Abstract:Symmetric instability is analytically investigated of the right side of upper air jet entrence region and the left side of lower level jet entrance region with non-thermal wind gradients available in the context of a ƒ-plane, non-hydrostatic equilibrium and acoustic wave filtering model for meso-scale research purposes, arriving at an analytic expression of perturbation streamfunction, whereby qualitative analysis is done of the existence of non-thermal gradients, meso perturbation wave structure and spatial distrbution features of wave amplitude. And obtained analytically are the disturbance half wave-length L_c and criterion for symmetric instability with non thermal gradients available. Results presented can account for causes of vigorous rainstorm genesis at jet entrance regions one atop the other at high-and lower levels.

Abstract:This paper concerns the persistent anomaly of North Pacific atmospheric circulations, indicating that the genesis, development and decay of positive anomaly is in pattern closely similar to the negative, both originating from the variation in the departure situation over east Asia and the western Pacific, with regularly ranging anomaly sectors in the North Pacific and east Asia, accompanied by corresponding change in atmospheric circulations over east Asia and the whole northern hemisphere; persistent anomaly of Northern Pacific circulations has major effect on weather over China. Diagnosis and numerical studies show a very close relation between persistent summer anomaly in the North Pacific circulation and SSTA of mid and lower latitudes.

Abstract:Study is undertaken of South-China Sea (SCS) monsoon onset and Asian monsoon establishment features alongside possible mechanisms in the context of 1980～1986 ECMWF gridded data and 1980～1992 Japanese GMS derived TBB data. Results show that the precursors of Asian summer monsoon establishment appear first in the Indo China peninsula to the SCS, followed by west and east spreading; the Indo China is the division between east Asian and Indian monsoon, with the establishment and genesis mechanisms quite different on both sides of the peninsula; Asian monsoon establishment from east to west is closely related to the turning of meridional temperature gradients, their maxima travelling westward and the west spreading of positive temperature difference from the Indo China when winter goes to summer.

Abstract:The conception of wavelet energy spectrum (WES) is posed by comparing the conservation of total energy in harmonic analysis,power spectrum analysis and wavelet transform. The calculations of a compound test series show that the WES has a fine performance in audiovisually revealing the time changes of strength of fluctuations in both time and frequency domains,especially for time changes of cos ω2t×cos ω1t type. The WES analysis of SSTA series in the tropical Pacific suggests that its interannual variability is primarily composed of biennial,quadrennial and annual oscillations,and these components simultaneously strengthen or weaken in a time interval about 10 years.

Abstract:A 3D fog model was applied to investigate the genesis and development of Chongqing fog. The results are roughly coincident with the reality. A set of sensitivity experiments help us gain further information on the contributing factors of the study fog.

Abstract:In the context of August,1982-July,1983 radiation balance data of the Qinghai-Xizang Plateau, study is made of the relation between the active surface temperature and surface temperature, proposing two parameterization schemes on Surface Long Wave Radiation (SLWR) of the form:U=kδσ(T₀+273)⁴andU=δσ[(T₀+273)+ΔT]⁴,, where k and ΔT are indicated by parameterized equations, separately, others being in conventional notation. Retrieved verification shows two formulas to be of the same fitting accuracy with the mean relative error of 3.6 % ec. and suitable for calculating instantaneous and mean flux density, alongside analysed daily and annual variations of k/ Δ T . In the end, SLWR in the target area is investigated and climatic characteristics discussed.

Abstract:Following radiation theory,the relation is derived of GMS measurements to ground global radiation(GGR),whereupon are built 7 models for the satellite data estimation of GGR,of which optimal is sorted out for our purpose. Evidence suggests that the method is suitable for such areas like the Qinghai-xizang plateau where stations are far between.

Abstract:This paper concerns a scheme for a radar rainguage system in measuring rainfall treated by variational calibration. The optimal Z-I relation is established with real time data and the multigrid method is used in solving the Euler equation. These considerations can improve data accuracy in a target region and save time as well.

Abstract:Using 1951～1991 500 hPa height and SST, and 1980～1991 T_BB data, study is undertaken of the features of east Asian monsoon seasonal transition in dry and wet years by means of composite analysis, indicating that different SST patterns and difference in the related air-sea interaction are responsible for slow northerly march of western Pacific subtropical highs on a seasonal basis, with the stronger ridge steadily located around 25°N, causing the summer monsoon rainband persisting in the Jiang Huai drainages for flood. Further, addressed are the effects of the Indo China convection and the change in a equatorial high pressure band as forerunners upon the Jiang-Huai flood/drought.

