Abstract:Huanan, Huazhong, Jianghuai and Long Delta mesoscale observation and application test bases of State Key Lab of Severe Weather have been set up base d on the above theories and techniques. Huanan base as a example, which is relat ed to how to implement and test new techniques, is introduced. It constructs a n ew style mesoscale synoptic platform for testing in the Huanan base. Based on setting up Huanan base, the Huazhong, Jianghuai and Long Delta bases will also b e constructed. How to enhance detecting, forecasting and warning capability of m esoscale severe weather will be investigated through testing running the four mesoscale synoptic operational platforms in the above four bases.

Abstract:For the sake of providing technical methods for precipitation modification, the structure and precipitation formation mechanism of precipitating convection clou ds of different types in summer are investigated. Based on 13933 mesoγ scale convection clouds observed by New Generation Weather Radar (CINRAD) in Hefei, th e life time, primary reflection rate, echo top height, echo thickness and vertic al integrated liquid water are statistically analyzed according to 5 kinds of sy noptic systems. The results about the 5 kinds of synoptic systems declared that the life time of convection clouds less than 1 hour accounted f or a major percentage of 90%-95% of the total sample, and the thickness of convective cell clouds are often 2-5km wit h maximum over 10km. Under controlling of subtropical high and its outer circle, the height of cloud top of 75% convective cells exceeded 0℃ layer. But under the influence of low troughs and southern branch trough, the height of most clou d top is below or near 0℃ layer. Top heights of convection cloud cells are main ly near or below 0℃ level when they are affected by the low trough of North Chi na, the low trough along coast and the south branch trough. These results are he lpful for the operation of artificial enhancement of rain.

Abstract:Abnormal changes of weather and climate have increasing influences on economic d evelopment and life of general public in China. It is very necessary to carry ou t an efficient meteorological risk assessment. Based on theory and methods of fu zzy maths and information diffusion，it integrates info of high impact weather e vents and dialing numbers of weather service phone (named 12121), the method of risk estimation probability of high impact weather events and meteorological att ention degrees of general public are given. Take Xi'an city as background，it ch ooses occurring days of five high impact weather events i. e, 〖JP2〗heat wave， thunderstorm， heavy shower，shower and scattered precipitation which are closely related to general public， and granted as risk resources, from 2004 to 2006 as statistical samples. The dia ling numbers of Xi'an weather service phone 12121 on the corresponding days are also gathered. Then，the risk estimation probabilities of high impact meteorolog ical events is estimated. Based on them and related demographic and telecommunic ation information，the meteorological attention degrees of general public at dif ferent grades are calculated. It is help for judging the influence, supplementin g the system of publicmeteorological services and improving the awareness of g eneral public to prevent meteorological-related risk as well.

Abstract:The extreme wind on 1113 April, 2006 in Hubei Province caused serious losses i n agriculture, electricity appliance and public accommodation of city. According to “Specification of Architectural Structure Load", the basic wind pressure an d the structural wind pressure are calculated by using the hourly wind speed dat a at the meteorological stations, and compared with historical data. The results show that the greatest (instantaneous) wind pressure at the height of 10m above the ground is 0.53kN·m-2,and the greatest structural pressure acting on 30m tower reaches 2.60kN·m-2，5 times more than the basic wind pressure, so it easily damage the towers, buildings and billboards.

Abstract:A dust weather process occurred in Henan Province during 11-13 April, 2006. By u sing NCEP reanalysis data (horizontal resolution 1°×1°) and the simultaneou s sounding, surface air observational records， a mesoscale numerical simulati on and diagnostic analysis applying dry intrusion theory was made for this proce ss. The results showed that the dry air intrusions obviously play a significant role in this process.The air of high potential vorticity and low humid slip peddown southward along with dense strips of equivalent potential temperatu re, which caused disturbances of potential vorticity and temperature in midlow level of troposphere. These disturbances led to strong cold advection southward and low pressure trough moving eastward and cold front southward, which affecte d together and triggered instable weather. Meanwhile with low level convergence and high level divergence, they caused this dust weather.

Abstract:All kinds of convective weather such as thunder storms, hail, torrential rain an d strong wind during warm season (from May to September) of recent 12 years in B eijing areas were statistically analyzed. It showed that the probability of conv ective weather is high. The climate probability of convection is 47.77% by conve ction days. The climate probabilities of strong wind, torrential rain and hai l are 27.29%, 10.84% and 6.29%,respectively. A majority of torrential rainoccurs from the second ten days of July to the first ten days of August. Howev er, hail commonly occurs in the second and the third ten days of June. The conve ctive weather often geographically occurs in northwest and northeast mountain ar eas and southwest mountain areas of Beijing. Whereas, it seldom occurs in center and southwest plain areas of Beijing. The torrential rain often occurs in northe ast mountain areas, central and southeast plain areas of Beijing, and it seldom occurs in northwest and southwest mountain areas. Mountain areas have more hail t han in the plain areas. Strong winds often occurs in northwest and northeast mou ntain areas. Torrential rain often occurs in the night. Hail of 76.72% occurs in the afternoon.

