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1993 Vol. 10, No. 2

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The Climatic Effects of the Stratospheric Volcanic Ash
Qian Yongfu
1993, 10(2): 135-146. doi: 10.1007/BF02919136
The climatic effects of the stratospheric volcanic ash are simulated. The model we used is a primitive equation model with the P-σ incorporated coordinate system. The model has 5 layers in the atmosphere and 2 layers in the soil. The volcanic ash is introduced to the first (highest) model layer with a fixed optical thickness of 0.1275. Two comparative numerical experiments with and without the volcanic ash are made. Results show that the effects of the stratospheric volcanic ash on the formations of the mean climatic fields are much smaller than those of the land-sea distribution and the large scale topography. However, it does have contributions to the anomalies of the basic climatic states. The direct effect of the volcanic ash is to increase the temperature in the stratosphere. It can also influence the temperature and the height fields of isobaric surfaces, horizontal and vertical motions, precipitation and the surface climate through dynamic and thermodynamic processes in the atmosphere.
A Study of the Radiation-Climate Effect of Aerosol over Beijing Area
Qiu Jinhuan, Wang Kaixiang
1993, 10(2): 147-154. doi: 10.1007/BF02919137
In this paper, the monthly-averaged planetary albedo and equivalent blackbody temperature are calculated by using Gauss-Seidle numerical model to solve the equation or radiative transfer, based on measured aerosol data over Beijing area. With the increase of atmospheric turbidity, the planetary albedo has different characteristics in different seasons, and there is an evident decrease in the winter season. It means that the local aerosol has an heating effect to the atmosphere in winter. The correlation feature between the surface temperature and the horizontal visibility from 1963 to 1986 is analyzed, and anticorrelation is discovered in winter. It is found that surface temperature increases with the increase of aerosol.
Studies on the Northern Early Summer Teleconnection Patterns, Their Interannual Variations and Relation to Drought / Flood in China
Shi Neng, Zhu Qiangen
1993, 10(2): 155-168. doi: 10.1007/BF02919138
By using the one-point correlation method, calculations have been made of the northern early summer 500 hPa teleconnection patterns. Seven teleconnection patterns are revealed, namely, the Western Atlantic (WA), the Eastern Atlantic (EA), the Eurasian (EU), the Bengal / Northern Pacific (BNP), the Western Pacific (WP), the East Asian / Pacific (EAP), and the Huanghe / East Asian (HEA) patterns. Their centers are determined and their yearly intensity indices (1951-1990) are calculated. On this basis the relationship between their interannual variations and the drought / flood in China is examined. It is noted that the EU, HEA and EAP wave trains are closely related to the drought/ flood in China. The HEA and EAP patterns strongly influence the precipitation in eastern China. For ex-ample, the fierce floods experienced in 1991 early summer over China are related to the weak EAP and strong HEA patterns.
Large Scale Perturbations in Extratropical Atmosphere-Part I: On Rossby Waves
Y. L. McHall
1993, 10(2): 169-180. doi: 10.1007/BF02919139
This study reexamines the propagation mechanism and geostrophic property of the classical two-dimensional Rossby waves in a non-divergent barotropic atmosphere. It will be found that propagation of large scale atmospheric waves depends crucially on horizontal divergence. A small Rossby number in Rossby waves is not sufficient for the waves to have a small ageostrophic component, because the two-dimensional classical Rossby waves do not manifest the geostrophic balance as good as observed in the atmosphere.
Large Scale Perturbations in Extratropical Atmosphere-Part II: On Geostrophic Waves
Y. L. McHall
1993, 10(2): 181-192. doi: 10.1007/BF02919140
We have examined, in Part I, the propagation mechanism and geostrophic property of classical Rossby waves in a non-divergent barotropic atmosphere. As we found that the non-divergent Rossby waves do not propagate in a hydrostatically equilibrium atmosphere, and do not manifest a good geostrophic property, an alternative large scale circulation pattern of geostrophic waves has been proposed (McHall, 1991a). The propagation mechanism and geostrophic property of these waves are examined in the present study.
Quasi-40-Day Oscillation and Its Teleconnection Struc-ture together with the Possible Dependence on Conversion of Barotropic Unstable Energy of Temporal Mean Flow
Xu Jianjun
1993, 10(2): 193-200. doi: 10.1007/BF02919141
A study is made of the distribution of the diagnostic quantity vector E and the teleconnection structure of 30-50 (quasi-40) day oscillation, together with the dependence on the conversion of barotropic unstable energy of mean flow in terms of ECWMF daily 500 hPa grid data in winter, indicating that the energy transportation is closely associated with the westerly jet position, with zonal (meridional) propagation in the strong (weak) wind region, that considerable conversion of barotropic energy occurs at the jet exit region where low-frequency oscillation gains energy from the mean flow, leading to maximum kinetic energy for the oscillation observed there, which is marked by evident barotropy in striking contrast to the baroclinicity at low latitudes and that the teleconnection core is related to the center of action in the atmosphere and bound up with the pattern of the west wind.
