Abstract:Based on the atmospheric radiation transmission theory,VIS(visible light)and IR(infrared)spectral characteristics of clouds and fog in the meteorological satellite remote-sensing images are studied in terms of spectral analysis method, which describes the spectrum response features and related index in the each channel of NOAA. According to the different cloud and fog top structure,the non-lambert property of cloud/fog reflecting visible light are analyzed.Based on the Rayleigh criterion,it is explained that visible light possesses more abilities of identifying fog and cloud when sun’s altitude is lower,indicating that fog has stronger directivity reflecting characteristics than cloud.When the satellite is placed in the mirror-reflecting-direction of cloud and fog,the brightness is stronger in fog area than in cloud area,otherwise darker.This shows that visible light has important role in identifying fog and cloud.By analyzing the different IR(infrared)spectral characteristics of cloud and fog layers,some indices of identifying cloud and fog and their classifications are given, showing that the channel combination method is of significance in identifying cloud and fog, and provides proofs for the classification of cloud and fog.By analyzing the time-variation spectrum of fog,the spectral characteristics of heavy fog in mature phase are obtained,which has vital meaning on judging the development and dissipation of heavy fog.

Abstract:It is a very complicated problem to estimate evapotranspiration(ET)over a large area natural surface.Based on the information of satellite remote sensing and geography,the natural surface is divided into 6 categories,and then the evapotranspiration for each category is calculated.By analyzing the satellite remote sensing and weather station data,the result of regional evapotranspiration over south Ningxia is given,and the result is also analyzed and verified.

Abstract:Based on the data of SST,rainfall in China,OLR and NCEP/NCAR 1958-1997 reanalysis data,the spatial/temporal variations of SSTA in the Kuroshio current region and its relation to summer precipitation in China have been analyzed by using the REOF method in this paper.Results show that there is an striking interdecadal change in SSTA,and the 4th-REOF spatial mode is a typical pattern for SSTA in the Kuroshio region.Correlation and composite analysis both show that there is more(less)rainfall in the Yangtze River in the positive(negative)anomaly year,especially in the Dongting Lake Region.

Abstract:The multiscale characteristics and period of summer precipitation in the Changjiang-Huaihe River valley have been analyzed by using the wavelet transformation.Through the wavelet transformation of Nino3 SSTA,indices of west Pacific subtropic high and Asian zonal circulation,the multiscale associations between them and rainfall in the Changjiang-Huaihe River valley have been investigated.The results suggest that precipitation of the Changjiang-Huaihe River valley has obvious interannual and interdecadal variation characters.The interannual peorids are found in 2～3, 5～6 and 7～8 year. The interdecadal periods are found in 12～13, 16～17 and 27 year.The characters of the south and north regions,as well as those of the middle and lower reaches of the Changjiang River,are different.The impact of Nino3 SSTA on rainfall in the Changjiang-Huaihe River valley is more significant than the impact of Asian zonal circulation.The association of the Nino3 SSTA,as well as the indices of western Pacific subtropic high,with rainfall in the Changjiang-Huaihe River valley is in-phase in some periods,but out-of-phase in other periods.

Abstract:Using the global land three months monthly data(PREC/L),the temporal-spatial features of secular variations of the global land rainfall of March to May during 1948-2001 are investigated.Results indicate that the global land rainfall of March to May mainly shows a negative trend feature especially in tropic Africa,the mid-west of Asia,the mid-east of China,the east of Russia,the Endebi land and Welks land of Antarctica.Seven regions experience an increase in precipitation,and they are the northwest of Russia,the southwest of America,the southwest of Canada,the south of South America,and the north of Canada etc.The trend variations of March to May averaged rainfall over 35 latitude zone are also examined,and the relation between global land seasonal rainfall and ENSO is discussed.Results show that the relation between seasonal rainfall and ENSO for spring is the most indistinctive among Spring,Summer and Autumn.