Abstract:By using the mesoscale numerical model MM5 V3.6, a successful simulati on is made for heavy rain event in the central and southern parts of Shandong Pr ovince on September 19-21, 2005. And the moist potential vorticity of the heavy rain is analyzed by using high resolution simulation result. The results indicat e that the stiff moist isentopes excite the development of moist slantwise vorti city and occurrence of heavy rain. A diagnosis of moisture potential vorticity i s made to show its temporal and spatial mesoscale characteristics. The results s how that the development of heavy rain is closely related to the temporal and sp atial variations of moisture potential vorticity. The heavy rain occurs in the i soline dense section of the negative MPV1 and positive MPV2, and the rain center lies in the convective instable section in the front of the negative MPV1 cente r at 850hPa.

Abstract:A typical rainstorm process in Haihe River Basin during 22nd24th July 2005 is synthetically studied with numerical model, conventional observations, multiple physical indexes, satellite data and radar data etc. To be summarized, the findings from the analysis are as follows: 1) the whole process was codeve loped by an upper trough, the warmmoist airflow on the edge of subtropical hig h and the lowpressure cloud system triggered by Typhoon Haitang during its col lapse phase. 2) The whole process is caused by some intensely developing meso and microscale convective cloud clusters which are triggered in the warm area by the updraft flow in front of cold airmass under some favor conditions such as high temperature and moisture and stratified instability. 3) The numerical mo deling forecasting has some indicative sense on the time and location of the hea vy rainfall and the cold advection in the middle of troposphere that intruded in toHaihe River Basin. Compared to the model developed by Germany, Japanese model a nd T213 model have shown predominance on the location forecasting of the heavy r ainfall in Haihe River Basin. However, the quantitative precipitation forecastin g from German model is most close to the observations. As a whole, these three m odels all have poor accuracy in the location of the west edge of the subtropical high. This fact is thought to be one of the reasons causing the forecasting err or in the temporal and spatial distribution of the heavy rainfall in Haihe River Basin.

Abstract:The variation trend, abrupt change and anomalous years of annual and seasonal me an soil temperature at shallow layers during the period of 1961－2005 in Lhasa w ere investigated by using modern statistical diagnostic methods such as linear t rend analysis, accumulated variance and signal noise ratio methods. The main res ults are as follows: (1)In terms of linear trend, theseasonal mean soil temperature at shallow layers displayed a significant increas ing trend in Lhasa in past 45 years, and it indicated an increase of (0.43～0.60 ℃)/10a which was maximum in spring, minimum in summer. Also, the annual mean so il temperature at shallow layers had a significant increasing trend, and the ris ing rates were (0.45～0.66℃) /10a, specifically at the depth of 40cm. Compared t o the air temperature, the rising range of soil temperature at 40cm was larger i n the same period. (2) The interdecadal variations of the annual and seasonal m ean soil temperature in the shallow layers had an obvious increasing tendency fr om 1960s to 1990s, especially in winter and spring. The mean soil temperat ure was colder from 1960s to the middle of 1980s, but it was warmer from the end of 1980s to 1990s. (3) The abrupt change of mean soil temperature at di fferent shallow layers occurred in autumn of 1986, and all the abrupt change of winter appeared in 1984.(4) Except for the annual mean soil temperature at 40cm was anomalously high in 1999, anomalous lower years occurred in the 1960s at the other shallow layers. Therefore, the increase of the soil temperat ure was mainly caused by the significant increase of air temperature.

Abstract:The characteristics of FY1D meteorological satellite are briefly int roduced. Based on the typical case of FY1D data, the spectral characteristics of fog in the different channels of FY1D are analyzed by using the histogram a nalysis method. The results indicate that the channel 1 and 4 are the represent ative channels of FY1D for the identification of fog. In the channel 1, fog is with uniform texture, smooth top, and clearcut boundary, and its albedo is ab out 20%～48%. In the channel 4, the brightness temperature of fog is 272～289K, and the difference value between the fog and the ground surface is no more than 6K.

Abstract:A method is put forward to recognize the fog based on the support vect or machine, according to the satellite remote sensing data. Firstly, the probabi lity statistics method is used to roughly judge the fog, according to the freque ncy of the fog areas appearing at different channels of FY1D satellite; second ly, based on the former judgment, the support vector machine is applied to judge the fog carefully; lastly, erosion and dilation techniques are used to optimize the result of the second procedure. From September to December in 2006, 65 over passes of FY1D satellite data including fog areas are analyzed, and the judged fog areas are found to correspond well to the experts' experience. And the resu lt shows that the combination of 1, 2, 4, 6, 7 and 10 channels is the best of ju dgment. The 5fold crossvalidation is 89.9849% and the TS score is74.04%. This method is also used to recognize the fog during other time, and fou nd that this method is excellent.

