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1994 Vol. 11, No. 3

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A Diagnostic Study of Explosive Development of Extratropical Cyclone over East Asia and West Pacific Ocean
Jia Yiqin, Zhao Sixiong
1994, 11(3): 251-270. doi: 10.1007/BF02658144
In this paper, a diagnostic analysis is made for a kind of explosive cyclone over East Asia and the West Pacific Ocean in cold season, using the level III FGGE dataset. The cyclone started developing at 0000 UTC 30 March, 1979.Q vector analysis shows that ageostrophic wind was obvious in cyclone region. The calculation of different kinds of frontogenetical functions indicates that the development of cyclone was closely related to barocunicity, especially, at lower levels.Isentropic analysis revealed the three-dimensional structure of cyclone development, that is, ascent of southerly warmer current and descent of northerly colder current existed around the cyclonic center during the developing pro-cess of the cyclone and is very favourable to the release of available potential energy and generation of eddy kinetic energy.Not only shear component, but also curvature component of upper level jet contributed to the explosive devel-opment of the cyclone.The computation of convergence of moisture flux demonstrated that the moisture probably came from the tropi-cal ocean. The distribution of water vapor supply in this case was very advantageous to the deepening of cyclone, es-pecially, during the well-developing period.Comparison between East Asia-Pacific case and North America-Atlantic case (Ogura and Juang, 1990) has been conducted. The common characteristics were that there existed strong baroclinicity in both cases. However, in the latter case, the latent heat release was of secondary importance and in our case, moisture also played very impor-tant role in certain, stages of the cyclogenesis, especially, during well-developing stage when it moved over oceanic surface.
Optimal Use of High Resolution Infrared Sounder Channels in Atmospheric Profile Retrieval
Li Jun, Huang Hung-Lung
1994, 11(3): 271-276. doi: 10.1007/BF02658145
Due to correlations among high resolution infrared sounder radiances and retrieval computation efficiency, it is prudent to use a set of statistically less correlated channels which not only retains the majority of measurement infor-mation but also yields the most accurate atmospheric profile retrievals. The statistical procedure of these channels se-lection is described in the paper. The use of optimal selected channels simulated for the measurements of AIRS (Atmospheric InfRared Sounder) in the statistical / physical retrieval is discussed. Simulated AIRS inversion results demonstrate the advantages of using optimal channel set that produce the accurate and stable retrieval solution.
Preliminary Study of Reconstruction of a Dynamic System Using an One-Dimensional Time Series
Peng Yongqing, Zhu Yufeng, Yan Shaojin
1994, 11(3): 277-284. doi: 10.1007/BF02658146
This paper concerns the reconstruction of a dynamic system based on phase space continuation of monthly mean temperature 1D time series and the assumption that the equation for the time-varying evolution of phase-space state variables contains linear and nonlinear quadratic terms, followed by the fitting of the dataset subjected to continua-tion so as to get, by the least square method, the coefficients of the terms, of which those of greater variance contribu-tion are retained for use. Results show that the obtained low-order system may be used to describe nonlinear proper-ties of the short range climate variation shown by monthly mean temperature series.
Study on the Thermal Internal Boundary Layer and Dispersion of Air Pollutant in Coastal Area by Numerical Simulation
Jiang Weimei, Yu Hongbin
1994, 11(3): 285-290. doi: 10.1007/BF02658147
In this paper, a scheme on a mesoscale dispersion modeling system was set up. The modeling system was used to study the turbulence structure of TIBL and dispersion features under shoreline fumigation situation. The modeling system has successfully solved the problem of meteorological input of stochastic dispersion models and exploited a new approach to comprehensive application of this kind of dispersion models.
