Abstract:During the past few decades, observations from Doppler radars are widely used in diagnostic studies of convective systems, severe weather detection, and short-term forecasting. With the deployment of the NEXRAD network in China, there has been an increased interest in driving detailed meteorological information from single or multiple-Doppler observations. Methods to retrieve information from radar data and their application in numerical weather prediction are reviewed and discussed.

Abstract:The χ²test is performed on the data set of daily precipitation and temperature of Shanghai, Hangzhou and Nanjing stations in the Yangtze Delta. The results indicate that there is no correlation between ENSO and the annual precipitation, seasonal precipitation and annual maximum temperature (not reach the significance level of 90%). If the ENSO is categorized into 3 types however, the results indicate that the El Nino type Ⅰ leads to more precipitation than normal year, about 15.6% more than the normal year, with lower occurrence possibility of higher-temperature climatic conditions; the El Nino Ⅱ type leads to precipitation 20%-30% less than that of the normal year, with higher occurrence probability higher-temperature climatic conditions.

Abstract:Based on the five station data in middle and north Ningxia from 1961 to 2000, the relationship between temperature in last winter and precipitation and frequency of sandstorm are analyzed. The results shows that the frequency of sandstorm in spring is corresponded with precipitation in last year and low air-temperature in winter. In March and April, it is also corresponded with the Asia circulation index. Because of the difference of their surface and peoples activity at each station, the correlation is obviously different too. As for various stations, their different correlation between the sandstorm frequency and Asian circulation in spring maybe just due to their different locations and surface conditions.

Abstract:Using the two-way nested grid mesoscale model (MM5), a heavy rain event over the middle and the lower reaches of the Changjiang River on the last ten days of June in 1999 is simulated. It is shown that the MM5 model can successfully simulate the event. The slowly motion of the meso-β vortex is the basic cause for the event. The high-level atmosphere divergence and the low-level atmosphere convergence, the strong vertical motion, the low-level plenty vapor source and the releasing of the convective unstable energy are of the dynamical mechnism of the vortex and of the maintaining and growing of the rain.

Abstract:Based on the meteorological observation data of surface and solar radiation from 2001 to 2002 in Mohe, Heilongjiang Province, using the BATS1E model with 6h time step, the BATS land surface process was coupled with vegetation growth process. The relationship between the growth of the deciduous needle-leaf forest in cold-temperate zone and the climatic factors is analyzed. The results show that the relation for various time scales is different. The diurnal variation of NPP has closer relationship with the solar radiation and the daily NPP has some negative correlation with precipitation. The monthly NPP has apparently active correlation with monthly average air temperature.

Abstract:Base on the summer temperature from 80 observational stations of Northeast China and North Pacific sea surface temperature(SST) data from 1961 to 2002, the relationship between the SST of the preceding winter and the summer temperature in Northeast China is studied with the Singular Value Decomposition(SVD). The results show that the SST in preceding winter has a very close relationship with the summer temperature in Northeast China. The prediction method based on the SVD is developed. The predict-examination in the last years shows that the method has the ability of prediction and steady character.

Abstract:Based on the weather radar data of Chongqing Municipality from 1982 to 2003, a statistical analysis of the climatic characteristics of the radar echoes of the various types of the meso-scale severe convective weather, such as heavy rainfall, hail, thunderstorm. It shows that (1) the spatial-temporal distribution of the echoes of the events is uneven. (2) The vortex echo is the primary characteristic of the heavy rainfall events, which may be related to the terrain of the Sichuan Basin and the southwest vortex. (3) The hail echo is the main agglomeration. (4) The thunderstorm echo is characterized as striation and bow-shaped.

Abstract:Based on the data in recent 50 years, changing characteristics of typhoons in the northwest Pacific Ocean and landing at China are analyzed. At same time, a quantitative method of assessment to annual disaster caused by typhoon is developed over rural region on the basis of social economic data and losses.

Abstract:Monthly rainfall forecast is one of the short-term climate prediction operations, It is important for disaster prevention to improve the quality of forecast. By using statistic principles, some improvement on factors selection standard and factors pick-up from data have been made, to improve monthly rainfall forecast greatly.

