Abstract:When the momentum,energy and circulation of a fluid in a quasi-geostrophic baroclinic two-layer model are specified,the minimum enstrophy solution of the baroclinic fluid is first obtained by the variation method,and is none other than an exact one of nearly steady baroclinic finite-amplitude problems.If the ratio of length to breadth of the channel,the average depth of fluid and the energy are greater than their critical values respectively, and the circulation is of no vertical shear,the exact solution is the finite amplitide baroclinic Rossby waves;otherwise it is the zonal flows.″principle of no-coexistence″is first proposed meaning that all wavenumbers between the barotropic and the baroclinic components of nearly steady finite amplitude Rossby wave in the baroclinic atmosphere are not the same,This indicates that two kinds of nearly steady waves have quite different horizontal and vertical structures,results that agree with observational facts and outcome of numerical experiments.

Abstract:This paper is devoted to a dynamic model for observational study,which does not depend on statistical concept nor on any a priori theoretical model of the object.Consequently,it pocesses great generality.Recursive similarity is the central concept of the research,resulting from which are neighborhood function,jumping,evolution similarity and calculable index,responsible for describing the evolution properties of the observational sequence.As a target,the reconstruction of a dynamic system based onan observational(vectorial or functional)series and the article is only part of the research towards the goal.

Abstract:Using 1980～1983 ECMWF objective analyses investigation is made of the energy conversion between synoptic eddies and time mean flow for any month of a selected year,and a particular month of a normal and an EI Nino year. Evidence suggests that in the track region the synoptic eddy kinetic energy and effective potential energy are maximal so that energy conversion between such eddies and time mean flow are strongest;in the entrance and exit sectors of the track the conversion is reversed in direction such that the storm track is maintained in a more steady area.

Abstract:The purpose of the paper is to reconstruct the refractive index profile of layered medium from the electromagnet ic reflecte signals. Nonliner renormalization is performed of Riccati equation,which is made intergratable and with which the relation between the refractive index and the reflection signals in time domain is derived.Medels of different forms and scales are used to check the procedure.Numerical results show that this nonlinear renormalization technique is a stable and simple procedure of high accuracy.

Abstract:A quasi-geostrophic barotropical model is employed for performing five experiments with the integration in excess of 120 hours to investigate the interplay between a typhoon circulation and a smaller-scale vortex,Results suggest that the interaction can result in obvious change in the asymmetric structure of the typhoon,thereby causing the deviation of the latter′strack from the expected one.

Abstract:By investigating the SST departure pattern features over the North Pacific(60°N～20°S),the North Pacific oceanic current segment is found to be the strongest SST anomaly sector in the midlatitude Pacific,together with the discussion of the interrelation between the SST area and at mospheric ci rculations. By comparing the in teraction between the equatorial central/eastern Pacific SST anomaly and atmospheric circulations,a remarkable PNA pattern is found to be in the atmospheric circulation. Besides,the atmospheric circulation serves as the initiator for the interplay between midlatitude North Pacific SST anomaly and Northern atmospheric circulations.

Abstract:Using a primitive equation model with a spheric band domain,a numerical study is carried out of the effect on rainfall of 1991 Pacific SST anomaly in the leading region with the affecting mechanisms investigated.Evidence suggests that the SST abnormality has its impact confined largely to tropical and subtropical latitudes,and its direct influence is to mtxlify the sea-air exchange of sensible heat and water vapor,causing the variation in the temperature and flow fields and condensation feedback that will modulate precipitation pattern.

Abstract:Based on measurements from an experimental area and considering the characteristic shape of and the propagation properties of solar radiatio11 amongst the canopy of paulownia,a model is constructed for solar radiation distribution inside a patch with crop-paulownia intercropping at a range of densities under such skies as clear,cloudy and overcast.Compared to other analogs,the present model can better imitate the solar radiation pattern daily course in such fields,with the factors affecting the distribution investigated,thereby providing a basis for preparing an effective intercropping model.

Abstract:Observation was made with the ground raindrop size meter synchronously with a hygroscopic paper for the spots to investigate the reliability of the meter measurements.Results show that 1)both types of data yield the significance level of 0.005 for the characteristic quantity linear correlation except the mean diameter,mean square rcot diameter similarity and 2)double-factor variance analysi indicates that no significant difference exists in the characteristic quantities but mean diameter and mean square rcot diameter of the size distribution and rainfall intensity.

Abstract:This paper presents a scheme for analyzing the spectral structure of spherical functions of squared norm of anomaly field set using the coefficients of the function expansion,wherewith analysis is implemented of northern 500 hPa height for January and July in 1951～1986,separately. Results show that the spectral structure of the anomaly sets is characterized by low-dimension and low-order,and the salient features of the anomaly circulations and their seasonal/interannual variations can be accurately described in virtue of less than 50 components of the functions.

Abstract:By using the precipitation data from May to August(1951～1987)at 34 stations in the upper and middle reaches of the Changjiang River and maximum entropy spectrum method of the moving sample series,an objective and detailed study is performed on the periodic oscillationfeatures of the wet season precipitation in the reaches,Results show that there is an obvious quasi-biennial oscillation in the data.In addition’we study the distribution of the oscillations.The other periedic oscillations are not so obvious and stable.

