ISSN 1000-0526
CN 11-2282/P

Volume 33,Issue 11,2007 Table of Contents

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  • 1  The Ways to Enhance the Weather Forecast Skill
    Jiao Meiyan
    2007, 33(11):3-8. DOI: 10.7519/j.issn.1000-0526.2007.11.001
    [Abstract](698) [HTML](156) [PDF 381.88 K](1107)
    Abstract:
    A topic discussed is the ways to enhance the weather for ecasts skill. Many kinds of factors were related with the weather forecast skill . Scientifically, it is impossible to give the perfect weather forecast because of the existence of probabilities uncertainties. However, it is needed to improv e our skill on the weather forecast in order to meet the meteorological service needs better. By sharing the experience of advanced meteorological centers of th e world, the ways were explored to enhance the skill of weather forecast scienti fically and technically. Firstly, different advanced techniques and methods shou ld be developed and improved to support the weather forecast, not only the numer ical weather prediction model, but also the synoptic method, model interpretatio n scheme and dynamical analysis. The related scientific and technological effort s should be made on this area. Secondly, different specialized forecast, such as quantitative precipitation forecast, storm scale weather forecast and the typho on forecast, should be set up on the national level center to enhance the skill specially and to give strong guidance to the lower level weather forecast sectio n. Thirdly, a forecaster expert team should be brought up both by routine foreca st practice and scientific practice.
    2  Diagnosis of NorthwardDeflecting Track of Typhoon PrapiroonCaused b y the Environmental Flow Field and Typhoon Structure Variation
    Wu Naigeng Lin Liangxun Li Tianran Huang Zhong Chen Lisen
    2007, 33(11):9-15. DOI: 10.7519/j.issn.1000-0526.2007.11.002
    [Abstract](487) [HTML](81) [PDF 36.66 M](828)
    Abstract:
    The anomalous moving track of Typhoon Prapiroon is studied by using th e NCEP Global Data Assimilation System (GDAS) data and CIMSS microwave brightness tem perature data. The results show that the northward-deflecting track of Prapiroon is closely related to the midlatitude westerly trough, southwest monsoon and typhoon asymmetric structure itself. The meridional wind activities behind the w esterly trough and the directiron of maximum wind speed center have a certain in dication meaning for the moving direction of typhoon.
    3  The Analysis of Mesocyclone Product from the Doppler Weather Radar
    Fang Chong Zheng Yuanyuan
    2007, 33(11):16-20. DOI: 10.7519/j.issn.1000-0526.2007.11.003
    [Abstract](767) [HTML](82) [PDF 610.75 K](1032)
    Abstract:
    By using the Vmax mesocyclone products of new generation radar of Hefe i, the occurrence time, spatial distribution and a variety of characteristic val ues were statistically analyzed. It is discovered that the Vmax meso cyclone wh ich lasts more than three volume-scannings is well corresponds to the thundersto rm and gale. By analyzing the typical processes of gale, the relationship of th e variations in the height of echo base, echo top and severely shear with the oc currence of disaster weather was derived. It is valuable to the operator to mak e a forecast of thunderstorm and gale timely and accurately.
    4  Extraction of Divergence Information from Velocity PPI  Charts of Doppler Weather Radar
    Xu Fen Xia Wenmei Wu Lei Wu Linlin
    2007, 33(11):21-27. DOI: 10.7519/j.issn.1000-0526.2007.11.004
    [Abstract](637) [HTML](536) [PDF 31.33 M](818)
    Abstract:
    Based on divergence characteristics in weather radar velocity PPI cha rts, a divergence information extracting technique is suggested. The median filt ering method is used to eliminate noise contamination and one by one data symmet ry technique is used to reduce the errors because of echo lacking or range foldi ng. Considering the effect of raindrop descending speeds, fuzzy searching method is adopted for extracting wind speed determined divergence feature and histogra m is used for wind direction determined divergence feature. Comparative results show that abstracting method is effective and can well display the divergence in formation. There is a good corresponding relationship between atmospheric dynami cs features showed by the divergence and largescale precipitation process.
