Abstract:By using the 40a monthly air temperature data during 1961-2000 at 60 stations in Jiangsu Province,the inter-decadal variabilities of winter (DJF) air temperature and their related backgrounds i.e. the features of the spatial distribution of atmospheric general circulation and sea surface temperature(SST) are studied.And the possible relationship between winter air temperature in Jiangsu Province and the global air temperature on the inerdecadal scale is also investigated.Results show that:1)the variations of winter air temperature at the 60 stations in Jiangsu are very consistent in space;2)In recent 40 years,the winter air temperature in Jiangsu shows,significant inter-decadal variation with the cold period in 1961-1985 and the warm period in 1986-1999;3)There are significant differences in atmospheric general circulation and SST between the cold and warm periods,and the inter-decadal variations of the winter air temperature and the East Asian winter monsoon(EAWM) are closely related to the inter-decadal background of SSTA;4)The anomaly of Jiangsu winter air temperature is inagreement with that of global air temperature on the interdecadal scale,and the evident increase in Jiangsu winter air temperature is completely consistent with the global warming.The interdecadal variation of Jiangsu winter air temperature can be regarded as the response of regional temperature to the global warming.

Abstract:Study shows that rain forecast is very sensitive to the initial humidity field.This paper aims at assimilating precipitable water(PW) data to improve the quality of model initial humidity fields,so as to improve the result of rain forecasting.At first,a regression method is applied to retrieve the PW,and then its effects on numerical simulation of torrential rain happened in June 18-19,1998 are assessed with comparasion experiments with and without the assimilation of retrieved PW.The results indicate that 1)the rain-belt position is closer to the observed after the assimilation of the PW data into the MM5,in addition the improvement in the intensity of torrential rainfall depends on cumulus parameterization schemes used;2)the effectiveness of precipitation simulation is enhanced because the improved initial humidity fields resolve the spin up problem in some sense;3)rain forecast is sensitive to cumulus parameterization schemes,and its essential to select corresponding cumulus parameterization scheme for different types of precitation processes when the initial humidity field is improved.

Abstract:Based on 1980-1997 T_BB data from the GMS of Japan and the NCEP/NCAR daily reanalysis data(1958-1997),an investigation is carried out of characteristics of convection activities over Sumatra area and its relationship with the South China Sea summer monsoon(SCSSM) onset.The results show that the onset of the SCSSM bears a close relation to the systematic moving of the convection center over Sumatra along the "land bridge" and Indo-China Peninsula from winter to summer.The sudden acceteration of convection shift affects directly the subsequent enhancement of the convection over Indo-China Peninsula area followed by the rupture of the subtropical high band in this region,leading to the SCSSM establishment.The convection exhibits a dipole distributive pattern between the SCS and Sumatra area before the SCSSM onset and the convection change shows an opposite trend between the SCS area and the south of Sumatra area.Before(during) the SCSSM sets up, the convection over the south of Sumatra area thrives (weakens).Therefore,we can regard the beginning date of the time period when the T_BB difference between the SCS and the south of Sumatra area≤5K and maintains for one pentad as an index of the SCSSM onset.

Abstract:By use of 1948-2000 monthly Northern Hemispheric sea level pressure data,the North Pacific oscillation index(I_NPO) and East Asian winter monsoon index(I_EAWM) are calculated.Results show that the winter I_NPO anomaly bears a close relation to the weather/climate of winter over the mainland of China.When a strong I_NPO occurs,the EAWM will become weaker,and China will experience an extensive high temperature,less rainfall in the middle-lower reach of the Yangtze River;and higher temperature and more rainfall in South China in winter.While a weak I_NPO occurs,EAWM will become stronger,and China will experience an extensive lower temperature and less rainfall in winter.It is also found that when the North Pacific oscillation is strong,the atmospheric circulation shows the weak WP pattern and strong EU teleconnection pattern,and vice versa.

Abstract:Aiming at the current condition of radar raw data,in the course of the construction of weather radar network,and the requirement of managing this kind of data in the meteorological operation development,teaching and scientific research work,this paper tries to design a raw data database management system of meteorological doppler radar for radar stations.The system is also a reference for the managing work of a regional radar net consisting of different radars,and the whole radar network in our country.The paper also describes the framework,contents and application of the system.Visual C⁺⁺ 6.0 as the programming language,Microsoft Access 2000 as the database was selected to realize the function of radar data appending,modification,deletion,query,data exportation,data transformation,data displaying,backuping of the database.

Abstract:The severe sandstorms encroaching on Beijing in the spring of 2000 were the result of drought over Beijing's upstream area.These make us pay more attentions to the deterioration of the climate environment.In this paper we investigate the possible causes of drought based on the NCEP/NCAR monthly data of volumetric soil water (SW) content at the surface layer(0～10cm depth) in the central Inner Mongolia region for the period 1950-1999. The results show that SW over the central Inner Mongolia region displays the significant seasonal variation,of a two-wave pattern. High SW occurs in the frozen season (December-March) and rainy season (August-September).Early summer and late fall are the dry season whose SW is very small;May-June is the driest period.The soil in north China has become drying since the middle 1960s with the severest drought period in the 1990s.The interdecadal variability of the period of 20～30a is one of the most important components in SW variations.Warming winters,especially in the 1970s and 1990s may be the most important cause for the drought of surface layer soil in north China.Artificial devastation of surface vegetation expedites the drought course because of increased surface moisture evaporation.Summer precipitation might be the secondary cause for the drought.Our results also demonstrate that the SW can be used as a valuable index for depicting drought.

