Abstract:In the context of the 1958-1997 NCEP/NCAR reanalyses,the south Asian high(SAH) is vertically divided into two components,barotropic and baroclinic circulations,whereupon the conversion features are addressed of the SAH during its seasonal variation.Evidence suggests that 1)in summer(winter),the SAH is dominant by the baroclinic(barotropic) component accounting for approximately 70% of the total contribution; 2) as time progresses from winter to summer,accompanied by the barotropic SAH evolving into its baroclinic analog,the SAH moves under the guidance of its baroclinic component circulation,suggesting that the baroclinic component circulation precedes the system itself in variation; 3) the reversal happens when it goes from summer to winter,with the SAH displacement under the steering of its barotropic component circulation.

Abstract:The catastrophe of subtropical high ridge position in 1979 is examed with the aid of wavelet analysis test,the result is quite the same with that by Mann Kendall test; Further analyses show that the catastrophe of East Asia and the Global atmosphere general circulations also takes place in 1979, meanwhile China rain pattern changes from the central drought two side flood to the central flood two side drought.

Abstract:Based on the T BB data from Japanese GMS satellite and the GPCP rainfall, movable t test technique is employed to reveal the climatological features of convection onset and advancing over the Asian tropical region during the spring to summer season.Results show that the convection occurs first in the middle Indo China peninsula in mid April,and then slowly advances eastward,expanding to the whole South China Sea in 28th pentad.The convection experiences such a strongly sbrupt change over Asian tropical area during the spring to summer season that the movable t test of the T BB and rainfall exceeds the statistical significance at 0.01 level.It is also found that each subregion has its own center of convection onset,with the northern South China Sea,northeastern Bay of Bengal and northeastern India being the most significant regions.

Abstract:Based on the Northern Hemispheric 500hPa height and rainfall in China,study is performed of relations of the East Asia general circulation and rainfall anomalies in the middle lower reaches of the Yangtze river in terms of EOF,composites and SVD analyses.Results suggest that the EAP index has a close relartion with the system configuration of 500 hPa height field and the summer rainfall in the middle lower reaches of the Yangtze river.That is to say,in the flood(higher EAP index) years the general circulation at 500hPa displays a typical EAP pattern with a strong West Pacific subtropic high south of 30°N,while in the drought(lower EAP index) year,the West Pacific subtropic high is weak and lies north of 30 °N.The EAP index shows biennial,quasi 3 and quasi 6 year,and interdecadal variations,which also reflect well the interannual and interdecadal trends of flood/drought and 500 hPa height pattern over the middle lower reachds of the Yangtze river.

Abstract:Based on the EOF analysis of 500hPa height and the mean position of East Asian trough,an East Asian winter monsoon index(H50) is defined. The relationships between H50 and the general circulations, temperature in East Asia are studied,and the variations of H50 from 1951 to 1992 is also analyzed.

Abstract:In the previous paper,the Meiyu front torrential rain process in the Jianghuai Basin on 27,June,1981,has been successfully simulated in terms of MM4.The meso scale structure of the systems associated the two rainbands are diagnosed in this paper by using the high resolution modeling data and the Sawyer Eliassen equation,revealing the special contribution of the jet frontogenesis to the formation and maintenance of the rain belts.Analysis shows that the jet frontogenesis circulation is produced by the coupling of the upper and low level jets and favorable for the formation of the two mesoscale rainbelts.

Abstract:The meteorological causes of the severe flooding of the Changjiang during June-August in 1998 is analyzed by using GMST_BB data.The results show that under the abnormal general circulation caused by ENSO event and the early days heavy snow over the Tibetan Plateau,the floods was caused by the four persistent torrential rainfall processes associated with strong subtropical high lying to west and south of normal position,and weak ITCZ and summer monsoon and frequent interaction between cold air from the mid latitudes and warmer air from the tropics.

Abstract:By using the negative directions algorithm of “recursive resolve”,the content characteristics of dynamical evolution are revealed for inter monthly differences of Equatorial Eastern Pacific monthly mean SST in 1951.1~1997.12,showing the inter decadal variations and abrupt changes of SST.Relations of the content characteristic with ENSO cycles,the total ozone over the both Hemispheres and inter decadal variations of northern Hemisphere tropospheric and stratospheric temperatuers are also discussed.At last,comparison shows that the content of “recursive resolve” is more sensitive to the inter decadal variations of SST in the region than traditional statistical series.

Abstract:This paper applies a non linear stochastic dynamic model with threshold to analyze the rainfall in the Yangtze and Huaihe river basins of east China.The results show that there are obvious differences of the responses of rainfall to external forcing in different threshold regions,indicating some non linear characters.The model can simulate the variations tendency of the rainfall satisfactorily.

Abstract:Three different statistical interpolation schemes respectively based on the principal component regression(PCR) of empirical orthogonal function(EOF),the iteration of EOF(IEOF) and the canonical variable regression(CVR) of principal component are adopted to interpolate the same missing data fields.Contrast experiments show that the interpolation precision of all kinds of schemes is associated with its parameters.If the pencentage of missing data station numbers is less than 60%,no matter what distributions these stations show,all schemes,especially CVR exhibit a satisfactory accuracy,and this character becomes more significant when data missing goes a longer time.

Abstract:In the context of POP technique,analysis is carried out of tropical monthly mean SSTA.Results show that the most important four POPs are closely related to El Nino/La Nina events,indicating that the event has complicated time space structure.Based on POP analysis,a POP neutral prediction scheme is given,which can integrate multiple propagating POPs and make quantitative prediction.The dependent and independent sample hindcast experiments show that the scheme can make forecast four months in advance,and the predictive skill of El Nino/La Nina event stages is higher than that of non event stages.