Symmetric Stability of Rotation and Boussinesq Fluid in Bounded Domain by Using Normal Mode Method
Ren Shuzhan
1994, 11(3): 291-295. doi: 10.1007/BF02658148
The stability properties of the equilibria with constant wind shear (both in vertical and horizontal direction) and the non-coastaut static stability in bounded, inviscid and adiabatic atmosphere were investigated by using normal mode method. The results show that the stability property is determined by Richardson number Ri as well as the ab?solute vorticity. When the absolute vorticity F is positive, i.e. F > 0, (where ) the sufficient condition for symmetric stability is and when , the equilibria are unstable for all possible normal mode disturb?ances. In addition, the most unstable growth rate was also obtained here.
Study of the Simultaneous Physical Retrieval Method for Meteorological Parameters over the Continental Plateau of China
Li Guangqing, Dong Chaohua, Zhang Wenjian, Wu Baosuo, Wang Weihe, Wu Zhidian
1994, 11(3): 296-310. doi: 10.1007/BF02658149
It is common knowledge that continental retrieval especially for Qinghai-Xizang Plateau has not been solved to date. In order to explore applicable inverse model and method for continent including the plateau, in this study au-thors use an improved simultaneous physical retrieval method hereafter referred to as the ISPRM, for computing me-teorological parameters from NOAA-10 satellite TOVS data. The retrieval results verified by nearby radiosondes show that the ISPRM is more applicable for the continental plateau.
Winter Asia Jetstream and Seasonal Precipitation in East China
Liang Pingde, Liu Aixia
1994, 11(3): 311-318. doi: 10.1007/BF02658150
The monthly mean geostrophic wind fields for January during 1951-1990 period are calculated by using data of 500 hPa monthly mean height. The relation between Asia Jetstream in winter and the important seasonal precipitation in East China is analysed. The analysis shows that the south branch of jetstream is stronger (weaker) in winter, the rainfall will be more (less) than normal in the subsequent spring in South China, and summer rainfall in North China will be more (less), too; these important rainy seasons are related to each other; the Indian summer monsoon is not only related to the summer rainfall in North China, but also related to the spring rainfall in South China and the south branch of jetstream in winter.
Modelling the January and July Climate of 9000 Years before Present
Wang Huijun
1994, 11(3): 319-326. doi: 10.1007/BF02658151
The January and July climate of 9000 years before present was simulated through a set of perpetual experiments by means of the newly designed 9-Level Atmospheric General Circulation Model (AGCM) in the Institute of At-mospheric Physics (IAP). The results were analysed and compared with previous results simulated by the IAP 2-Level AGCM. There exists good agreement between them. It is found that the temperature is higher in July and lower in January in 9000 yBP than that at present. The temperature difference is more obvious in the Northern Hemisphere than in the Southern Hemisphere and greater in July than in January. These results prove the potential abilities of the 9-L AGCM in the climate simulation and climate prediction.
Estimation of Winds at Different Isobaric Levels Based on the Observed Winds at 850 hPa Level Using Double Fourier Series
S. N. Bavadekar, R. M. Khaladkar
1994, 11(3): 327-334. doi: 10.1007/BF02658152
A technique based on the double Fourier series is developed to estimate the winds at different isobaric levels for the limited area domain, 35oE to 140oE and 30oS to 40oN, using the observed winds at 850 hPa level for the month of June. For this purpose the wind field at a level under consideration is taken in the ratio form with that of 850 hPa level and the coefficients of the double Fourier series are computed. These coefficients are subsequently used to compute the winds which are compared with the actual winds. The results of the double Fourier series technique are compared with those of the polynomial surface fitting method developed by Bavadekar and Khaladkar (1992). The technique is also applied for the daily wind data of 11, June, 1979 and the validation of the technique is tested for a few radiosonde stations of India. The computed winds for these radiosonde stations are quite close to observed winds.
Signatures of a Universal Spectrum for Nonlinear Variability in Daily Columnar Total Ozone Content
A.M.Selvam, M.Radhamani
1994, 11(3): 335-342. doi: 10.1007/BF02658153
Continuous periodogram analyses of sets of 50 to 364 daily mean atmospheric columnar total ozone content at 19 globally representative stations indicate that the power spectra follow the universal inverse power law form of the statistical normal distribution. The results are consistent with prediction of a cell dynamical system model for atmos-pheric flows extending up to the stratosphere and above. The unique quantification for nonlinear variability of daily atmospheric total ozone implies predictability of the total pattern of fluctuations.