    5  Application of GroundBased Microwave Radiometer Detection to Precipitation Enhancement in the Upper of the Yellow River
    Wang Lijun Sun Anping Liu Caihong Zhao Kai
    2007, 33(11):28-33. DOI: 10.7519/j.issn.1000-0526.2007.11.005
    [Abstract](999) [HTML](91) [PDF 493.00 K](1012)
    Abstract:
    Qinghai from July to September in 2003, 2004. The cl oud water feature was analyzed by using the data from the microwave rad iometer, and an experiment of weather modification is preliminary conducted. Th e result indicated that there is a certain range of both Q and L under t he vario us atmospheric conditions, for which the retrieval model is effective. For the c umulonimbus case, there is an obvious fluctuation in both Q and L in adv ance of five hours of precipitation. Then, the convective cloud developed and Q and L ha d a sharp increase. Data comparison between Henan and Xi’an stations shows that Q and L were influenced by the terrain and vapor transportation. The fo rmer sta tion has a better potentiality of precipitation enhancement than t he later. The calculated threshold of precipitation has reference value for the operation of weather modification in the upper reaches of the Yellow River.
    6  The Forecast of the Snow Scenery for Tour Weather Service at Lushan Mountain
    Huang Shuilin Yang Xiaolan Wang Xiaobin Zhang Xiaopeng
    2007, 33(11):34-40. DOI: 10.7519/j.issn.1000-0526.2007.11.006
    [Abstract](739) [HTML](244) [PDF 724.91 K](962)
    Abstract:
    The snow scenery of Lushan Mountain is one of the famous meteorologica l landscap es at Lushan Mountain which is a place of interest in the south of Yangtze River in China. The weather characteristics of Lushan Mountain snow sc enery in aspects of esthetics and meteorology are introduced in view of tour wea ther service. The sustained time of snow scenery, the number of snowing and its annual distribution characteristics at different snowfalls in Lushan Mountain fo r 30 years are synthetically analyzed. Besides,the geographical distribution cha racteristics of meteorological landscapes of Lushan Mountain snow scenery is int roduced. In support of the modern meteorological operation forecasting system an d abundant meteorological information sharing resources on internet, some object ive analysis methods on snowfall and meteorological landscapes in Lushan Mountai n are summarized by references of numerical forecasting products with high time  efficiency in terms of tour meteorological forecasting characteristics of snow s cenery in Lushan Mountain.
    7  Analysis of a Snow Storm Caused by Reflux and Invert Trough
    Zhao Guixiang
    2007, 33(11):41-48. DOI: 10.7519/j.issn.1000-0526.2007.11.007
    [Abstract](794) [HTML](152) [PDF 1.34 M](1145)
    Abstract:
    A successive snow storm appeared on January 18 to 19, 2006 is analyzed. It shows that this case is different from the samples in the past:(1)The pol ar vortex at high level is stable and its intensity is large, polar front locate d at more north than the normal. The short wave trough split from the polar fron t overlapped with the south trough and made it develop and deepen. At that time, the snow storm occurred. (2) On the surface, reflux in the southeast and invert trough near the Hetao area jointed together and met with cold air from the nort h and caused the snow storm. (3)The deep moisture layer and the strong water vapor convergence together offered plentiful water for the snow storm. The center of the snow storm located at the south of two water vapor flux axes at low and midlevel separately. (4) The vertical allocation of the divergence at upper and convergence at low level,the strong ascending motion and dew point front continually lifting action triggered greatl y convective and uns table energy to release at the midlevel and it is an important mechanism of ca u sing successive snow storm. But LLJ and superLLJ can not only offer source of water vapor and transportation of energy but also make gravity wave develop unst ably, and that i s another important triggering mechanism of snow storm. (5) The snow storm appe ared at the right and before maximal advection center of the vortex at 500hPa. A fte r 12 hours, the intensity of the positive vortex advection center increased r apidly when there is an increasing rainfall.
