Current Issue

• THE SIMILARITY BETWEEN THE MAPS OF SOIL TEMPERATURE AND PRECIPITATION ANOMALY OF THE SUBSEQUENT SEASON
• Tang Maocang;Elmar R. Reiter
• 1986 Vol. 5 (4): 293-307. 
• Abstract ( ) PDF (939KB) ( )
• Based upon observations in the United States of America it was also found as in China that seasonal mean patterns of soil temperature anomalies at a depth of 40 inch looked similar to the patterns of precipitation anomalies during the subsequent season. The axes of maxima and minima of soil temperature anomalies usually lay close to the axes of precipitation maxima and minima. The mean distance of these two axes were less than 2 Lat. with a percent of 83.7%. Soil can be considered as a filter for the various climate disturbance. The low-frequency disturbance will penetrate the deep soil. The relationship between the frequency and depth is shown as zm=√τ·K _s/π, where τ is the period of disturbance, K, is the heat conductivity of soil, Z _m is called the depth of maxima in formation.

• A CONVECTIVE ADJUSTMENT SCHEME FOR T AND q IN ENTIRE LAYER USED IN THE NUMERICAL MODEL
• Chen Yuejuan
• 1986 Vol. 5 (4): 306-314. 
• Abstract ( ) PDF (440KB) ( )
• A convective adjustment scheme developed for the p-σ combined vertical coordinate five-layer primitive equation model is presented in detail in this paper. Besides the temperature, the humidity field is also adjusted with this scheme. The use of this scheme has made the avoidance of the hydrostatic unstable which occured in the upper layer when the original limited layer dry convective adjustment scheme for T, q and ??? was used, and allowed us to carry the integration of the model over a much longer period. The simulated distributions of the precipitation rate are also improved.

• STOCHASTIC ANALYSIS OF ZERO-DIMENSIONAL CLIMATE MODEL BASED ON FOKKER-PLANCK EQUATION
• Liu Yuhe;Cao Hongxing
• 1986 Vol. 5 (4): 315-324. 
• Abstract ( ) PDF (626KB) ( )
• In this paper the climate system was viewed as the statistical ensemble possessing stochastic perturbation. A Fokker-Planck equation corresponding to the ensemble was derived from zero-dimensional energy balance model and two stable solutions were given. One between the both solutions corresponds to present climate; other, glacial climate. The investigations of sensitivity of climate model show that the results using Fokker-Planck equation is basically close to those of Budyko and Sellers in the response of climate system to the deterministic variation of solar constant. But in the response of climate system to the variation of stochastic variation of solar constant we get new results. Namely the stochastic fluctuation of solar constant will lead up to the decreasing of temperature in the period of both glacial and interglacial and cold climate, when the average of solar radiation keeps unchanged and the fluctuation of solar constant is larger than 31 percent, the present climate state will not occur.

• NUMERICAL EXPERIMENTS OF A TWO-LAYER MODEL WITH INTERNAL BOUNDARY OF TOPOGRAPHY
• Ouyang Shoucheng;Liu Zheng;Meng Guangyi
• 1986 Vol. 5 (4): 325-331. 
• Abstract ( ) PDF (397KB) ( )
• It is intended in the paper the real large scale topography will be treated as internal boundary wall to deal with numerical weather forecast problems with topography. It is quite similar to the treatment of external lateral condition of limited area model.For simplicity, in the paper the terrain of the Tibetan Plateau and Rocky Mountains was firstly taken as a rectangle and possessed E-W(like the Tibetan Plateau) and S-N(like the Rocky Mountains ) orientation, respectively.The experiment without topography shows that the main trough moves eastward and weakens gradually.But incorporation of internal boundary obstacle into two layer model leads to deflecting effects of flows, split of main trough in S-N direction and short wave disturbances in east side of terrain obstacle, especially in S-N terrain orientation (like the Rockies). In the experiment results with and without topography, the weather systems in west side of terrain obstacle are quite stable.It seems that topography only influence the weather in east side of terrain.In the stable experiment, Davies scheme is better than the others to minimise the reflectipn of boundary.

• CHANGES OF AIR TEMPERATURE OF QINGHAI-XIZANG PLATEAU AND ITS NEIGHBOURHOOD IN THE RECENT 30 YEARS
• Li Cunqiang;Tang Maocang
• 1986 Vol. 5 (4): 332-341. 
• Abstract ( ) PDF (613KB) ( )
• In this paper, we have used the recently air temperature data of China more than 30 years and air temperature data of Srinaga and Leh which are both at the west side of the Qinghai-Xizang Plateau. By using the technique of power spectrum and filter, we have analyzed the periodicity and tendency of the changes of annual mean air temperature over and around Qinghai-Xizang Plateau.We have found that there is the most obvious period of 7-10 years over above regions, especialy to the east and north sides of the plateau, the other one is periodic vibrations of a quasi-three years.Both maximum and minimum of air temperature vibration firstly appear in East Plateau. They are also 8-10 years earlier than that in East China. The maximum standard deviation of monthly mean air temperature occurs firstly in the east part of the Plateau as well, then it spreads eastward and northward in leapfrog way and arrives at the north and north-east parts of China in March.

• CORRECTION OF VERTICAL VELOCITY IN PRESSURE LAYERS DIVIDED BY UNEQUAL INTERVALS
• Chen Yuchun;Yan Hong
• 1986 Vol. 5 (4): 342-354. 
• Abstract ( ) PDF (785KB) ( )
• So far, we all use the O'Brien's formula to correct the vertical velocity ^[1], which was derived in vertical pressure layers divided by equal intervals, not by unequal intervals. In this paper the revised correction formula of vertical velocity in pressure layers divided by unequal intervals was given. We calculated the vertical velocity with the same set of data in terms of the abovementioned both formulas. The intercomparisons of both results reveal that: 1. No matter which integrating scheme(upward or downward) we use, there are the difference between the both results, especially over the Plateau area. 2. The more the vertical pressure intervals AP is, the large the difference between both results is, except when integrated from down to up under setting P _T=0. 3. Compared with the results in pressure layers divided by equal intervals, when integrated from down to up using correction formula of unequal pressure intervals, the computed vertical velocity at lower layers increase sharply, but those at upper layers decrease obviously. 4. When integrated from up to down, both correction results at some layers and grid points have opposite signs. 5. The difference between both correction results when integrated from up to down is far larger than when integrated from down to up. The maximum value of the difference is the order of ±21.0×10 ^-4hPa·s ^-1. Therefore, when computed the vertical velocity in pressure layers divided by unequal intervals we should make use of the revised formula.

• NONLINEAR BAROTROPIC ROSSBY WAVE AND ITS STABILITY
• Huang Jianping
• 1986 Vol. 5 (4): 355-363. 
• Abstract ( ) PDF (481KB) ( )
• In this paper, beginning with the nonlinear barotropic vorticity equation describing Rossby wave and using the geometric theory and the stability theory of the ordinary differential equations, the existence and stability of Rossby wave are discussed. It is shown that the existence and stability of Rossby wave demand(β-d ²u/dy ²)/(k ²+l ²)(c-u)<0, and the nonlinear barotropic when the V is zero, the initial vorticity is not zero. Furthermore, we obtain two analytic solutions for the Rossby wave.