Abstract:29 representative stations in Northwest China are selected using EOF analysis,and the temporal and spatial characteristics of the interannual and interdecadal variations of 50-year spring and summer precipitation are analyzed.It is found that the tendency of precipitation in northwest China is positive to the west of 103°E longitude and negative to the east.And there are a quasi-three years periodic oscillation of precipitation and a sudden change in the spring precipitation in the middle 1980’s in northwest China.The above results indicate that the wet/dry phase of climate in northwest China is close related with the 500hPa height field and the location and intensity of subtropical high.

Abstract:Using the new generation mesoscale model of Weather Research and Forecast(WRF),with the high resolution grid points and the suitable physical schemes,the numerical simulation of the rain gush of the Jianghuai Meiyu front during 4th-5th July 2003 is carried out.Simulated results show that the rain gush and the genesis and development of the mesoscale system are well described,and the distribution,intensity and center location of the precipitation are successfully forecasted.The low-level jet,slantwise instability development,and the mesoscale low vortex system and the perturbation in the upper troposphere are analyzed,and it is found from the simulated results that the development of tilted vertical vorticity is the dynamical mechanism for the genesis and development of the low-level vortex.The sufficient moist available potential energy and latent heat release offer the material condition for this heavy rain event.

Abstract:The effect of the free mode on the trajectory of the solutions to a forced dissipative system is numerically researched.First,the free mode is obtained from observed atmosphere and a type of analytical free mode(ideal free mode)is designed;Secondly,using two kinds of the free modes as forcing fields respectively,and the 500hPa streamfunction field for July 1,1993 as the initial field, then the numerical experiments are run for 300 days by a forcing and dissipative global spectral model.Results indicate that when using the observed free mode for December 27-28,1992 as the forcing field,and α=γ=κ≥0.02,that is to say,when the forcing and dissipative coefficient is equivalent and great enough,the model atmosphere always approaches to the free mode as time evolves;when the forcing coefficient α=0.1 and the dissipative coefficient γ=0.02,the local quasi-biweekly oscillation appears in the extratropical latitude.When using the free mode of idealized atmosphere,dissipative coefficient 0.01,and forcing coefficient 0.0095≤α≤0.011, the period of oscillation has a positive correlation with the amplitude of the forcing coefficient.

Abstract:A diagnostic analysis is carried out to investigate the frequency modulation effect of El Nino and La Nina events on atmospheric low-frequency oscillations(LFO)in the mid-high latitudes.The power spectral analysis is performed for the daily Northern 500hPa height field data in the mid-high latitudes from 1950 to 1996.The results show that:(1)the intensity of low-frequency oscillation in winter is stronger than that in summer;(2)main periods of low-frequency oscillations show a shortening/lengthening tendency of low-frequency oscillation period during El Nino/La Nina event.The above results have the significant meaning to the research of the short-term climatic variation.

Abstract:The relationship is analyzed of January Kuroshio Region SSTA with summer precipitation in China and general circulation over East Asia.Results indicate that in the higher(lower)Kuroshio SSTA years,the blocking highs over the Ural mountains and Yakutsk become stronger(weaker),the low pressure trough between the two blocking highs turns deeper(shallower).At the same time,the Western Pacific subtropical high strengthens and stretches westwards(withdraws eastwards)and the Asian summer monsoon is obviously stronger(weaker).As a result,the confluence region of the cold/dry air from mid-high latitudes and the warm/wet air from the west of subtropical high locates at the mid-lower reaches of the Yangtze River(North China)and the summer rainfall in the above districts increases(decreases)correspondly.

Abstract:On the basis of the theories of baroclinic vorticity development,this paper discusses the conversion of horizontal vorticity into vertical vorticity in the large-scale motion of the atmosphere,and then the conversion terms is employed to describe the evolvement of the summer monsoon.We extract the terms of horizontal vorticity conversion from the equation of vorticity in the p coordinates,which is the main component of the baroclinic vector of large-scale atmosphere in the middle-upper troposphere,and then conclude that the conversion term is able to reach the same order with that of the local variation of the vertical vorticity when the large scale precipitation takes place in the summer monsoon period in China.By analyzing and calculating the GAME reanalysis data from April to August in 1998 in the monsoon region of Chinese mainland,we also found that the conversion term is important to the large-scale cyclone developing above the 600hPa,and also indicative of the onset of the South China Sea summer monsoon(SCSSM)and the development of Jianghuai meiyu.After the onset of SCSSM,the magnitude of the conversion term is correlated with the brisk and intermittence of the summer monsoon,and its changes also reflect the movement regularity of the West Pacific subtropical high(WPSH)over the mainland.Therefore it may be a convenient way to employ the baroclinic terms in researching influence of the moist weather processes on the short-medium range change of the WPSH and the atmospheric circulations.