    8  The Maintaining Mechanism of 0604 Severe Tropical Storm Bilis and It’s Influ ence on Yunnan Province
    Lu Yabin Pu Guiming Xie Mingen Zhang Tengfei
    2007, 33(11):49-57. DOI: 10.7519/j.issn.1000-0526.2007.11.008
    [Abstract](754) [HTML](162) [PDF 2.05 M](922)
    Abstract:
    MICAPS data was used to research the reasons of the path’s deflecting southwe stwards of 0604 severe tropical storm by synoptic and diagnosis analysis, and by the analysis on the storm rainfall caused by the severe tropical storm in Yunna n Province. The physical mechanism of the maintenance of the tropical storm’s s trength after landfall is also discussed. The result indicates that the main reason of the path’s deflecting southwestwards of Bilis w as the leading of northeast wind at the south of high which was formed by the me rging of continental high and the Huanghai subtropical high after its moving sou thwards and strengthening eastwards. Heavy precipitation caused by Bilis happene d at the center of water vapor convergence area which located in the northeast j et region on the front of inverted trough of tropical depression, and the locati on of the precipitation is corresponding better to the wet Q vector convergence area. During the period when the influence of tropical depression existed, the a tmosphere had wet neutral vertical moving structure and the situation was benefi cial for the growth of storm rainfall system. The interaction between Bilis and severe southwest jet for a long time after the landfall of Bilis was the main re ason for its maintenance. With the fading of southwest jet, the precipitation fi nished completely. The southwest monsoon cloud’s getting into the tropical depr ession strengthened the input of water vapor and energy, which was another impor tant reason that maintained the tropical depression and caused the heavy precipi tation. The South Asia high strengthened during active period of the tropical de pression, and the strengthening of divergence field on the upper level, the exis tence of lower level convergence and upper level divergence, and the maintenance of vertical positive vorticity which was related with southwest jet were benefi cial for the maintaining of the tropical depression and the movement tendency of the tropical depression to upper severe divergence area after its landfall.
    9  Analysis of Precipitation Characteristics in Hubei Province  and Their Influence on Flood/Drought in the Last 45 Years
    Liu Kequn Chen Zhenghong Zhang Liping Liu Anguo
    2007, 33(11):58-64. DOI: 10.7519/j.issn.1000-0526.2007.11.009
    [Abstract](771) [HTML](204) [PDF 1.20 M](1019)
    Abstract:
    The rainfall data, which were accumulated from the 72 meteorological sta tions of Hubei Province from 1960 to 2004, and the data on the droughtstricken and floodstricken area, which were published on the webpage from the Ministr y of Agriculture of the People’s Republic of China (zzys.agri.gov.cn), are anal yzed and discussed. The investigation is based on following several aspects of c limate, for example the climatic tendency, the skewness of drought and flood as well as the frequency and intensity of the heavy precipitation occurrence. It ca n be found that in the last 45 years the annual rainfall amounts have a strong i ncreasing trend in the east of Hubei Province, especially in the southeast of th e Jianghan Plain, while the annual rain days are decreasing. The increase of the rainfall amounts is mainly result from increasing of the heavy rain or rainst orm. At the same time the intensity and the frequency of durative heavy precip itation eventsincrease also in this region annually. The analysis on the relationship between the droughtstricken or floodstricken area and the skewness of drought or flo od indicates that climate disasters result mainly from unbalanced spatial and te mporal distribution of precipitation. Furthermore all these factors, such as the increase in rainfall amount and intensity of rainfall, the decrease in lake are a, the natural sinking of the Jianghan Plain, etc., quicken the intensity an d frequency of drought or flood, on which the local governments should focused.
