Abstract:In comparison with multispectral remote sensing,the characteristics of hyperspectral remote sening data are more channels,narrower bandwidth and larger amount of data.It is very important to make optimal band combination in numerous bands for false color synthesis according to specific application purpose for further management,analysis and information extraction of hyperspectral remote sensing dada.Taking the complex ground surface hyperspectral image near the Huangpujiang in Shanghai from an airborne Pushbroom Hyperspectral Imager(PHI)as an example,the information content,the correlation of different channels and spectral character of ground objects are analysed to extract the band subsets with vast scale information content,smaller correlation,larger spectral difference,and then the optimal band combination of hyperspectral image is determined by using methods of covariance matrix,optimal index and band index.

Abstract:Based on data integration technique,direct transmittance models for different temporal and spatial scales were established and the accuracy of different models was analyzed thoroughly.Using the DEM(digital elevation model) data of 1km×1km resolution as input and giving an all-sided consideration on factors influencing direct solar radiation(DSR),a distributed model for calculating DSR over rugged terrains was developed,and monthly DSR with the resolution of 1km×1km over the rugged terrains of China was generated.Results suggest that(1)the topographical factors have robust effect on the spatial distribution of DSR,particularly in winter and autumn when the sun elevation angle is lower;(2)the proposed model is proved to be able to treat volumes of data and is applicable to satellite image processing platform or GIS.

Abstract:A 3D baroclinc ocean model is used to model the ocean current around the Kuroshio area on the condition of successively anomalous East Asia winter monsoon,some significant results are obtained,and the influence of strong(weak) winter monsoon on sea surface height(SSH),sea surface temperature(SST) and sea current around the Kuroshio area is analyzed preliminarily.The results show that the strong winter monsoon will decrease the gradient of SSH,and change the characteristics of SST,which has influence on the sea current,especially in a shallow and closed sea area such as the South China sea.The strong winter monsoon supresses the development of the Kuroshio current,on the contrary,it strengthens the other two warm sea current systems,i.e. the Tsushima Warm Current and Yellow Sea Warm Current.

Abstract:Using the June and July maximum temperature data at 64 observational stations from 1961 to 2001,the Changjiang-Huaihe valley's maximum temperature field in the Mei-yu period is divided objectively into 3 subdivisions by using the rotated empirical orthogonal function(REOF) method.Based on this,the long-term trend of each subdivision maximum temperature in the Mei-yu period is analyzed.Results indicate that the maximum temperature fields in 3 subdivisions have distinct interdecadal change character in the recent 41 years,and there is obvious regional difference:the long-term trend of southeast subdivision's maximum temperature is not distinct,but that of north subdivision's and southwest subdivision's is markedly decreasing.The interannual(interdecadal) variance contribution and variation periods in 3 subdivisions exhibit remarkable diversity.

Abstract:Based on the U.K.global SST,NCEP/NCAR reanalysis data and 160 stations rainfall data in China,by using the composite and singular value decomposition(SVD) methods,the effect of the Indian Ocean Dipole(IOD) on East Asian atmospheric circulation and precipitation in 1951-2000 has been studied in the present article.Results show that the IOD anomaly results in anomalous atmospheric circulation,which affects the distribution of the rain belt during rainy seasons in China and the East Asian monsoon.When the IOD is positive(negative),the subtropical high is south(north),and west(east) of its mean position,and stronger(weaker) than normal;the East Asian monsoon is stronger(weaker);the summer rainfall is less(more) in the Yangtze River basin and more(less) in south China.

Abstract:In this paper,the datasets of HadCM2 and ECHAM4 are employed to analyze the trend of surface air temperature and precipitation changes over China in the 21st century under the transient scenarios of the equivalent CO₂ increase 1 percent per year（IS92a）in concentrations from 1990 onward.It is shown that the surface air temperature increments would reach 5-6℃ at the end of the 21stcentury relative to climate baseline（1961-1990）.Meanwhile the precipitation would also increase,though exists the great fluctuations compared with the surface air temperature.It is indicated that the precipitation would obviously increase in South China,over 0.9 mm/d and 0.6 mm/d anticipated by HadCM2 and ECHAM4,respectively.It is presented from the comparisons of the performances of HadCM2 and ECHAM4 that ECHAM4 overestimates the surface air temperature relative to HadCM2;while HadCM2 overestimates the precipitation.However,the overall trend of HadCM2 is similar with ECHAM4 anticipations.

Abstract:Any model merely simulates a approximate status of atmosphere.Considering that the model is traditionally supposed to be exact and only initial data fields are amended in Adjoint Assimilation System(AAS).In this paper,the MM5 Adjoint Assimilation System is used to correct MM5's terrain error.The experimental results of amending different initial terrain data indicate that:the MM5 AAS is able to retrieve the terrain field,whose resolution is matched with one of the initial meteorological element field and therefore well coordinated with the MM5 model.Thus a new way about how to widely use the assimilation system is offered in this paper.