Abstract:Some conclusions have drawn from the diagnosis,comparative analysis and numerical study of typhoons with varied precipitation intensities. It is found that the typhoon rainstorm is associated with the presence of a frontal zone,high- and low-level jet;an intense frontal zone is responsible for the enhancement of 200 hPa southwesterly jet and ageostrophic divergence on the rear right,whose effect will excite gravity-inertia waves;the adjustment(spanning 3～6h)is none other than the abrupt intensification of the rainstorm,giving rise to the strengthening of low level jet that carries abundant water and momentum into the rainfall area for still heavier rain;after the ending of the adjustment,precipitation is kept steady.

Abstract:The present paper is devoted to the causes of local severe rainstorm produced by Typhoon No.8807.They are 1)abundant water carried by the storm;2)highly unstable energy for and triggering to the rainfall offered by the low-level meso frontal zone in relation to the spiral-form cloud/rainfall sector of the typhoon and inhomogeneous solar radiation;3)local topography and frictional factors responsible for the fact that Yichang is a preferred seat for convective cloud development;4)upper-level meso pressure fall system and vorticity factor enhancing the growth of the cloud.

Abstract:A five-level primitive equation operational model developed by the US NMC is used in control experimenting with several types of lateral boundary conditions commonly used in terms of the one-way automatic nesting method.Results show that the intensive grid scheme can improve the accuracy and,of the boundary-handling schemes,Davies technique is optimal that causes no disturbance in the vicinity of the boundary and produces smooth isolines and high stability without the help of other treatment.The scheme is useful in making operational prediction more accurate.

Abstract:Based on ERBE and ISCCP data,a study is performed of the effects of the factors like total cloudiness upon the earth-atmosphere net radiation (EANR),and also of its relation to other components and the surface net radiation,Results show that the maximum effects on the earth-atmosphere net radiation are exerted by the planetary albedo and earth-atmosphere absorbed shortwave radiation,with the impact of cloud cover and latitude shown mainly through the variation of values of the two factors above;OLR plays a relatively feeble role;the correlation is obvious between EANR and ground net radiation. Further,an analysis is conducted of the EANR distribution over the country with the result that the annual curve is marked by summer(winter) high(low) value for all parts of the nation,with the influence of cloudiness and latitude chiefly responsible for the maximum having a temporal shift.

Abstract:A multigrid Method (MGM) is employed to calculate five fixed solutions to the first boundary-value problems of Helmholtz’s Euler equation,which are compared to the super relaxation iteration with variable coefficients,Evidence suggests that the required time of the MGM is less than that of the iteration for the same accuracy with the time/efficiency ratio greatly enhanced with increased grid number,thereby exhibiting advantages in finding numerical solutions of a large-scale difference equation.

Abstract:Based on agrometeorological and plant physiological principles and in terms of the data of potted rice growing in a climatic box,a model was constructed to simulate the net photosynthetic rate of the study crop with the parameters determined and the relationship between the rate and meteorological elements(e.g.,insolation and temperature)investigated.The achieved results provide a theoretical basis for study of dry matter accumulation,distribution and yield formation of the stands.

Abstract:Regression coefficients between Eurasian snow cover sequence and northern mid-upper troposphere geopotential height are used to disassociate the response of anomaly circulations to the snow cover,Evidence suggests that the regressiori response field can display the relation between the snow and circulations hut the amplitude of the correlation center as well,which is bigger in the mid troposphere with a strong equivalent barotropic structure in the mid-upper troposphere.The winter to summer circulations exhibit marked stationary planetary-scale wavetrains as(shown in the response field) NEUP and NPNA in winter,LEU and EANA in summer and differing slightly in spring.These wavetrains display branching with energy transmission as wave front and intercepted subtropically.

Abstract:This paper investigates the relationship between climatic signals and noises,and the problem of upper limit of accuracy of long-term forecasting monthly mean temperature,and concerns the evaluation by three methods of the variance of climatic signals and noises from the daily temperature series of 25 stations in the study area.Results show that,with the absolut eerror smaller by a factor of 0.68 than mean square deviation as the criterion of correct prediction,the upper limit would be within 66%～72%,with little difference between the winter and summer prediction.

Abstract:This article investigates the correlation of Pacific SST with temperatur/rainfall of the study area,deriving some useful findings,which are employed in constructing a system for predicting monthly mean temperature and precipitation and has achieved good results in the context of economic benefits.

Abstract:The 1989～1991 autographic records of wind from 32 weather stations in Shandong Peninsula are used to invedtigate the features of sea-land breeze circulation,including the frequency and vigor of the winds,transition intervals of both,horizontal/vertical scales.Evidence shows that with the sea breeze prevailing,a convergent zone occurs in the central Peninsula,often accompanied by showers and thunderstorms that are sometimes responsible for intensely convective weather.

Abstract:Following the concept of climate jump based on the principal teleconnection pattern and EOF analysis,salient temporal and spatial features are revealed of the wet-season rainfall and summer temperature on a large scale over China in relation to SST in the 1960s,Results show that the jump is somewhat different in time and strength from region to region and from element to element;jump of SST preceded that of air temperature and rainfall;the summer temperatureand rainy-period precipitation bore a close positive correlation to January SST on a twoyear-lag basis.

Abstract:In terms of both long-and short- range annual and decade rainfall data from the east part of the Dabie Mountains,the theoretical probability distribution of precipitation in several segments are calculated.Results show that the theoretical pattern based on 2-3 year dataset and the indirect model coincides quite well with that from long-term data and thus has considerable usefulness.As such,this model for estimating the mountain rainfall with a certain part guaranteed annually is of great value,In the end,the utilization of the rainfall resources is addressed.