    10  Forecasting Verification of GRAPES Model in the Reaches of Changjiang River
    Xu Shuangzhu Zhang Bing Shen Wei
    2007, 33(11):65-71. DOI: 10.7519/j.issn.1000-0526.2007.11.010
    [Abstract](804) [HTML](113) [PDF 2.32 M](936)
    Abstract:
    GRAPES(Global/Regional Assimilation and Prediction System) is a new general nu merical weather model in China. using GRAPES products and conventional observati on data 11 main precipitation courses that occurred in the reaches of the Changj iang River from 2005 to 2006 are checked, and the forecast evaluation of GRAPES model is given.
    11  Numerical Simulation and Risk Evaluation of  Rainfall Water Logging in Liuzhou City
    Zheng Chuanxin Mi Puqiang Chen Jianbing Liu Mei
    2007, 33(11):72-75. DOI: 10.7519/j.issn.1000-0526.2007.11.011
    [Abstract](544) [HTML](84) [PDF 366.62 K](876)
    Abstract:
    The water logging disasters caused by the different types of rain are simulated with the water logging simulation model. The risks caused by the wat e r logging are also primarily estimated. The results show that the water logging disasters are almost gradeⅠ or Ⅱ when the rainfall is below 100mm. When the rai nfall is above 100mm and 150mm the water logging disasters of grade Ⅲ reach 25% and 37%, res pectively. The absolute errors between water logging values and simulated values are within 20cm, but the absolute errors increase up with rainfall intensity. T he water logging disaster caused by the first heavy rain is more serious than the simulated result. But the case is quite the contrary that the heavy rain occurs after long and continuous fine weather, for example lasting 19 days. The above results can provide some references for expanding forecast and service field of urban disasters as well as risk estimation of water logging disaster.
    12  Study on the Extraction of Sugarcane Planting Areas from EOS/MODIS Data
    Tan Zongkun Wu Lianglin Ding Meihua Yang Xing Ou Zhaorong He Yan Kuang Zhaomin
    2007, 33(11):76-81. DOI: 10.7519/j.issn.1000-0526.2007.11.012
    [Abstract](1016) [HTML](163) [PDF 1.47 M](1136)
    Abstract:
    An automatic approach was presented to extract the sugarcane planting area for the mixed vegetation and hilly region in Guangxi province by using the moderate spatial and high temporal resolution MODIS data. The samples of a tra ining region were selected by GPS and the temporal variation curve of NDVI was w orked out. The maximum likelihood method was used to extract the information of sugarcane planting area and its spatial distribution through calculating the multiple phase MODISNDVI. The comparison of results from remote sensing image s with the investigations by GPS shows that the sugarcane planting area can be e xtracted from MODIS data, and the accuracy is more than 90%.
    13  Statistic Characteristic Analysis of Fog  in Southwest Shandong Province
    Zhang Zonghao Wang Yongqing
    2007, 33(11):82-86. DOI: 10.7519/j.issn.1000-0526.2007.11.013
    [Abstract](734) [HTML](142) [PDF 596.56 K](972)
    Abstract:
    By using the observation data of 9 stations in South w est Shandong Province from 1971 to 2000, the climatology and weather statistic characteristics of fog are analyzed.The result shows that this region is a highincidence area for fog, and the distribution features are that there are more fogs in the north tha n in the south. The seasonal and daily variation are obvious, the key generation per i od of fog is between 2:00 and 12:00 from Oct. to Feb. of the next year. There ar e two leading wind directions of NNW and SSE and a temperature window from -3 ℃ to 2℃ in southwest Shandong Province, when the fog frequency is the highes t. 4 typical weather conditions of fog for short range weather forecast are give n. It’s useful to fog forecast.
    14  Discussion on the Objective Classification Method for  Tenday Rainfall of Jilin Province
    Chen Changsheng Wang Huimin Mu Xiuxiang Wang Xiuqing
    2007, 33(11):87-92. DOI: 10.7519/j.issn.1000-0526.2007.11.014
    [Abstract](715) [HTML](97) [PDF 888.51 K](911)
    Abstract:
    Based on the current standard and method to classify the tenday rainfall of Jilin Province at present, a new method, which is based on the pro bability distribution function, is presented. In view of the nonnormal distrib u tion of tenday rainfall, Z index transformation is employed. The index can tran sform the nonnormal distribution data into the normal one. The classification r esult of rainfall is based on classifying the Z index. The results of the n ew method are more stable and more rational than those of the original method.