A Modeling Study of Climatic Change and Its Implication for Agriculture in China Part I: Climatic Change in China
Dai Xiaosu, Ding Yihui
1994, 11(3): 343-352. doi: 10.1007/BF02658154
The trends and features of China’s climatic change in the past and future are analysed by applying station obser-vations and GCM simulation results. Nationally, the country has warmed by 0.3oC in annual mean air temperature and decreased by 5% in annual precipitation over 1951-1990. Regionally, temperature change has varied from a cooling of 0.3oC in Southwest China to a warming of 1.0oC in Northeast China. With the exception of South China, all regions of China have shown a declination in precipitation. Climatic change has the features of increasing remark-ably in winter temperature and decreasing obviously in summer precipitation. Under doubled CO2 concentration, climatic change in China will tend to be warmer and moister, with increases of 4.5oC in annual mean air temperature and 11% in annual precipitation on the national scale. Future climatic change will reduce the temporal and spatial differences of climatic factors.
A Study of Heavy Rainfall of 8-10 June, 1991 over Maharashtra, India
A.K.Kulkarmi, B.N.Mandal, R.S.Sangam
1994, 11(3): 353-366. doi: 10.1007/BF02658155
A low pressure system from the southwest Bay or Bengal between 8-10 June, 1991 brought heavy and continu-ous rainfall over different parts of Maharashtra. This 3-day heavy rainspell over Maharashtra has been analysed to assess its magnitudes or point as well as areal rainfall. The analysis showed that there were 74 stations which received 3-day total rainfall during 8-10 June exceeding their respective normal June rainfall. The areal raindepths obtained from the rainstorm of June, 1991 have been compared with similar data of past severe rainstorms of the region which showed that June, 1991 rainstorm yielded higher magnitudes of raindepths upto certain size of areas. A relationship has also been developed between point to areal rainfall of this rainstorm for 1-3 day durations for obtaining areal raindepths.
Interactions between the 30-60 Day Oscillation, the Walker Circulation and the Convective Activities in the Tropical Western Pacific and Their Relations to the Interannual Oscillation
Huang Ronghui
1994, 11(3): 367-384. doi: 10.1007/BF02658156
In this paper, interactions between the 30-60 day oscillation, the Walker circulation and the convective activities in the tropical western Pacific during the Northern Hemisphere summer are analyzed by using the observed data of wind fields and high-cloud amounts for the period from 1980 to 1989.The analyzed results show that the 30-60 day oscillation (hereafter called LFO) may be largely affected by the convective activities in the tropical western Pacific. The LFO in the tropical western Pacific during the strong convective activities around the Philippines stronger than those during the weak convective activities around the Philippines. Moreover, in the case of strong convective activities around the Philippines, the LFO in the tropical west-ern Pacific and tropical eastern Indian Ocean generally propagates westward, and it is intensified by the LFO with a westward propagating center of maximum oscillation from the east to 140oE. However, in the case of weak convective activities around the Philippines, the LFO gradually becomes stronger with a eastward propagating center of maximum oscillation from the eastern Indian Ocean to the tropical western Pacific.Corresponding to the 30-60 day oscillation, the Walker circulation is also in oscillation over the tropical Pacific and its circulation cell seems to shift gradually westward from the tropical western Pacific to the tropical eastern In-dian Ocean with strong convective activities around the Philippines. This may maintain the intensification of convective activities there. However, during the weak convective activities around the Philippines, the Walker circula-tion gradually moves eastward and an ascending flow may appear in the equatorial central Pacific. This may cause convective activities to be intensified over the equatorial central Pacific.The analyzed results also show that the LFO in the tropical western Pacific and East Asia may be associated with the interannual oscillation of the SST anomaly in the tropical western Pacific.