Abstract:This paper introduces the principle of authority system strategy based on partition number and its application in role-based access control models. Using this principle,a structure-simple,scaleable and powerful user-privilege management system is easy to be established.It also presents a new conception that a natural number is partitioned according to a set. Finally,a sufficient condition that a natural number is partitioned exclusively in a narrow sense according to a finite set is given.

Abstract:Based on the characters of semi-tropical climate,topography,vegetation and the NOAA/AVHRR data in Guangxi,the split-window algorithms for retrieving the LST(land surface temperature)from satellite are analyzed and compared.The results suggest that the Becker&Li algorithm is suitable to retrieve the day-time LST in Guangxi.The clear-sky day-time-averaged LST in Guangxi is imaged by using the Becker&Li algorithm.We find out the approach of calculating annual mean LST by employing appropriate templets.For the cloudy region,the pixel values are substituted by the image data of same period and close time after being calculated. The calculation is based on the correlation of clear sky image with cloudy one.At last,the clear-sky day-time-averaged LST image of Guangxi is obtained.Analysis results indicate that the LST image made by the satellite remote sensing in this research is more extensive,more particular and clearer than that from the second agroclimatic regionalization in describing the distribution of thermal resource.LST is a more effective factor of thermal regionalization.

Abstract:In this paper,the nonlinear gravitational waves in a baroclinic atmosphere are studied.It is found by use of the WKB method that the interaction between two wave packets is governed by coupled nonlinear schrödinger equations and the immobile wave may occur.It is shown by numerical calculations that the waves amplify and the width of waves becomes narrow after the collision or chase of two solitary gravitational waves.The results indicate that the nonlinear interaction between the gravitational waves may be one of the causes for the outbreak of severe convective weather.

Abstract:O₃,NO_x concentrations and meteorological parameters in the urban atmospheric boundary layer in July 2002 were synchronously measured on a meteorological tower of 325m in Beijing.Analysis results show that the O₃ concentration differs remarkably at different levels,showing a distinct diurnal variation at the low level(120m） and maintaining a higher value at night at the higher level(280m） due to a weaker chemical depletion of O₃.In daytime the ozone pollution is most severe at 120m due to the joint effect of O₃ progemtor and local photochemistry reaction.The stability(Ri） is mostly neutral and the variations of Ri are small at lower levels;and it is frequently unstable,and its variation is large at higher levels.The O₃ fluxes transferred by turbulence show a single-peak change both in the lower and higher levels.

Abstract:In order to explore the applied value of the NCEP/NCAR reanalysis temperature data in studies on agricultural meteorology and environmental meteorology,this paper demonstrates the reliablity of the NCEP/NCAR data in context of the real ground surface observational data in Beijing,Nanjing,Guangzhou,Zhengzhou,Kunming,as well as Sanya.Using four kinds of interpolation methods,namely Cressman interpolation,parabolic interpolation,linear interpolation,parabolic and linear interpolation,the daily surface average temperatures of the NCEP/NCAR data are interpolated to the above six stations,and results from different interpolational methods are compared.Results show,for stations on a higher latitude north of 30°N,the bilinear interpolation method is better,but its accuracy is slightly lower.And for stations on a lower latitude south of 30°N,the Cressman interpolation is better,and more accurate.This may be related to that there are more missing data in the higher latitude.The paper proves that applying the interpolated temperature data to the analysis of the climatic adaptation of the seed production of two-line hybrid rice Pei’ai 64S in Tailand is feasible.

Abstract:Based on the LabVIEW of graphical program,this paper introduces the design and realization of the teacher instruction station of industrial processes simulation training system in detail.A system with this method had been applied in hydrogenation refining successfully.