Abstract:The Grey Level Co-occurrence Matrix(GLCM) approach was firstly used in this paper to extract the textural parameters,the intrinsic attribute of different types of clouds,from 100 satellite images of cloud cluster samples,and then,four texture parameters of cirrus,cumulus,cumulonimbus,stratus and cloudless areas were clustered by using the Mahalanobis distance as the comparability measure standard.In the experiment,textural features of the clouds,of the strong rainstorm in the period of July 4-5,2003 in the middle and lower reaches of the Changjiang River,and their relations with precipitation were analyzed.Results of the quadratic polynomial regression analysis show that the developing tendency of texture parameters is parallel with one of precipitation.These results are of practical significance for the diagnoses and numerical prediction of weather processes,especially of short-medium range rainstorm processes.

Abstract:The EVAD technique,which was presented by Srivastava,is often unsolvable because there usually exists sick matrix in practice.Thomas utilized the weighting function method to solve the problem.In this article,a modified Gram-Schmidt arithmetic(MGS) is introduced to solve the same problem.The atmospheric mean horizonal convergence in two examples is calculated using the two modified EVAD methods,the convergence obtained is then adjusted with the variational method,and the vertical velocity is computed in terms of the continuity equation.At last,various computed results are compared and analyzed.

Abstract:A new regional climate model RegCM3 has been used to simulate summer precipitation in May-August 1998 over Eastern China,and its capability of simulation for precipitation and large-scale circulation systems is investigated.The result shows that different convective schemes made large differences in the simulation of rainfall for different months and regions,the schemes of Kuo and Grell exhibited better performance than the scheme of BM;the RegCM3 could well reproduce the main features of monthly variation and spatial distribution of rainfall;it also well simulated the evolution of subtropical anticyclone ridge in the Western Pacific and two northword-propagating intraseasonal oscillations.Therefore we consider that the model can be applied to the study of summer precipitation simulation over Eastern China.

Abstract:Measurements of stratus cloud microphysical properties were carried out in Hebei Province in October 1990 and April 1991 using a aircraft PMS（Particle Measurement System）.The analysis results will be useful for studies on global climate change,satellite remote sensing and aircraft measurement.In this paper,the cloud micro-properties and vertical structure are preliminarily analyzed,and the relationship between aerosol and cloud droplets is also analyzed.The results show that,in the early 1990s,the cloud-droplet number concentration is 79.2cm^-3 and the liquid water content is about 0.03g·m^-3.The effective diameter for stratus cloud drops is around 11m and it varies vertically.There is a positive correlation between aerosol number concentrations below the cloud base and cloud droplets number concentrations.

Abstract:In the frame of the vortex self-organization dynamics the question of the interaction of binary vortices is investigated by using a numerical model and the differences and homogeneities of binary vortices interaction under the two types of conditions of weak enviromental fields and vortices swarm ambient flow are analyzed.It is shown that under the enviromental condition of vortices group the merger process of binary vortices happened in the case of weak enviromental fields no longer occurrs;and meanwhile,the introduction of vortices swarm might lead to the intensification of vortices.

Abstract:Based on the NCEP/NCAR monthly SLP reanalysis data,the interdecadal changes and propagating features of the Antarctic Circumpolar Wave(ACW) during 1952-1998 are studied in this paper by use of the first recovered field of the complex empirical orthogonal function(CEOF) expansion.The results show that the southeast Pacific is a key area for researching ACW.Then the activity index of ACWs over the southeast Pacific(EPAI) is defined.It is revealed that there is a close relation between the EPAI in autumn and the next summer rainfall over China.When the autumn EPAI appears an abnormally positive phase,namely while the positive SLP anomalies occurs over the southeast Pacific,the Australian high becomes stronger than normal in the next spring and summer.Furthermore,the enhancement of the cross-equatorial flow and the shift of the west Pacific subtropical high lead to the summer precipitation pattern of more rainfall in South China and less rainfall in the Changjiang-Huaihe valley in the next year,thus confirming that the ACW is a strong interannual variation signal for the abnormality of summer rainfall over China.

Abstract:The solar and infrared radiation over east China in summer troposphere were calculated using the MODTRAN3 model and the satellite TOVS data.Solar heating rate and infrared cooling rate were calculated and analyzed from the 43 samples at 12 stations at different latitudes on sunshine day.It is found from the analyses that in summer troposphere,the solar heating rate decreases with height,and its magnitude and change rate are correlated with latitude,zenith angle and atmospheric state.And meanwhile,the solar heating rate also varies diurnally.The infrared cooling rate reaches the minimum value in middle and upper troposphere,and its magnitude and change rate are correlated with latitude and atmospheric state.Results of this paper were compared with precious conclusions and reality,and it is found that the results realistically reflect the radiation heating state of the summer troposphere over east China,and therefore are reliable.

