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1991 Vol. 8, No. 2

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Nonlinear Stability of Plane Rotating Shear Flow under Three-Dimensional Nondivergence Disturbances
Ren Shuzhan
1991, 8(2): 129-136. doi: 10.1007/BF02658089
Nonlinear stability criterion for plane rotating shear flow under three-dimensional nondivergence disturbances was obtained by using both variational principle and convexity estimate introduced by Arnold (1965) and Holm et al. (1985). The results obtained in this paper show that the effect of Coriolis force plays an important role in the nonlinear stability criterion, and the nonlinear stability property of the basic flow depends on both the distribution of basic states and the way the external disturbance acts on the states. The upper bound of the gradient of the mass density displacement from the equilibrium k2 = is determined by the basic states and one example was given to show the exact upper value of k. The remarks on Blumen's paper were also given at Section 4 of this paper.
Relationships between the Global General Circulation and the Indian Summer Monsoon
M. Sankar-Rao, V. N. Lykossov, E. M. Volodin, A. E. Nikitin, A. I. Degtiarev, Kusuma G. Rao
1991, 8(2): 137-148. doi: 10.1007/BF02658090
The relationships between the global general circulation and the Indian monsoon during active and break phases are investigated with the help of FGGE IIIb data.It was found that the ultralong wave component positive and negative height anomalies over Tibet are associated with active and break monsoon phases respectively. This ultralong wave component has significant effect even upto 22oN over the Indian region which is the monsoon trough region. During a monsoon break, the general circulation was found to be more turbulent in the sense that more waves become energised.It was observed that during a break, blocking prevails over the Siberian region and cold air advection takes place toward Indian region from Siberian region depressing the temperatures over the Indian region by about 1oC. During the break, the Indian region gets connected with higher latitudes by the south winds blowing from polar Soviet re-gions to the Indian region. From active to break phase the zonal component weakens by about 25% from Indian ocean area right upto Alaskan region, along the east coast of Asia.
The Stability of Large-Scale Horizontal Air Motion in the Non-linear Basic Zephyr Flow under the Effect of Rossby Parameter
Yang Fanglin
1991, 8(2): 149-164. doi: 10.1007/BF02658091
The stability of large-scale horizontal motion in the atmosphere is discussed in this paper by using qualitative analysis theory of non-linear ordinary differential equations. Both the non-linear distribution of basic Zephyr flow and the variation of geostrophic vorticity along the latitude (f=f0 + βδy ) are all included in this paper's mathematical model so as to analogue the background field of large-scale horizontal air motion more really in the rotating reference frame of the earth. Some significant results are drawn out from this paper and the conclusions of Li(1986)'s and Wan et al.(1990)'s are extended widely.
A-B Hybrid Equation Method of Nonlinear Bifurcation in Wave-Flow Interaction
Gao Shouting
1991, 8(2): 165-174. doi: 10.1007/BF02658092
In this paper, A-B hybrid equation method is given. This method is different not only from high truncated spec-tral method, but also from amplitude evolution method. Dynamic problem in the baroclinic atmosphere may be transferred into complex Lorenz system by means of the method. Therefore, this method is an effective tool for stud-ying nonlinear bifurcation in wave-flow interaction. Meanwhile, it is of advantage to use this method, because it can overcome a lot of difficulties existing in high truncated spectral method and amplitude evolution method.
Numerical Simulation of the Scavenging Rates of Ice Crystals of Various Microphysical Characteristics
Richard L. Pitter, Renyi Zhang
1991, 8(2): 175-200. doi: 10.1007/BF02658093
Numerical models of trajectories of small aerosol spheres relative to oblate spheroids were used to determine ice crystal scavenging efficiencies. The models included the effects of aerodynamic flow about the ice particle, gravity, aerosol particle inertia and drag and electrostatic effects. Two electric configurations of the ice particle were investi-gated in detail. The first applied a net charge to the ice particle, of magnitude equal to the mean thunderstorm charge distribution, while the second applied a charge distribution, with no net charge, to the ice particle to model the electric multipole charge distribution. The results show that growing ice crystals with electric multipoles are better scavengers than single ice crystals with net thunderstorm charges, especially in the Greenfield gap (0.1 to 1.0 μm), and that larger single crystals are better scavengers than smaller single crystals. The results also show that the low density ice crystals are more effective scavengers with net charges than they are with charge distribution.
