Abstract:Based on the Nanjing Institute of Meteorology/Coupled Ocean-Atmosphere Model System(NIM/COAMS),the capability of the model in simulating inter-annual variations is verified in this paper.The 50-year integration shows that the model can simulate the main annual variation of the interface between atmosphere and ocean,and the main character and evolution of the ENSO cycle with a period range of 3-5 years in tropic Pacific.The simulation has demonstrated that the model has the capability for simulating the annual variation and air-sea coupling characteristics.These abilities come from the coupled scheme named flux reanalysis coupling scheme(FRAC) which is able to avoid the influence of climatic mean fields,thus enhancing the simulating ability of the annual variation of the model.

Abstract:By use of single station data in Siberian area and the 1998 GAME/HUBEX IOP data we evaluate a newly modified BATS land surface process model.The results show that the atmospheric forcing of different time intervals gives rise to significant differences in net solar radiation and latent heat in Siberian area.The simulated results for the Huaihe River Basin suggest that the model is able to reasonably simulate the variation trends of land surface characteristic quantities in summer in the semi-humid region of China.Becaue simulated ground temperature and net solar radiation are lower than the observed,simulated sensible heat and latent heat are also lower than the observed.Further study will be carried out to improve the model simulations by choosing adequate soil and vegetation parameters.

Abstract:In this paper a new method of evaluating the efficiency of non-randomized artificial precipitation enhancement-Cluster-Analysis-based Floating Control historical regression Method(CA-FCM) is presented,and compared with the traditional Floating Control historical regression Method(FCM) which does not base on cluster analysis.It is shown from six examples of effect evaluations for cloud seeding operation cases carried out in the central region of Henan Province,that the CA-FCM can more effectively evaluate the efficiency of cloud seeding operations than the FCM,because the CA-FCM adopts cluster analysis which highly improves the correlativity between rainfall distributions in the control area and target area,and chooses the atmospheric precipitable water as a covariant,thus improving the inferential accuracy of natural rainfall in the cloud seeding operation area.

Abstract:Based on the 1950—1998 SST and NCEP/NCAR reanalysis data,the temporal/spatial variations of SSTA in the Western Pacific Warm Pool region have been analyzed in this paper by means of the methods of EOF and composite analysis.Results show that there are two main spatial patterns of the WP SSTA:one is uniform in the whole region,the other is meridionally anti-symmetric.When the spatial pattern of SSTA is uniform in the whole region,in the warm years,an anticyclonic anomaly circulation exists over the warm pool and the westerly/easterly in the subtropical/tropical region are greatly strengthened at 850hPa,while an anticyclonic anomaly circulation over the India region at 200hPa,and the Walker circulation are strengthened,and vice versa.When the spatial pattern is meridionally anti-symmetric,in the north-warm/southcold years,an anticyclonic anomaly circulation exists over the warm pool at 850hPa,the easterly near 15°N and the westerly near the equator are greatly strengthened,while the center of the 200hPa anticyclonic circulation moves to the East Asia,and the Hadley circulation is affected evidently,so the summer rainfall may be above normal in the middle and lower reaches of the Yangtze River,and vice versa.

Abstract:Using the NCEP/NCAR re-analytical dataset and summer precipitation data over North China,we define the Arctic Oscillation index according to the conception of Arctic oscillation proposed by Thompson and Wallace,and study the inter-decadal variation of Arctic oscillations and its relation with the general circulation of the atmosphere and the summer precipitation data over North China.Results show that the Arctic oscillation had obviously inter-decadal variation and an abrupt change in 1969.The inter-decadal variation of Arctic oscillation was in good agreement with the inter-decadal variations of the mid-latitude potential height anomaly field and the 850hPa wind field over Asia.The Arctic oscillation was close related with the frequency of blocking high over the Baikal Lake area and the intensity of East Asian summer monsoon and summer precipitation over North China.

Abstract:On the basis of the sound data obtained from the autumn field experiment in 2002 in Henan country of Qinghai province,and in terms of the 3D cloud-model of CAMS,the paper studies the natural cloud development and simulates the effect of seeding time,seeding position and seeding amount on precipitation enhancement.The study shows that the precipitation in the experiment area is dominated by cold cloud precipitation processes and the ice crystal is the main source of grauple,which is produced by the auto-conversion from ice crystal to grauple and then grows through collecting ice crystals.AgI-seeding should be done before the activation of most ice nuclei start,so as to enhance rainfall through increasing ice crystals content,and deleting super-cooled cloud water.Otherwise,there will be large amount ice crystals grew in natural clouds,artificial nuclei would be useless.

