Abstract:The convective cloud system on 22—23 July 2002 in Yichang region is simulated with MM5 model. The results from MM5 are then used as the input to a 3D microwave radiative transfer model that calculated the upwelling radiance received by the radiometer aboard the satellite. It is found that the structure of the convective cloud has a strong influence on the upwelling microwave radiation.

Abstract:With the nonhydrostatic mesoscale model(MM5V3),the evolution of typhoon Winnie after landfall is simulated.Verified against observations, the synoptic-scale circulation, height field, temperature field and precipitation are successfully reappeared. The diagnostic analysis in three aspects (the vapor conditions, the dynamic conditions and the vertical layer condition) is made. Finally, the mechanism of Liaoning extremely heavy rain is discussed.

Abstract:The characteristics of moist potential vorticity are analyzed during two heavy rainfall and two hail events in Northern Akesu. The results show that the stiff moist isentropes excite the development of moist slantwise vorticity and occurrence of heavy rainfall and hail. When MPV1<0 and MPV20 at 850hPa and MPV1>0 and MPV2<0 at 700hPa,sudden heavy rainfall probably happen. The order of magnitudes of MPV1 and MPV2 is equivalent. When hail occurred, there are MPV1>0 and MPV2<0 at 850hPa. Because of the difference of affective systems, there are different distributions for MPV1 and MPV2 at 700hPa, but reverse of MPV1 and MPV2 lead the development of slantwise vorticity.

Abstract:Synoptic characteristics associated with heavy rain brought by monsoon trough in the latter flood season of Guangdong from 1981 to 2002 are analyzed. The result indicates that most of the cases take place when the Pacific subtropical high is inclined to the east or in lower latitude than its normal position and are directly related with the westerly troughs or ITCZs. Most monsoon troughs lie over South China or it coastal water. The divergence areas at 200hPa level usually cover the whole Guangdong or the most part of it with the divergence center over the offshore area of South China. The advancing northward of the monsoon is mainly resulted from the development of the trough over Southwest China and South China and the northward movement of the tropical cyclones. The southerly flows on the western periphery of subtropical ridge sometimes could steer the monsoon northward too. As a result, the convection tends to move from the South China Sea and Beibuwan Gulf and its neighboring area toward Guangdong and with a daily variation.

Abstract:By mesoanalysis of a precipitation that occurred in the middle reaches of the Changjiang River, 8th Jul. in 2003, the formation and development of the event, its relation with the meso-microscale system are studied, it is emphasized that the low-level jet would cause favorable thermodynamic, moisture and dynamic conditions for the heavy rainfall in the middle reaches of the Changjiang River and that the mesoscale vortex formed in the left of the low-level jet would stimulate strong convective clouds and cause the heavy rain.

Abstract:The lightning warning technique with the detection data from the electric field meter on ground is based on the network observation of the electric field meters. Through detection of lightning number and intensity and polarity of electric filed on the ground produced by the electric charge center in the thunderstorms on automatic, continuous and real time mode, the lightning warning technique can provide the information about development of the charge center and position and movement of lightning activity in thunderstorm on the detection domain. With the combination of detection from Lightning location system, the lightning warning way give the more information for lightning detection and warning.

Abstract:Statistics about important feature parameters of the WSR-88D mesocyclone products is analyzed on the base of knowing the mesocyclone algorithm using the data of the last six years in Shanghai area. The basic features on mesoscale lifetime associated severe wind case are investigated. Then with the combination of severe wind records, the thresholds of adaptable parameters used mesocyclone algorithm in Shanghai are discussed and some adjustment schemes are suggested. Finally, a technical idea of forecasting local severe wind based on the mesocyclone products and other radar products are developed.

Abstract:Based on the volume scan data from the Doppler radar deployed in Yichang, and nearly simultaneous 10-minutes precipitation from 7 gauges distributed within 100 km centered radar's position, The real time characteristics of vertical profile of radar reflectivity (VPR) during the two time periods of regional intensive mixing precipitation in June and July in 2002 are analyzed. The VPRs clearly show the vertical structures of bright band of zero-temperature layer over the selected area, together with the vertical variations of the echoes, types of the precipitations, and physical status of the particles in the precipitation-cloud etc. The information from VPRs could be applied to analyze the types of the precipitation, and the evolution of particles in the cloud. There are agreements among the variations of VPRs detected at middle or low elevation angles in the continuous volume scans, echoes of PPI images exactly located over the gauge sites, and the 10-minutes amount of precipitation recorded by gauges, and these agreements are useful to estimate the amounts, types, and the evolutions of precipitation over the sites where the gauges are absent. Intensive convective precipitation usually occurred over the regions that VPRs detected together with no bright band, the big reflectivity factors, and the bigger reflectivity factors, the lower elevation angles.

Abstract:Based on daily summer rainfall data 1955—2000 at 91 stations in Northeast China and corresponding NCEP/NCAR water-vapor transportations, the regional characteristic of summer rainfall in Northeast China is analyzed, and further research of the features of abnormal water-vapor transportation of the flood years is carried out. The results show that the summer rainfall anomaly of Northeast China has obvious regional characters, there are six independent areas there. The study of the differences of water-vapor transportation between the flood years and the normal years indicates that the paths and key regions of the anomaly water-vapor transportation of one area are different completely to the other's.

