Vol.3, NO.1, 1988

Display Method:
The Climate Oscillations of West Pacific Subtropical High
1988, 3(1): 1-9.
Based on the data of the west Pacific subtropical high area index and equatorial eastern Pacific SST during 1951—1984, the long-term evolutive characteristics of the subtropical high and their relations with the SST and solar activity have been investigated. It is found that the intensity of the subtropical high has the obvious staginess and periodicities with 3. 2, 3. 3, 11. 3 and 22.5 years. There are different period lengths during different stages. The 3—4 year oscillation of the subtropical high is controlled by SST. When the intensity of the subtropical high evolutes from weak to strong, the change of the SST will be ahead of the former one, and vice versa. The periods of 11.3 and 22.5 years would be influenced by solar activity. All of the turning years of the subtropical high’s stage are almost around sunspot maxima and minima with 11 year period. The subtropical high would be strong in odd cycle of solar activity and weak in even cycle of solar activity. These results would be useful for the long range forecasting of the subtropical high.
The Coupling Oscillation Between the Southern Oscillation and the Sea Surface Temperature and Trade Wind
1988, 3(1): 10-16.
In this paper, by using multi–spectral analysis, some factors such as the southern oscillation index, sea surface temperature and trade wind index have been calculated, and the coupling oscillation between the southern oscillation and the sea surface temperature over the equatorial Pacific is revealed. It is found that their variations are seemed to be out of phase, and there is a few months phase difference between the sea surface temperature and the southern oscillation. In addition, the correlation between southern oscillation and the trade wind over the Pacific is analysed.
The Application of Seven-level Primitive Equation Spectral Model to Numerical Forecasts for a Limited Area
1988, 3(1): 17-24.
In this paper, a higher resolution model for a limited area based on the Northern Hemisphere spectral model is presented. By applying the characteristics of the spectral model, some new treatments have been added on it for the expansion of initial meteorological field and for the calculation of nonlinear terms in the time integration in this model so that the initial meteorological field and the results of integration can be more accurate in a limited area (50o—140oE, 20—60oN). This model may be used to prepare for both the forecast with lower resolution (5o×5o) in the Northern Hemisphere and the forecast for a limited area with higher resolution (2.5o×2.5o) in the same time. The control experiments for 24 and 48 hours forecasts have been made by using data analysed by ECMWF and the better results have been obtained
A Finite-difference Scheme for the Two-way Nested Mesh Model
1988, 3(1): 25-35.
A finite-difference scheme with variable mesh scale for the two-way nested mesh model is designed, to which the finite difference formulas with different order of accuracy in coarse and fine meshes are applied. The calculation repeated at the grids of the coarse and fine overlapping meshes is avoided. The analytic solutions and the results of the numerical experiments show that as compared with other difference schemes with non-uniform gird, the scheme would produce small false reflectivity for the shortwave. A nested mesh model of barotropic primitive equation is constructed by means of the scheme. A time-spliting and spatial-spliting method is used in the model, in which the two-dimensional equation is transformed into two sets of one–dimensional equation so that the numerical calculating and computer programming are simplified. A series of the results of numerical experiments using ideal fields as initial data show that the model is computational stability. Finally, by the use of the model, some results for forecasting typhoon track are given
Measurements and Analyses of Atmospheric Optical Properties over Tibetan Plateau
1988, 3(1): 46-55.
The data getting from a 10–channel solar photometer in Lhasa in June 1986 (during TIPEMX–1986) have been used to analyse the atmospheric optical properties over Tibetan Plateau. The results presented in this paper are as follows: The values of the total optical depth in Lhasa are only about half of those in Beijing, which indicates that atmospheric transparency over Plateau is good. The Chappuis bands of ozone can be used to retrieve the total ozone content of atmosphere in Plateau areas. The majority of aerosol size distributions over Lhasa can be best represented by the Junge distribution. The total moisture content of atmosphere not only relates to the circulation situation but depends on the moisture transportation.
Dynamic Processes of the Moving and Developing Lows on the Qinghai–Xizang Plateau During the Early Summer
1988, 3(1): 56-63.
Through analysis of the processes of the developing and disappearing lows on the Qinghai –Xizang Plateau in June 1980—1983, the relationships between 300 hPa southwest jet and the moving and developing lows on Qinghai–Xizang Plateau have been obtained, and the action of A (advection) and fξ’ (nongeostrophic) terms in divergence equation have been discussed. The existence of jet determines directly an increase in A and fξ’ terms. It is an important dynamic cause for the lows eastward moving and developing. Finally, the dynamic processes of the lows developing and moving along the northern side of jet’s axis have been detailed by advection equation and adjustment equation
The Effect of Cloud on the Radiational Oscillations over Qinghai-Xizang Plateau in Summer 1979
1988, 3(1): 64-69.
The power spectrum analyses of atmospheric heating components in Lhasa and nineteen stations over the Qinghai-Xizang Plateau in Summer 1979 have been calculated. It is found that there is a 8—12 days quasi-periodic oscillation for the radiation, latent and sensible heat. Furthermore, we focus our discussion on the effect of clouds on quasi-periodic oscillation of the radiation heat
The Processes of Mesoscale Systems of Hail Storm over the Northeastern Tibetan Plateau
1988, 3(1): 70-77.
In this paper, we used the hail storm field experimental data in Gausu Province in 1979—1980 to choose several typical cases based on the different synoptic patterns and to divide into two types. Then the composite diagnostic analysis has been done by the averaged hourly surface mesoscale meteorological fields and the probability of radar echo, shower and hailfall. Two kinds of the processes of different mesoscale systems have been obtained. The diagnostic analysis of the meteorological elements indicated that the divergence, moist static temperature analysis of the meteorological elements indicated that the divergence, moist static temperature advection, and vertical velocity are closely related to the mesoscale systems of hail storm over the northeastern Tibetan Plateau. The areal convergence of hail storm which has a certain prior indication can be used for nowcasting the convective weather
Influence of Cold Advection in Mid–and–upper Troposphere on Squall Line Occurrence
1988, 3(1): 78-85.
The occurrence of squall lines is frequently associated with instability energy and vertical wind shear. In this paper, a method for diagnosing temperature advection in mid-and-upper troposphere is proposed, with which the advection magnitudes between 700 and 300 hPa in several cases are analysed. Results show that the cold advection would cause an increase in the instability energy E between 700 hPa and 300 hPa and the magnitudes of E and could present a certain indication for the formation of strong squall lines. It is pointed out that vertical wind shear and its change are closely correlated with the temperature advection. It is also emphasized that analysis of horizontal distribution of instability energy and cold advection is useful for forecasting the area in which squall lines occur.
Climatic Characteristics of the Strong Heavy Rain in the Northern China
1988, 3(1): 86-92.
In this paper, by using the rainfall data during the last 30—40 years, we analysed the climatic characteristics of the very heavy rain in the northern China. It is shown that the heavy rain days in the northern China are less than that in the southern China, but the rain intensity is stronger. The maximum rain of various rain periods exists always in the northern China, most rain days are in midsummer. The maximum of the daily rainfall contributes significantly to the total rainfall of the year, and its annual variation is obvious. Furthermore heavy thunderstorm is often associated with heavy rainfall in the northern China, duration of rain is short and rainfall coverage is small
The Outgoing Longwave Radiation (OLR) Climatological Mean Charts and Its Analyses
1988, 3(1): 93-99.
The OLR climatology mean charts are presented using the OLR data (1974.6—1984.5) gained from NOAA series satellites. The dealed procedures of OLR data, the analyses and applications of these climatology mean charts are also discussed in this paper