Abstract:The quasi-periodic signals and its interdecadal changes of the monthly rainfall anomaly series are diagnosed over North China by means of singular spectrum analysis(SSA).The results show that the inter-annual oscillations of the rainfall series are strong accounting for about 44.7% of the total variance,and significant oscillation periods are 17 months(quasi-1～2 years),30 months(quasi-2～3 years),60 months(around 5 years) and 11 months(quasi-1 year).The quasi-periodic signals display different features in different sub-division,and their long-term changes are also distinct and different from each other.The singular cross spectrum analysis(SCSA) suggests that there exist evident coupling relations between the inter-annual oscillations of the precipitation series over North China and the quasi-periodic signals of the sea surface temperature(SST) in Nino regions,and the relations vary with time,showing the phased change feature of the coupled oscillatory intensity and the time-varying feature of coupling phase.The dominant couple periodic signals between various sub-divisions rainfall and the SST over different Nino regions,display different features in defferent sub-divisions reflecting the complicacy of responses of the precipitation over North China to the SST anomaly over Nino regions.

Abstract:Correlations between winter/summer temperature in Shanghai and SST in the Pacific areas and their interdecadal variations from 1873 to 2001s have been analyzed in this paper.The results indicate that temperature’s interdecadal variations exhibited obvious change in phase and an overall warming trend,and the correlations between Shanghai’s temperature and SST in the Pacific areas were significantly different on different time scales and in different areas.The correlation differences on different time scales possibly lead to uncertainties and inaccuracy in the statistical forecasting of short-range climate,using the sea surface temperature in the Pacific ocean as a predictor.The uncertainties can be reduced if the correlation differences on different time scales are considered in statistical forecasting.

Abstract:The airborne PMS-detecting data of stratiform clouds in Yan’an in Sep.,2003 are analyzed.It is found that one density distribution function can represent the water drops size distribution in the warm layer of stratiform clouds in Yan’an.The function is used to fit the size distributions of small cloud drops,big cloud drops and raindrops.The fitted spectrum distribution is well matched with the observed one,and the correlation coefficients of their characteristic values are greater than 0.945.The calculated mean diameter,square-root diameter,cubic root diameter and concentration are also close to the observational results and the fitted size distribution is able to reproduce the feature of observed size distribution well.

Abstract:Using the PSU/NCAR MM5,control and dry experiment for the explosive cyclone process of 19th to 21st December in 1981 over the Western Pacific are performed.The results show that the tropopause and isothermal surfaces were raised by latent heat release in the upper level,and the disturbance trough was formed at the upper level:due to the adiabetic cooling of the ascending flow.Its adaption process resulted in the inertial instability in the upper level.Inertial instability always existed in company with the strong inertial stability area,furthermore,the acceleration field caused by these two factors gave rise to air convergence and divergence in the upper level,which made the cyclone strengthened and precipitation enhanced.The reinforced precipitation in turn caused latent heat release enlarged again,leading to inertial instability augmented.The process of positive feedback was favorable for the deepening of the cyclone.

Abstract:All data used are the summer(JJA) temperature of 91 stations in Northeast China from 1955 to 1998.We use the harmonic analysis to separate interannual and interdecadal variations of summer temperature anomaly,further our study on the spatial and temporal characteristics of the two different time scales,and finally apply the REOF method to demarcate the climatic subarea of temperature anomaly,aiming at looking into the abnormal characteristics of different time scales in local regions.The results show that:1)the interdecadal component of variance is obviously larger than the interannual component in the most part of Northeast China;2)the interdecadal variation character of regional temperature anomaly is mainly a linear rising trend,and the large range anomalous high(low)temperature frequently occurs when the interdecadal and interannual anomaly are both positive(negative);3)the temperature anomaly can be divided into four patterns: southern,northern,eastern and western patterns,in which the interdecadal variation of the southern and western patterns is relatively important,while the interannual variation of eastern and northern pattern is relatively important.