Abstract:The Meiyu front rainstorm occurred in the period from 28th to 29th July,1998 in the Yangtze River's middle and lower reaches is dynamically diagnosed and numerically simulated using the MM5,and results indicate that the temperature and moisture disturbance in the lower level plays an important role in the development of convection and the generation of the rainstorm.The joint occurrence of low-level jet and wind shear is beneficial to the out-growth of the strong rainstorm.The structure of moist potential vorticity field in the rainstorm period differs greatly from those before and after the period.

Abstract:Using the rotated empirical orthogonal function (REOF) method,the normalized rainfall field during the May to July period in the Jianghuai Valley is divided objectively into the north and south regions.Based on this,the long-term trend and periodic variations of each region rainfall anomalies are analyzed.It is found that in the Jianghuai Valley,the peaks of precipitation anomalies in the south and north regions appear separately in June and July respectively.The trend of variations in the south region of the Jianghuai Valley is obvious in comparison with that in the north region,but the two regions have remarkable characteristics of interannual and interdecadal changes in the recent 50 years;There mainly exist 3-year interannual periods both in the south and north regions and a 21-year interdecadal period in the south region and a 15-year interdecadal period in the north region.Precipitation departures during the May to July period in the Jianghuai Valley is in phase with those in many areas of China in the wet and dry years,but the precipitation departure in the north region is always out of phase with that in south China.Further more,the rainfall anomaly in the Jianghuai Valley is directly influenced by the variations of the latitude of the subtropical high ridge and the intensity of the subtropical monsoon system.

Abstract:The impact of the assimilation of bogus vortex on the typhoon numerical simulation using the MM5 four-dimensional variational data assimilation system is studied in this paper.A series of 48 h simulations are conducted for typhoon Phanfone.The results show that: assimilation of the bogus vortex variables is more effective than the traditional method which implants a synthetic vortex into the background conditions.Simultaneous assimilation of the bogus wind, pressure, temperature and specific humidity data has less positive impact than that of the bogus pressure and any one of other variables.An initial vortex which has a clearer structure and is more consistent with the environment flow is obtained by assimilating the bogus specific humidity and pressure data.

Abstract:Based on the Arctic 1°×1° sea-ice area index,500hPa heights,sea surface pressure(SLP) and the China 160 Stations temperature data,the relationship between the interdecadal variation of sea-ice in Davis Strait and the atmospheric circulation is discussed by statistical analysis methods.It is founded that,in the past years,the sea-ice area in the Davis Strait increased and showed a remarkably interdecadal variation,which is close associated with the WA and EU teleconnection patterns,as well as with trends of Siberia High,and winter temperature in Northern China.There are remarkable differences in 500 hPa heights,SLP,stream fields before and after 1981,when the sea-ice area in Davis Strait abruptly changed.

Abstract:In terms of the East-Asian summer/winter monsoon indexs based on the updated sea level pressure(SLP) data,the relationships between the monsoon and indexes the precipitation in Shaanxi Province in the past 50 years are investigated.The results show that:the strong East-Asian winter monsoon means less rain in Shaanxi,while the strong East-Asian summer monsoon means plenty rainfall in the north,and less rainfall in the south of Shaanxi,and vice versa.Additionally,comparison of the Northern Hemispheric 500 hPa atmospheric circulations between strong and weak winter monsoon years,reveals the atmospheric circulation feature that results in the climate changes in Shaanxi Province.

Abstract:Based on the Boussinesq equation of mesoscale incompressibile atmospheric motion including surface heating,a set of analytical perturbation solutions is derived by using the integral transform method.Then the relationships among air turbulence,wind field and temperature field are discussed,the effects of perturbations of these fields induced by surface heating on air turbulence are analyzed preliminarily.

Abstract:By use of the monthly mean air temperature data at 160 stations in China during　1951-2000.12 stations are selected as representative stations in the south of South China. Based on the analysis of seasonal and interannual variations,the interannual and interdecadal variations of the air temperatures in the pre-flood period in the south of South China are emphatically studied in this paper.It is found that the air temperature in the pre-flood period in the south of South China are slightly colder before the 1990's,and get much warmer in the 1990's.The warming trend is obvious in the recent 10 years.The pre-flood period air temperature anomaly show the 2-year,4-year,5-year,12-year and 19-year periodic variations in the south of South China.The warming trend is similar with that in most areas of China.

Abstract:In the context of the temperature data at 160 stations(1951-01-1999-12) in China and the sea surface temperature(SST) data(1950-01-1998-12),the correlation coefficients between the summer temperature's standardization anomaly of Jiangnan and the global SST anomaly from previous January to this year's December are calculated.Results reveal that there is a higher correlation coefficient sea area in the middle of the tropical Atlantic ocean,its SST in previous October to this year's February significantly influences the next summer temperature anomaly in Southern China.

Abstract:In this paper the multiplier method and "potential well" methods are used to study a fourth order wave equation.It is proved that if its initial energy satisfies some conditions,then the problem has no global solution.

Abstract:The paper gives a comprehensive and systemical description on advances in the meteorological data assimilation,and presents an introduction to the theories and application of the main methods(especially the Adjoint method and Genetic Algorithm) in Data Assimilation.The GA (Genetic Algorithm)has opened a new way in solving the data assimilation problems.

Abstract:GPS meteorology,composed of ground-based and space-borne sounding,has been one of the important GPS applications so far.It is basically mature for ground based applications,and experiencing operational transition.As far as to space-borne GPS meteorology,there have been many launched GPS satellites and missions.In the future,GPS receiver for atmospheric occultation is one of payload for satellite in both NPOES and METOP.GPS meteorology will be part of satellite meteorology.The dataset of pressure,temperature,water vapor and electron content obtained by GPS sounding will be of great value for meteorological forecast,climate and space weather.