Influence of Advection on Marine PBL Development
Ye Weizuo
1991, 8(2): 201-210. doi: 10.1007/BF02658094
Based on the DRS model (one coupled dynamical-radiational model of stratocumulus), though extended to take advection into account, several calculations have been made to estimate its contributions to the thermodynamical structure of the PBL (planetary boundary layer). Advection various calvulations show does affect the development of the PBL, Particularly in cloud forming and evolving. One of the intriguing findings which accords well with observations demonstrates that cold currents create strong convective weather, while warm currents bring about stable weather: produce prolonged low clouds or fogs.
Planetary Stationary Waves in the Atmosphere Part I: Orographic Stationary Waves
Yong. L. McHall
1991, 8(2): 211-224. doi: 10.1007/BF02658095
It is proposed that the orographic stationary waves are required by long-term balance of momentum in the at-mosphere with zonally asymmetric orographic forcing, This hypothesis may be confirmed successfully with the theo-retical model of geostrophic waves. In the Part I, we will explain the observed phase distributions of orographic sta-tionary waves at middle and high latitudes of the Northern Hemisphere, according to the long-term balance of zonal momentum over the stationary orographic forcing. It is revealed that the geographic distribution of stationary waves depends not only on local topgraphy but also on mean circulation fields and angular momentum flux in the atmos-phere. So these waves cannot be simulated by the models in a restricted area.
Planetary Stationary Waves in the Atmosphere Part II: Thermal Stationary Waves
Yong. L. McHall
1991, 8(2): 225-236. doi: 10.1007/BF02658096
The contribution of thermal forcing to the planetary stationary waves will be studied also by assuming that heat balance in stationary waves over zonally asymmetric thermal forcing must be maintained over a long time period. Us-ing the same model of geostrophic waves introduced in Part I, we may explain successfully the observed and simulated responses to the thermal forcing in the atmosphere, such as the wave 1 structure at high levels of middle latitudes, the seasonal changes of the stationary waves in the Northern Hemisphere, the opposite phase distributions of stationary waves at high and low levels of the subtropical regions in both hemispheres and so on.
Satellite Data Reduction Using Entropy-preserved Image Compression Technique
Li Jun, Zhou Fengxian, Gao Qinghuai
1991, 8(2): 237-242. doi: 10.1007/BF02658097
In this paper, three techniques, line run coding, quadtree DF (Depth-First) representation and H coding for compressing classified satellite cloud images with no distortion are presented. In these three codings, the first two were invented by other persons and the third one, by ourselves. As a result, the comparison among their compression rates is given at the end of this paper. Further application of these image compression technique to satellite data and other meteorological data looks promising.
Determination of Kolmogorov Entropy of Chaotic Attractor Included in One-Dimensional Time Series of Meteorological Data
Yan Shaojin, Peng Yongqing, Wang Jianzhong
1991, 8(2): 243-250. doi: 10.1007/BF02658098
The 1970-1985 day to day averaged pressure dataset of Shanghai and the extension method in phase space are used to calculate the correlation dimension D and the second-order Renyi entropy K2 of the approximation of Kolmogorov’s entropy, the fractional dimension D = 7.7~7.9 and the positive value K2 ≈ 0.1 are obtained. This shows that the attractor for the short-term weather evolution in the monsoon region of China exhibits a chaotic mo-tion. The estimate of K2 yields a predictable time scale of about ten days. This result is in agreement with that ob-tained earlier by the dynamic-statistical approach.The effects of the lag time τ on the estimate of D and K2 are investigated. The results show that D and K2 are convergent with respect to τ. The day to day averaged pressure series used in this paper are treated for the extensive phase space with τ = 5, the coordinate components are independent of each other; therefore, the dynamical character quantities of the system are stable and reliable.
Ozone during Stratospheric Warmings at Uccle
V. N. R. Mukku, C. S. Bhosale
1991, 8(2): 251-255. doi: 10.1007/BF02658099
The day-to-day variations in ozone content at Uccle (51oN) during some stratospheric warming events are ex-amined. In particular, the attention is focused on the timing of commencement of ozone enhancement prior to peak day of warming and on the relationship in the ozone content between the upper and lower stratosphere. These two features are compared with the predictions of ozone transport models. There seems to be an agreement between mod-el predictions and observed features in some cases.