Abstract:This paper investigates the several verification techniques and their skills cores about probability of precipitation(POP),and presents a new reliability index which will be adapted to Chinese POP operation in accordance with the forecast probability and observed frequencys distribution curve.Verification results show that the POP forecasts in Beijing in 1995 are reliable and skillful for light rain,but lesser reliable for 24-36h forecasts of moderate rain .However,the analysis suggests that the skill scores would be biased in the place wherein the climatic frequency of precipitation is low.

Abstract:By using SVD method,this paper develops a multivariate linear statistical climatic forecast model to perform a short term climatic sea surface temperature(SST) forecast test in several areas of the tropical Pacific.The forecast correlation skills for the different forecast periods are examined by historical independent sample tests.The results indicate that:the SST forecast correlation skills for each season are very different in different sea areas;there is the highest predictability in the west of equatorial Pacific(Nino4 area);and the forecast performance is stable under most conditions in this areas,with an excellent skill for winter SST forecast made at the end of summer.It is demonstrated that better forecast performance would be obtained when SST and SOI are included in predictors than when single SST or SOI is included.Sometimes,the forecast skills are more excellent when the earlier successive two or three seasons SST and SOI are taken as predictors,although,most of forecast skills are higher when one single seasons SST and SOI is taken as predictors.

Abstract:In the context of the data of atmospheric turbulence observed over the Nansha islands sea region,investigation is performed of aerodynamic roughness length(z0) and neutral drag coefficient(C_DN),by use of Brutsaerts hypothesis,the formulas which are used to get bulk exchange coefficients(heat transfer coefficient CHN ,water vapor exchange coefficient C_EN) are derived both over the smooth and rough sea surface.On this basis,the distributions of aerodynamic roughness length,drag coefficients and bulk exchange coefficients with the wind speed(u) at the height of 9.4m are discussed and some interesting results are obtained.

Abstract:Using the 1951-1997 monthly temperature,rainfall and 500hPa height data,the self memory functions β(t) of the regional climate forecast self memory model(SEM) are obtained and their periods are analyzed.1987-1997 flood season(June-August) rainfall and temperature in Jiangsu province are forecasted,and compared with observed rainfall and temperature data.

Abstract:In order to make full use of the accumulative huge climatic data,this paper presents a phase space analogy model of short range climatic forecast with multitime series.By using over 20 time series which are physically related with the climate changes of Yunnan Province,an yearly short range climate forecast model for Yunnan Province is established.The verification of precipitation and temperature forecasts for Yunnan Province shows that the accuracy of anomaly sign of model forecasts of the May precipitation and temperature from 1991-1998,and the June-August and yearly precipitation and temperature from 1990~1997 is 66.3% , 66.6%, and 63.1% ,72.3% ,71.3%,71.1% respectively.

Abstract:Recognition of precipitation echo type is discussed.Based on the characteristics of different precipitation echo types,four indicators such as area size, maximum intensity,intensity gradient,and feature singularity are chosen.Then,a three level judging system is constructed for automatic recognition of three kinds of precipitation types.

Abstract:Doppler radial velocity photograph of mesocyclone is simulated with the Rankine Model and a method to determine mesocyclone center position and radius of maximum wind is proposed.In this method,the product of Doppler radar radial velocity(r) and distance(D) between observed point and radar position is taken as a parameter.It can be proved that the mesocyclone center is the middle point of the line from the maximum to the minimum of the parameter(r·D) and the radius of maximum wind is equal to half the distance between the maximum and the minimum(r·D) according to the geometrical relationship of radial velocity and real air flow.The result from model experiment shows that the method is much better than Wood and Browns(1992) method for estimating typhoon center and radius of maximum wind.

Abstract:This paper presents a new scheme of SNMP_v2 based midlevel manager.It is hoped that the new scheme can remedy the defects of M2M MIB(Management Information Base of SNMP_v2 midlevel manager).Its polling way and alarming mechanism is superior to and its security and interoperability are better than the existing products of the same type.

Abstract:Based on satellite images data,the paper presents a method and its principle for identifying cloud types by using texture.The program design is discussed.The theory and application indicate that different kinds of clouds have different texture features,and texture is the good factor for the classification of clouds.The modularization,visualization and interaction are considered in the program design.

Abstract:It is shown that a family,F,of holomorphic functions in a domain,G,is normal,if each member f∈F.f and its derivtive f′share two distinct finite nonzero complex values IM in G.

Abstract:This paper reports experimental results of electronic spin resonance(ESR) for NINO crystal at T=1.5K and 101GHz.A relationship between spin Hamiltonian parameters D,E,g factor and an orthorhombic symmetry crystalline potential components for a ground state of ions has been established.The spin Hamiltonian parameters D,E and g factor of NINO are calculated.The results agree well with the experimental findings,indicating that relationships suggested are reasonable.

Abstract:A new method is suggested for measuring poloidal magnetic field, a very important plasma parameter,by injecting Lithium beam into the plasma.The physical principle of the method has been analyzed.The experiment has been designed for practice and specifications for experimental instrument are also given.

Abstract:Emperor Kangxi had an original view of wind function.His observation on the difference of wind directions in Shandong and the capital has been erroneously taken as the evidence that he first discovered the wind field discontinuity in the past several decades.On the basis of analyzing the original papers,this paper points out the mistake.By giving two examples of wind's function on the formation of salt and white dragon dunes,it is also demonstrated that Emperoe Kangxi's knowledge of wind was also limited.