Abstract:Based on the daily precipitation data of flood season (from April to September) in 1960-2004 from 78 stations over the MidLower Reaches of Yangtze River, the extreme heavy precipitation threshold values for every station was firstly deter mined, then the extreme heavy precipitation event frequency in flood season was counted and their temporal and spatial characteristics are analyzed. The results show that the extreme heavy precipitation event f requency greatly affects the amount of total precipitation in flood season. The consistent anomaly distribution is the main spatial model of extreme heavy preci pitation event frequency over the MidLower Reaches of Yangtze River. The spati al distribution of extreme heavy precipitation event frequency can be divided in to five main regions. The maximum entropy spectral estimation analysis shows tha t 2-4 years period is significant in region I; the major notable cycle is basica lly the same in regions II and IV, including significant periods of 2-3 years an d 6.3 years; 14.7 years period of interdecadal variation is notable in region Ⅲ; 22 years period of interdecadal variation and 4-5 years period of inter annual variation are significant in region V. In all of the representative stat ions, Yueyang (region I) reveals a very significant growth trend, i.e. once per 10a; Nanyue (region II) and Nanjing (region IV) have a rather weak growth trend; the growth trend of Quzhou (region V) is weakest; and Hongjia (region III) show s a weak decline trend in the last 45 years.

Abstract:The interdecadal variation of summer monsoon rainfall in East Asia and its rel ationship with Pacific Decadal Oscillation (PDO) are investigated by using month ly precipitation reconstruction over global land, the monthly sea surface temper ature anomaly (SSTA) of Hadley Center for Climate Prediction and Research, and t he National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis dataset. It is revealed that both the interde cadal mode of the summer monsoon rainfall in East Asia and PDO occurred apparent interdecadal shift around 1976. Moreover, there exists close relation b etween summer monsoon rainfall and PDO on interdecadal time scale. PDO can gen erate anomalous atmospheric circulation in the lowlevel troposphere, which is homologous with the interdecadal variability of summer monsoon circulation in East Asia. It suggests that the external forcing of PDO in lower troposphere pos sibly exerts influences on the interdecadal variability of the East Asia summe r monsoon circulation, and finally leads to the interdecadal variability of th e summer monsoon rainfall in East Asia.

Abstract:To put Chinese automatic measurement of solid precipitation into practical effec t, and to know the precipitation measurement differences between Chinese standar d manual gauge and international reference instrument DIFR recommended by WMO, a comparison test of precipitation measurement was implemented at Daxigou, Changc hun and Tonghe in 2006. The catch efficiency of Chinese standard manual gauge in rain and in snow is given, respectively, including the different affections of wind on rain and snow measurements. The protection results against wind of manua l gauges in various installation ways are briefly analyzed. Based on catch effic iencies and some comparison observations, precipitation measurement capabilities are compared among seven types of automatic gauges. Then some bases and suggest ions are given for operational automatic precipitation record.

Abstract:The automatic quality control for real time data of automatic weather stations i s made by using the climatic extreme range check, internal consistency check, ti me consistency check and spatial consistency check. In order to reduce the numbe r of false check for meteorological element, a method which can check the sudden drop of temperature in single station is developed. Using the data of automatic weather stations in Hubei Province, the data are checked and the checked rate of error is 0.48‰. The data quality has been largely improved by using the abov ementioned method, especially spatial consistency check method based on the spatial interpolation. During the testing period, the quality control fo r an hour dada of 81 weather stations in Hubei Province can be completed within 2 minutes.

Abstract:Over the past ten years and more, the average temperature of Huantai s ituated in the northwest of Shandong Province is on the rise, and the temperatur e increased distinctly in winterhalfyear, which influences the growth of win ter wheat. Winter wheat commonly grow rapidly before winter time and over winter with green form, and its resistance to low te mperature is affected,it likely cau ses a natural hazard. We can strengthen resistance ability of winter wheat and d ecrease the possibility of its rapid growth by choosing a proper sown time to ad apt the temperature change. Now comparing three agriculture indicators (includin g the daily mean temperature from seeding to come out, accumulated temperature f rom seeding to growth cease, total accumulated temperature from seeding to harve st) with actual statistical result of temperature change over past ten years, we can find that as the temperature increases, the proper seeding time of winter w heat should be postpone compared to traditional seeding time.

Abstract:The encoder is a key part of servo system in CINRAD/SA radar, which contacts dig ital control unit with mechanism of the pedestal. While failure happens in azimu th loop, it will cause ananeose echo in products, and while fault happens in ele vation loop, it will cause INOP about radar system. Five faults about the encode r were analyzed. It discovered that the faults mainly come from the magnetizatio n voltage. When the temperature and humidity are too high in the antenna dome, partial parts will be degenerated. The problem will be throughout resolved after some measures are taken.