network, the selection of city/countylevel links, the deployment of network facilities, the routing selection and planning of kernel switches, and the design and construction of high reliability redundancy for the communication network The communication networks of citylevel meteorological services play an importance role in public service and national disaster prevention and mitigation, and thus it is necessary and urgent to strengthen the high reliability design and construction of communication networks at citylevel meteorological services.
    19  Construction of DecisionMaking and Command System for Ground Weather Modification
    Wang Yilin Zhang Xinhua Jia Bin Wang Hualing Yu Jinyuan
    2011, 39(4):502-506.
    [Abstract](1704) [HTML](0) [PDF 4.73 M](1543)
    Abstract:
    In order to enhance the research and development of ground weather modification decisionmaking and command systems, the responsibilities and operation procedures of weather modification offices at various levels are discussed. Under the system that the surface weather modification operations are commanded mainly by citylevel weather modification offices, the major tasks of the provinciallevel weather modification offices are to make potential forecast and operation early warning. In the citylevel weather modification decisionmaking and command system, operations are based on the combined use of GIS, radar and other operation location data, with emphases on the operation indexes and the calculated operation parameters of artillery and rocket range, using GPRS to realize communication between the command center to operating points. The main responsibilities of countylevel weather modification offices are to monitor operations, make reports on operations and disasters to the city office, as well as command operations sometimes, and deal with some management affairs. The scheme can improve the reasonability and transmitting speeds of operation instructions,and can be put into operation.
    20  Trends of Water Quality Variation in Miyun Reservoir and Drainage Area of Baihe River for Precipitation Enhancement
    Zhao Xifang Zhang Qiang Zhao Shuyang Zhou Wei
    2011, 39(4):507-512.
    [Abstract](1173) [HTML](0) [PDF 4.65 M](1477)
    Abstract:
    The water quality of Miyun Reservoir and the drainage area of Baihe River, where precipitation enhancement was conducted, was monitored from 2006 to 2009. The results show that the annual mean pH difference at the two monitoring points was not pronounced; the highest pH was in spring, relative higher in autumn and summer, and the lowest in winter; the downward trend of pH variation at Miyun Reservoir was more evident than that at Baihe River. The effects of reservoir storage capacity and precipitation on pH are analyzed. The results indicate that from May to September the pH decreased with the increasing of precipitation, while from October to next April there was negative correlation between pH and precipitation; the influence of precipitation on annual pH variation is more obvious than that of the reservoir storage capacity. The chemical compositions in the reservoir (except K) were lower than those in the Baihe River. Ca concentration was the highest, followed by SO2-4, and the total concentration of alkali metals (Ca, Mg, Na, K) was much higher than that of anions (SO2-4,Cl-,No-3,F-). The concentrations of both Alkali metals and anions in winter and spring were higher than those in summer and autumn, with the maximum value in winter. The trend of reservoir anion interannual variation was not pronounced, and alkali metal variation showed a downward trend. The interannual Ag variation showed an increasing trend, and the trend in Baihe River was slightly obvious than that in Miyun Reservoir.
    21  Case Study of PBL Characteristics before and after Late Frost in Dali
    Xu Anlun Yang Yanjun Sun Jihua Liu Jinsong Li Wanhu
    2011, 39(4):513-519.
    [Abstract](1544) [HTML](0) [PDF 5.45 M](1525)
    Abstract:
    By means of the observational data of the planetary boundary layer observation system in the Dali national climate observatory, the late frost event occurred on 14 March 2009 in Dali is analyzed. The main results indicate: (1) The late frost injury occurred after rainfall and warmer weather, resulted from upperlevel cold advection and radiation cooling at night. (2) Before the frost, the meteorological elements showed significant changes due to the near surface layer affected by cold air. The main variation features during the day include high atmospheric transparency, cloudless sky, small wind speed, high air pressure, low air humidity, strong solar radiation on the surface, more surface heat storage, and higher temperature and maximum time delay. The latent heat flux played a dominant role in heat transferring. After sunset, the surface heat began to release, and the released heat was more than the absorbed during the day. Watervapor content and longwave radiation were stable, and air temperature decreased rapidly, and there appeared condensation phenomenon near the ground.
    22  Characteristics of Tornadoes around a Nuclear Power Staion in Hubei
    Ma Deli Chen Zhenghong Jin Ning Guo Qu
    2011, 39(4):520-524.
    [Abstract](1588) [HTML](0) [PDF 4.12 M](1487)
    Abstract:
    The characteristics of tornado events around the Xishui nuclear power plant of Hubei Province from 1964 to 2007 are analyzed based on the data from the area of 300 km×300 km around the nuclear power plant in the ways such as meteorological station records, climate impact assessment reports, etc. The results indicate that: there was apparent temporal distribution in those tornado events, such as daily, monthly, and decadal scale variation. The tornadoes concentrated mostly in spring and summer, especially in July, and occurred frequently from midday to early evening, especially at afternoon; however, there was seldom tornado occurred in autumn and winter. The average lasting time for all tornadoes is 27 min. During the past 44 years, tornadoes appeared most frequently in the first seven years of the 21st century. The wind speed grade is mostly 10 on the Beaufort scale, concentrated around 12. The most frequent moving direction of the tornadoes is from west to east, and the average affected width is 120 km, and the average affected length is 2166 km. The most severe tornadoinduced disaster is that induced by the extremely strong wind, which mostly accompanies hailstones, heavy rainfall, and lighting strikes.
    23  Effect of Winds on Track Racing and Other Outdoor Sport Events
    Zhao Yujie Yu Fengying Zhang Wenqin
    2011, 39(4):525-528.
    [Abstract](1325) [HTML](0) [PDF 3.53 M](1553)
    Abstract:
    The 10 min wind data from two automatic meteorological stations at the Olympic RowingCanoeing Park in Rizhao are used to determine the favorable track under different wind conditions Research results show that when the wind speed is less than 3 m/s, there is little effect on the choice of tracks; when the wind speed is higher than 3 m/s, the water track near the windward side maybe become favorable; when the wind speed is higher than 6 m/s and stability, the flatwater sport events cannot be hold The results can be used as a basis for referee groups to choose the favorable water track

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