Some Preliminary Results on Pilot Study of Global Change in China
Chen Panqin, Yan Zhongwei
1993, 10(2): 201-210. doi: 10.1007/BF02919142
On the basis of existing data and research results the changes of life supporting environment in China in the his-tory are briefly described. The differences between regional climate variations and climate jump are the very impor-tant features and phenomena in estimating the trend of environmental evolution in the future. Finally, it is pointed out that sensitive zone is an ideal place to study global change. Many evidences show that the response of environmental elements in the sensitive zones to global change events is very obvious, so that much attention should be paid to the study of sensitive zone.
Modelling of Indian Monsoon Rainfall Series by Univariate Box-Jenkins Type of Models
S.D.Dahale, S.V.Singh
1993, 10(2): 211-220. doi: 10.1007/BF02919143
The time domain approach, i.e. Autoregressive (AR) processes, of time series analysis is applied to the monsoon rainfall series of India and its two major regions, viz. North-West India and Central India. Since the original time series shows no modelable structure due to the presence of high interannual variability, a 3-point running filter is ap-plied before exploring and fitting appropriate stochastic models. Out of several parsimonious models fitted, AR(3) is found to be most suitable. The usefulness of this fitted model is validated on an independent datum of 18 years and some skill has been noted. These models therefore can be used for low skill higher lead time forecasts of monsoon. Further the forecasts produced through such models can be combined with other forecasts to increase the skill of monsoon forecasts.
A Universal Spectrum for Interannual Variability of Monsoon Rainfall over India
A. Mary Selvam
1993, 10(2): 221-226. doi: 10.1007/BF02919144
Continuous periodogram analyses of 115 years (1871-1985) summer monsoon rainfall over the Indian region show that the power spectra follow the universal and unique inverse power law form of the statistical normal distribution with the percentage contribution to total variance representing the eddy probability corresponding to the normalized standard deviation equal to [(log L/log T50) – 1] where L is the period length in years and T50 the period up to which the cumulative percentage contribution to total variance is equal to 50. The above results are con-sistent with a recently developed non-deterministic cell dynamical model for atmospheric flows. The implications of the above result for prediction of interannual variability of rainfall is discussed.
A Sensitivity Study of IAP AGCM to Radiation Changes: Climate Simulation of 125kyr and 115kyr before Present
Wang Huijun
1993, 10(2): 227-232. doi: 10.1007/BF02919145
The IAP AGCM was used to simulate the climate of 12Skyr and 115kyr before present. We analysed the results and then studied the sensitivity of the model to the changes of radiation distribution induced by orbital parameter changes. The reasonability of the results was also discussed.
Topography and the Non-linear Rossby Wave in the Zonal Shear Basic Flow
He Jianzhong
1993, 10(2): 233-242. doi: 10.1007/BF02919146
Under semi geostropical approximation, by means or phase angle function the non-linear ordinary differential equation is derived involving topography and zonal shear basic flow. Conditions for the existence of limited amplitude periodical and isolated wave solutions are directly obtained based on the qualitative theory of the ordinary differentical equation. Analysis is thus made of the influence of topography and zonal shear flow on the existence of wave solution. Finally, explicit wave solutions are determined by function approaching with the result that topogra-phy and zonal shear flow affect not only the existence but also the form of waves, indicating the non-linear features of waves and the effect of topography and shear basic flow on undulation.
A New Multidimensional Time Series Forecasting Method Based on the EOF Iteration Scheme
Zhang Banglin, Liu Jie, Sun Zhaobo
1993, 10(2): 243-247. doi: 10.1007/BF02919147
In this paper a new multidimensional time series forecasting scheme based on the empirical orthogonal func-tion (EOF) stepwise iteration process is introduced. The scheme is tested in a series of forecast experiments of Nino3 SST anomalies and Tahiti-Darwin SO index. The results show that the scheme is feasible and ENSO predictable.
On the Seasonal Transition and the Interannual Variability in Global Kinetic Energy at 500 hPa, Accompanied with Anomalies of Energy during the 1982 / 83 ENSO
Qiu Yongyan
1993, 10(2): 248-256. doi: 10.1007/BF02919148
Utilizing the material of monthly means of the three primary kinetic energy modes over the whole globe at 500 hPa during the nine years of 1980-1988, both the rapid seasonal changes and the interannual variability in the general circulation in terms of the energy modes have been investigated, with special attention paid to the unusual year 1983. Two main results are obtained. One, there are remarkable seasonal rapid changes over the Northern Hemisphere, oc-curring generally in April and October. The other, among the nine years of 1980-1988, 1983 is the only one with unusual energy modes and remarkably abnormal seasonal changes.
An Elegant Coupled Model
Chanchal Guha-Roy, Dilip Kumar Sinha
1993, 10(2): 257-260. doi: 10.1007/BF02919149
This paper deals with a new family of coupled wave equations which are basically nonlinear in nature. An analyt-ical study enables us to show that these equations exhibit solitary wave profiles. Finally some remarks are drawn from the standpoint of atmospheric problem.