Abstract:With 1983～1988/1989 seasonally-averaged global heating data, the latitudinal and longitudinal uneven distribution characteristics of the heating anomaly with respect to 6 year mean in these years are analyzed. Based on the heating anomaly is alternate positive and negative anomaly meridionally and there are some main heating anomaly zonally. Numerical simulation is carried out of influence on circulation of latitudinal/longitudinal uneven anomalous heating in terms of a 3D steady primitive equation spectral model. Evidence suggests that the latitudinal uneven anomalous heating enhances obviously the meridianal circulation anomaly which is different from the linear superposition of circulation anomaly caused by those single anomalous heatings while the linear superposition effects of longitudinal uneven anomalous heating is relatively clear.

Abstract:This article is concerned with the problem of significance test of meteorological elements and their fields and introduces a Monte Carlo simulation experiment scheme with the results of usefulness in practice.

Abstract:For calculating invariant quantities a concept is established on mimimum linear correlation group (MLCG) of n-dimensional real vectors, followed by using the Gaussian elimination technique to find a computational scheme for the MLCG, alongside the application to the problem of invariant quantities.

Abstract:In solving the regression equations, collinearity in the design matrix can result in inaccurate parameter estimates. The use of orthogonal matrix transformations such as the singular-value decomposition (SVD) can reduce the effect of collinearity. Also, estimates of the regression coefficients can sometimes be improved through iterative refinement. The application of iterative refinement to the SVD solution of the regression equations is described. Results show that iterative refinement using the SVD can improve regression coefficient estimates in the cases where the design matrix is highly collinear.

Abstract:The paper is devoted to application of the wavelet network technique to nonlinear models for timeseries analysis and the nonlinear approximation by the method is able to construct a nonlinear function that is used to process temperature data, resulting in good fitting accuracy.

Abstract:Introduced are the basic concept and performance of genetic algorithm and documented are the feasibility and limitation of artificial neural network used as a timeseries prediction model, whereupon is proposed a scheme of both techniques in combination for predictive purpose, along with the calculations and discussion of the model and results.

Abstract:The paper is devoted to the comparison of cloud motion wind generated by a CWIS (cloud motion wind inferring system) to that by JMSC (Japan Meteorological Satellite Center) and radiosoundings.

Abstract:Climate variation results in the change of agriculturally climatic resources and their variation affects the change in the crop growth period (CGP). This paper investigates the variation in accumulated temperature for main crop growth from 1980 in this province, discovering differences of the thermal variation during a range of CGP on a geographical basis. It is found that the decreasing (increasing) thermal resources will cause prolonged (reduced) CGP in mountains (plains).

Abstract:In terms of 1954～1989 summer (June～July) rainfall over South China and monthly mean global SST, study is undertaken of the relationship between the South China summer rainfall (SRSC) and SST. It turns out that SRSC is negatively correlated to the previous January SST over the western North Pacific at a significant level, suggesting that anomaly increase (decrease) of the SST aforementioned is beneficial to summer flood/drought over South China. Results further indicate that noticeable negative correlation between SCSR and SST is maintained over the Philippines and its surroundings, mid latitude North Atlantic during the previous spring and summer with its great significance to predicting summer flood/drought in South China.

Abstract:Based on case diagnosis we investigated the symmetric instability of a rainstorm over the loess plateau, along with the distribution of the criterion of the event. Results show that symmetrically unstable stratification is of importance to such a weather process and that the criterion is <0 in magnitude over the rainfall area.

Abstract:The 1D model for unsteady boundary layer is used to simulate nocturnal temperature distribution features with vegetation available in comparison to those with no vegetation existent, and investigate the impact of vegetation on the temperature in vertical.

Abstract:The stochastic dynamic model describing the air-sea interaction is transformed into a Fokker-Planck equation that is then solved by the matrix continuous fraction method. As an example of the solution, the warming by CO₂ increase is calculated and its increment is 1.2℃ while CO₂ concentration in the atmosphere increases from 330 to 660 ppm. In the model the dominant period is 3～4 years and it is revealed that the periods tend to get longer when CO₂ doubling occurs.