Abstract:With the 3-D hailstorm numerical model, regional hail forecast in Hebei Province is made. Based on this, hail forecast of eleven cities in Hebei Province is made with MM5 mesoscale numerical model data. The results indicate that the method may play a referenced role in hail forecast.

Abstract:Based on precipitation data of 30 meteorological stations in the north wheat farming area from 1980 to 2004 from May to June, daily situation chart of 500hPa over Asia-Europe during the cloudy-rainy days and average geopotential height chart of 500hPa, the synoptic and climatically feature and the character of synoptic pattern of the continuous cloudy-rainy weather during the wheat harvest season in recent 25 years are analyzed. The relationship between the continuous cloudy-rainy process, the synoptic pattern and influencing system are studied. The result shows that block high with the cold vortex near the Baikal characterizes the synoptic pattern of continuous cloudy-rainy weather, in geostrophic wind filed of 500hPa, the wheat harvest area mainly locates in the boundary of south and north wind, during long cloudy-rainy days, south wind prevails in meridional wind field of 850hPa.

Abstract:Based on the synoptic theory, a heavy rain event in East China during 10—12, Oct. 2003 is studied. Results show that the monsoon cloud system generated in the Bay of Bengal and the spreading northeastward monsoon cluster and the upper-level jet cloud are the main synoptic systems. The interaction of low-level jet and upper-level jet attributes the good dynamic condition. After the analysis of the cloud images data and numerical products, it is found that the heavy precipitation is located in the area with characters both low-level strong convergence and strong vapor supplement.

Abstract:Based on the conventional meteorological data and WSR-98D radar data of Jinan, Shandong province, the upper air circulation, physics diagnostic field, the evolution of hourly precipitation with time, the base velocity and composite reflectivity, and so on are analyzed. The conclusions are as follows:(1) The stable upper air circulation at 500 hPa is the essential factor. (2) The convergence of vapor flux in the boundary layer is the source of water vapor. (3) The strong ascending motion is caused by “pumping” which is formed by strong convergence occurs in the north of the meso-scale cyclone and upper air divergence at high levels, (4) The meeting of two low-level jets makes the first hourly precipitation peak and the development intensively of meso-scale cyclone which makes the other hourly precipitation peak of Cangzhou station.

Abstract:The climatic charactors of Land and Sea breeze and it's influence on the local weather in Rizhao are analyzed by using the data of Juxian, Rizhao meteorological stations and the data of sea temperature. The results show that the variation of daily and seasonal land and sea breeze obviously affects the spatial and temporal distribution of the local temperature, precipitation, moisture, and cloud condition. The gradient wind often shows the fectures of sea breeze front and zonal coast front in the afternoon during stronger sea breeze and in the early morning during stronger land breeze. Low cloud and thunderstorm weather phenomena obvously increase,and the land and sea breeze and terrain obviously affect the precipitation distribution.

Abstract:TC precipitation prediction based on corresponding track-similar TC precipitation is one of operational TC precipitation forecasting methods.Typhoon Imbudo (0307),Krovanh (0312) and a Tropical Depression have similar tracks and both brought about heavy rainfall in Shenzhen,but their precipitation intensity have different features.The analysis shows that when typhoon Imbudo moved westward to the Jiangnan area, the Huanan area and the South China Sea were gradually controlled by the subtropical anticyclone. In this process the subtropical anticyclone becomes stronger and extends west. The easterly jet stream subsides, and the θ_se value is low. These factors are unsuitable to the development of Imbudo's precipitation cloud system.However, the South China Sea is controlled by a convergence zone before Typhoon Krovanh enters the area. In Krovanh's westward process, the subtropical anticyclone subsides, and the easterly jet stream becomes stronger. These factors are conducive to the development of the spiral band on the right front side of Krovanh. This is the reason that Krovanh brings more rainfall to Shenzhen than Imbudo though it is farther than the latter from the city.

Abstract:Based on the meteorological data and the Doppler radar data of Hefei, general circulation background, echo's development and evolution of the hail during 21 May 2004 in Chaohu, Anhui Province are analyzed. The results show that continued hail along the Chaohu lake in the short time period is closely related to its position between land and lake and caused by the superposition of mesosystem and the land and lake breeze.

Abstract:An investigation of low temperature of slopping field in Fuding, Fujian Province in winter, 2003—2004 is made. The results show that it is obvious that inversion layer is distributed in the mid-high altitudes of hilly area,where frozen damage could be avoid for the growth of Longan and Lychee.

Abstract:Based on the analysis of the MODIS data spectrum characteristics, and synthesis application of 3S technology, a work flow and quantified indexes to process the remote sensing data for monitoring the wheat straw burning in the field after harvest are suggested. These methods are successfully used to monitor this circumstance in Guanzhong Area in 2004.This work not only has significance for government to quickly and fully find out the situation of wheat straw burning, but also can improve the ability and efficiency of supervising this sort of happening.