Abstract:By use of the NCEP/NCAR daily reanalysis sea level pressure data from 1948 to 2002 and monthly rainfall and air temperature of 160 stations in China,the spatial and temporal variations of the frequency and intensity of spring Northern Cyclones have been computed,and relationships between spring Northern Cyclones and the temperature and precipitation over China also analyzed.Results show that in spring Northern Cyclones have high frequencies and there are two distinct high value centers:one locates in the middle of Mongolia;the other in the north of northeast china.There are obvious interannual and interdecadal variations in spring Northern Cyclones frequencies and intensities.With the decadal climatic catastrophe in global scale,there was a abrupt change in both frequency and intensity in the mid-last of 1970s,i.e.the frequencies and intensities of Northern Cyclones decreased from 1980s to 1990s.The frequencies of spring Northern Cyclones mainly have important influence on rainfall and air temperature in the north of china.When the spring Northern Cyclones are active(inactive),the rainfall is less(more) in the most part of North china as well as the north of Sinkiang;and the temperature is higher(lower) in the north of Sinkiang,whereas the temperature is lower(higher) in part of Gansu,Ningxia,Shanxi and Neimeng.In spring,the frequency-descending and the intensity-weakening of Northern Cyclones from 1980s to 1990s are responsible for the reduction of frequencies of sandstorms in compansion to the 1970s.

Abstract:This paper discusses the construction and application of BP-type multilevel mapping model with dynamic learning rateηBased on the 2002 observed temperature data of Yuanjiang Meterorological Station in Hunan Province,daily mean temperature prediction is made by using a dynamic learning rate model,a fixed learning rate model and a stepwise regression model.Results suggest that the BP neural network model is superior to the regression model in predictions,and also swift in learning if the dynamic learning rate is adopted.

Abstract:Statistical features of the impact of the previous sea surface temperature anomalies(SSTA) on the main flood season(July to August) precipitation in the Liaoning Province are found in this paper based on a background analysis of the temporal variation of the precipitation.Results show that the precipitation has obvious inter-annual and inter-decadal decrease trends in the recent 44 years.There are 3~5-year inter-annual and 10~12-year inter-decadal periods as depicted with the wavelet analysis.Two key SSTA areas and their key time periods are found,one is the south Atlantic and the other is the western Pacific.By combination of the SSTA variations in the two sea areas,the main flood season precipitation anomaly in Liaoning Province might be better predicted.

Abstract:Analysis on the spring sandstorm trend since 1960s in Ningxia was conducted and results show there is an obvious interdecadal change in sandstorms,an abrupt change in spring sandstorm days in Ningxia occurred in the middle 1980s,and the sandstorm days were more frequent before,and obviously less after the middle 1980s.Analyses on long-range changes of circulation,sea surface temperature,gust days,average temperature indicate that the intensity and area of Northern Hemispheric polar vortex,Asia west wind index,SST in Nino3 area and spring gust days,average winter temperature,average temperature difference of winter and spring are correlated with the features of the interdecadal change of sandstorms,i.e.there was a jump in the middle of 1980s of many factors affecting the frequency of cold air activity.The frequency of cold air activity plays a key role in the formation of the trend of spring sandstorm.

Abstract:Based on the current situation and shortcoming of the e-government network in the process of security building,an integrated filter platform-WebFilter for identity authentication and access control was designed according to the requirement of e-government application security.The pattern of design,function,construction,key technology and implementation method for the platform are explained in this paper.A safe data access channel between user and application server is built,which provides a valid solution for other application security building based on the internet.

Abstract:There has been a substantial growth of road traffic over the years and consequently,of air pollution caused by the vehicular exhausts,which is now considered as one of the primary source of urban air pollution.So the research of vehicular exhaust dispersions can serve the road construction,vehicle control,monitor assessment and decrease of air pollution over road.A comprehensive overview of the road vehicular pollution dispersion models is presented in this paper.The emphasis is on the progress together with the existing limitations of various models including Gaussian models,numerical models and statistical models.Then the accuracy along with the suitability in various conditions are compared.Subsequently,the review specializes at the dispersion models of urban street canyons.It points the primary difficulty of current model research existing at the simulation of the flow in urban street canyon,at the same time,introduces the progress in the simulation.At last,several crucial barriers in developing vehicular pollution dispersion models are presented,and the possible solution ways are also given.