Abstract:Distributive characters of water vapor in Western China are analyzed in this paper by using the NCEP monthly mean specific humidity data from 1958 to 1997.Analysis results show that the structure of the vertical distributions of water vapor is very similar,the center of water vapor above the 850hPa level laid over the Qinghai-Xizang Plateau,and the water vapor content mainly concentrated in the lower atmosphere below the 500hPa level in May to October in a year,especially in July moisture was most abundant.The content of water vapor reduced obviously with altitude.It was largest in summer,next in autumn,and smallest in winter.The interdecadal variations of moisture in the recent 40 years show that summer moisture has linearly reduced,especially since the 1990s;while winter specific humidity has linearly increased;and the interdecadal trends of January and July specific humidity were oppsite in phase.

Abstract:The hyperellipsoid equation is used to describe the shape of small particles,and the surface of these particles is drawn and discretized using Matlab.Then the scattering features of some particles are computed by using the T-matrix method and the results are compared with those from other methods.

Abstract:The paper selects the daily real observed data over the area between 30-50°N,and 100-120°E from May to September 1998—2004,separates 0800 and 2000BST streamline fields at 500hPa and 700hPa levels into the smooth and separated streamline fields.The result show that mesoscale systems which are blurred in the original streamline fields are clearly discernible in the separated streamline fields.Then,based on the analyses of the movement,evolution and weather character of those mesoscale systems,this paper summarizes main mesoscale systems producing Datong’s convective strong precipitation and heavy rain,and builds prediction models for convective strong precipitation and heavy rain,thus providing some evidence for Datong’s weather prediction.

Abstract:By using the air temperature data from 1960 to 2004,the seasonal and inter-annual variations of temperature in DaLian are studied in this paper using methods of linear trend estimate,Morlet-wavelet analysis,and temperature trend coefficient analysis etc,with inter-annual and inter-decadal variations of winter temperature being emphatically studied.It is found that the warming trend is obvious in four seasons,and the warming rates in spring and winter are higher than those in other seasons.The winter temperature in DaLian showed a decreasing trend in 1960’s,but it began to rise distinctively in 1970’s,and the warming trend was very obvious in 1990’s.The variations of winter temperature in DaLian were consistent with those in whole China.

Abstract:The 3-D atmospheric wind field in a strong precipitation event on July5,2003 in Anhui Province is retrieved according to the retrieval theory of dual-Doppler radar in the cartesean coordinate system,and results show that the retrieval of dual-Doppler radar is able to detect more detailed structure of 3-D atmospheric wind field.

Abstract:Based on Monthly high temperature data in summer(JJA) from 1961 to 2003 at Nanjing,Hangzhou and Nanchang stations,quite complete time series of severe high temperature are established,and the climatic characteristics and disaster mechanism of high temperature in these areas are analyzed.The observed data in these areas show that oppressive weather lasted for a long time,extreme high temperature was high,daily average wind speed relatively low and daily average humidity higher during the high temperature process.The subtropical high over East Asia is the main climatic system that induced the summer high temperature disaster in these areas.A forecasting model of high temperature days is established using the methods of mean generating function and optimal subset regression.The varification of the 42 years historical records shows that the model can forecast high temperature in these areas successfully.Therefore it can be applied in climate operation.

Abstract:This paper discusses a approach of computing the E_CAP in detail,by adopting theMM5V3.5） output data,introducing an atmospheric thermodynamic variable,density temperature T_ρ,and according to the reversible saturated moist adiabatic process in the environmental atmosphere.Based on this,the energy-helicity parameter I_EH is introduced.Besides,through analyzing the value variations of the E_CAP and I_EH parameters in the "03.7 "Jianghuai Meiyu period severe convective process,it is found that E_CAP and I_EH parameters are usefull in the prediction of the severe storm’s occurrence and development,and worth noting in operational predictions.

Abstract:The diagnostic analysis of 500hPa circulation features of the exceptional high temperature in summer 2003 in Jiangxi Province shows that the exceptionally strong subtropical high was the main cause responsible for the high temperature.After generally investigating the correlation of summer high temperature in Jiangxi with the 500hPa height fields and SST fields from 1959 to 2002,and comparing the composites of 500hPa height and SSTA of high and low summer temperature years,it is found that the positive SSTA in the equatoral central-east Pacific in the previous October and the negative height anomaly around Novaja Zeml’a in January have a close relation to summer high temperature especialy,the SSTA in the previous October has a good relationship with the subtropical high in the subsequent summer.

Abstract:This paper presents a new binary search algorithm which makes use of bit message to delimit the searching scope.The feasibility of the algorithm is proved by experiment and the algorithm can be used in some special cases.