    15  Verification of the Mediumrange Forecast Efficiency of T213 and ECMWF and JA PAN Model from June to August 2007
    Li Yong
    2007, 33(11):93-100. DOI: 10.7519/j.issn.1000-0526.2007.11.015
    [Abstract](624) [HTML](106) [PDF 2.19 M](941)
    Abstract:
    Actually, the products of numerical forecast have been broad applied to weather forecast operation in China. In order to improve the ability to use the products of T213, ECMWF and Japan models, the performance of T213, ECMWF and Japan model s for 96h mediumrange forecasting during the period from June to August 2007 w as verified and compared in the paper. The results show that the three models have a good performance in aspect of predicting the largescale circulation evoluti on and adjustment in Asian middle and high latitudes. As a whole, ECMWF model is more classic in forecasting most weather systems compared with the T213 and Jap an mo dels. Especially, T213 model has a large error in predicting path and intensity of typhoon SEPAT, whereas ECMWF and Japan models are relatively accurate.
    16  Climatic Factors, Seasonal Distribution and Indications of Sea Mirage in Penglai
    Zhu Long
    2007, 33(11):101-106. DOI: 10.7519/j.issn.1000-0526.2007.11.016
    [Abstract](562) [HTML](935) [PDF 445.49 K](903)
    Abstract:
    Climatic factors, seasonal distribution and the indications of sea mirage were d iscussed, based on the 37 sea mirages that took place over 27 years on the North Sea in Penglai. Results indicated that sea mirage may take place in Penglai all the year round, with a high frequency from early May to early August, for this time period had the most suitable climatic conditions. Temperature differences i n the air and sea surface reaching 8.5℃, windforce reaching 2 to 4 on the Bea ufort scale, and high humidity were essential to the occurrences of sea mirage i n Penglai. Fine days after rain or snow, great tide range, and a sharp change in air temperature were the indications of sea mirage in Penglai.
    17  Hourly Electric Load Forecast Based on  Different Weather Type in Summer
    Zang Chuanhua Zhao Minfen Lu Zhaomin
    2007, 33(11):107-111. DOI: 10.7519/j.issn.1000-0526.2007.11.017
    [Abstract](543) [HTML](153) [PDF 480.30 K](1099)
    Abstract:
    Monthly forecast equations of daily average meteorology electric loads are obtained by using the electric loads and weather data from June to August i n 2004 and 2005. The feasibility that the daily variation of total loads is repl aced by daily variation of meteorology loads to forecast daily total loads is st udied. The weather types are divided into five kinds and the ratio of the hourly loads to the daily average loads is calculated for each kind. The hourly electr ic loads equal to the product of daily total loads multiplied by hourly ratio in the corresponding weather type. Testing forecast is made during 2006, the resu lts show that average relative errors of daily and hourly average electric load forecasts are 2.0% and 2.9%, respectively. The variation of daily electric load s with large fluctuation is well predicted.
    18  Early Warning and Prediction of Abrupt Geological  Hazards Based on Weather Forecast in Ningbo
    Zhu Longbiao He Caifen Chen Youli Cui Feijun Zhu Xiaoxi
    2007, 33(11):112-117. DOI: 10.7519/j.issn.1000-0526.2007.11.018
    [Abstract](799) [HTML](116) [PDF 51.57 M](3270)
    Abstract:
    The geological hazards can be induced by both manmade and natural fa c tors. Precipitation may be the most important factor under a certain geological structure and environmental conditions. The early warning and prediction system of abrupt geological hazard in Ningbo would be very efficient and feasible in th e operation, which is based on artificial neural network (ANN) and geographica l information system (GIS), combined with rainfall factor from surface mesoscale observation system and highprecision grid rainfall amount forecasted by WRF mo d el and relied on MICAPS to achieve quick subjective correction by forecasters.

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