Abstract:Observation data of AWS-city from May 2001 to March 2002 and AWS-milos500 from January to may 2003 have been respectively contrasted with synchro conventional observation data. The cause analysis of the observation difference is made from their difference in sensor pieces and detecting principle, observation time, weather condition etc. Statistics analysis of the temperature error of AWS-city shows that the error is related with the weather factors. Based on that, the correction equations are given. Statistical test and actual verification proved that it had a better effect. The analysis shows that the observation differences of the AWS ere in or a little over the allowed scope, even thought they had many faults. AWS are superior to man-observed station at the aspect of the unifying of observation time.

Abstract:Characteristics of winter temperature variations are analyzed with average temperature date from 1954 to 2002 in Guangdong Province.By using principal component of factor fields, the characteristics of spatial-temporal distributions of winter temperatures in Guangdong are mainly classified into four categories. For the last 49 years ,it is about 90% cases belong to the categories of cold or warm in the whole province. Linear trend of winter temperatures in Guangdong is warm up with 0.25℃ per 10 years, which is weaker than other parts of China.

Abstract:Based on the data of typhoon and precipitation and history weather maps from 1949 to 2000, statistical analysis of typhoon heavy rain in North China is made, it is found that lots of characteristic about typhoon of time-space distribution, landing area, moving route, seasonal feature and the interaction between typhoon and mid-latitude system. It shows that in 52 years, there are 51 heavy rainfall events resulting from typhoon, about 1 event a year. Most of them occurred in the summer (July and August). When typhoons made landing, or disappear, the locations were very regular, and the landing places were mostly in Fujian, Zhejiang. There is no typhoon landing between northern Jiangsu and southern Shandong where typhoon goes out mostly. When a typhoon is very strong, appears easily. On the other hand, when a typhoon is very weak, there would be little precipitation.

Abstract:Using the daily rainfall data of 109 stations from 1960 to 2001, the area rainfall over the Changjiang valley is calculated with Taison polygon method, and the change trend of area rainfall for this region is analyzed. The result shows that there is a slight increasing trend of the annual area rainfall in the region. The spatial distribution of the trend coefficient of heavy rain frequency and rainfall in the region are also discussed. At most stations, annual and summer (June-to-August) heavy rain frequency and heavy rainfall show to be increasing. However, the increasing tendency is significant at a few stations. The center of the significant increase lies in Jiangxi Province.

Abstract:Based on the daily rainfall data of 26 stations in 1961-2002 and the precipitation data of 10 stations in 1981-2001 in eastern Qinghai province, the climatic variation characteristics of rain day and rain intensity are analyzed. The result shows that the rain intensity is increasing with the decreasing of rain day and rainfall in summer season, the decreasing of rainfall in summer season is mainly associated with the decreasing of rain day, while the increasing of rainfall in winter season is due to the increasing of snow day and daily average rainfall. In recent 20 years, the maximum precipitation intensity in 10 minutes and an hour increases significantly. The frequency of heavy rainfall at nighttime in the 1990s is much more than that in the 1980s.

Abstract:An analysis of the echo characteristics and the cause of formation of a local heavy rainfall in Yueyang, Hunan Province is made with the Doppler radar data and other meteorological data. And the short-term forecast and service of the event are reviewed.

Abstract:Base on Shum an-Shapiro mesoscale filter, high-pass filter under the background of large-scale circulation and analysis of satellite image and radar echo, the heavy rain in the central Yunnan on June 17, 2003 is analyzed. It shows that the rain can be attributed to the southeast movement and the development of a tropical mesoscale cyclone. The invasion of surface cold air to the mesoscale depression leads to the development of convective activities and the tropical mesoscale cyclone. The tansportation of water vapor from the Bay of Bengal, the South China Sea and west Pacific Ocean in large-scale circulation provides the energy to the development and maintenance of the strong convection. The center of the surface mesoscale depression and the north of the shear line are indicative to the rainfall area.

Abstract:System monitoring is a critical part for real time database system management. It is important, yet it will cost much time and energy of the system operator. This necessitates an automatic monitoring system which will monitor and report the system operational status automatically. The design and implementation of a multi-threaded, agent-based RDBS monitoring system are introduced.