Shi Neng , Zhu Qiaingen , Gu Wenbao , Huang Jing
1994, 17(1):1-10.
Abstract:With the one point correlation method.calculations are made for mid summer 500hPa teleconnection patterns,revealing that there exist seven in July and six in August with their centers located and their yearly intensity indices(1951~1990)calculated. The interannual and intermonthly variations are examined. It is shown that the East Asian/Pacific(EAP)and Northern American East/West(NAEW)pattern in July and the EAP and Eurasian(EU) patterns in August are closely related to mid summer monsoon rainfall in China. The weak EAP in 1991 is an important factor of the severe flooding over Jianghuai Valley of that year.
1994, 17(1):11-19.
Abstract:Startinig from the quasi-geostrophic barotropic vorticity equation .a new bi-time scale scheme is proposed and obtained for the first time are the coupled equtions of 4-wavequasi-resonance for the barotropic wave motion .i. c.. the Landau equations in a broad sense .And with the aid of new conservative quantities. the very low frequency periodic solution of the equations is found with the period of about one year. This can be regarded as a new phys-ical mechanism of interannual oscillation in the real atmosphere. Besides. the wave vectors of 4-wave quasi-resonance are also obtained in this paper.
1994, 17(1):20-26.
Abstract:Finite amplitude ultra-long waves tinder the effect of heat source are studied.The conditions for the existence of finite amplitude periodicity and solitaryperiodicity ultra-longwaves are obtained based oi1 the Hamilton’s function and total energy variation.followed bythe wave analytical solution found by use of Hamilton function for motion invariance and function approximation.It is noted that there is no solitary wave:solution for these ultra-long waves nor constraints of horizontal divergence without the effect of heat source and vice versa.
Shou Shaowen , Li Shenshen , Wang Xin
1994, 17(1):27-31.
Abstract:Diflgnosis is done of kinetic energy (KE)balance and conversion of synoptic and mesoscale perturbation KE of an onland typhoon its external raingush and environment.Theconversion of KE from the synoptic into mesoscale motion is also discussed.Results showthat frictional dissipation and horizontal export of KE are important energy sinks for the typhoon. In its decaying KE grows in the external torrential rain area and the KE productionterm Gk represents the chief energy source for the torrential rain. The growth of Gk may berelated to the development of the torrential rain catiscd by the conversion of synoptic KE intomesoscale perturbation KE.
Ruan Junshi , Shi Neng , Wang Yongzhong
1994, 17(1):32-37.
Abstract:Synthetice contrast is carried out of some of the meteorological conditions over themid-west Pacific close equatorial area and the Northern Hemispheric circulation features inthe previous period of the 1958~1985 El Niño and anti-El Niño events with higher than moderate intensity, Restilts show a sharp difference between the two,which is helpful in the monitoring and predicting of the occurrence of El Niño.
Wang Jianhong , He Jinhai , Miao Chunsheng
1994, 17(1):38-43.
Abstract:A study is made of the stratospheric sudden warming (SSW)in the winters of1983~1984 and 1985~1986.Revealing that the SSW is marked by a 30~60 day intraseason-al low-frequency oscillation. Comparison of the features of tempcrature pressure fields asso-ciated with the SSW period and the anti-SSW one shows a circulation anomaly not only in thelower stratosphere but in the middle troposphere where its behavior seems even more obvi-ous.The low-frequency cycling polar vortex pattern and the circulation meridionalities at ex-tratropical and middle low latitudes and location of midlatitude westerly jet stream center ex-hibit corresponding variation to the low-frequency cycling in relation to SSW and anti-SSWmatched variation.
1994, 17(1):44-50.
Abstract:The apparent heat sotirce(Q1)and apparent moisture sink(Q2)over African mon-soon area(AMA),Indian monsoon area(IMA),South China Sea monsoon area(SCSMA)andsubtropical monsoon area(SMA)have been calculated.based on ECMWF/WMO data fromMay to September of 1986.The results show that quasi-40-day periods of Q1 and Q2 over bothAMA and IMA,quasi biweekly over SCSMA and about 8-day of Q1 and Q2 over SMA,quasi-40-day period are also important signals over SCSMA and SMA. Quasi-40-day oscillations ofQ1 and Q2 over IMA are much stronger than those over the others, The oscillation phase of Q1is ahead of that of Q2 over AMA,but with a homophase for Q1 and Q2 over other monsoon ar-eas. The dipole distribution of low frequency oscillations of Q2 and zonal wind in the low tro-posphere is found over IMA and SCSMA. The low frequency component of Q2 corresponds tolatent heat source(sink),or apparent moisture sink(source)as the low frequency monsoonbecomes active(inactive)over the monsoon areas.
1994, 17(1):51-57.
Abstract:Filtering technique. extended empirical orthogonal function (EEOF).spectrumand correlation analyses have been employed to study the relationship between Arctic ice cover(AIC)and monthly mean temperature and precipitation in China. The curve of power spectrum density shows that not only a semiannual and an annual oscillation but a quasibiennial oscillation can be found in AIC area index anomaly. especially in June, September and November.One can also see that there exists a close relation between the global ENSO events andAIC area low-frequency filtering curve. Analysis based on EEOF of AIC and the monthlymean temperature over China exhibits a good matching which is even better in the later period.The correlation analysis indicates that the variation of AIC area has some influence on the temperature and precipitation in subsequent months over China. In addition, it experiences aquasi-biennial low-frequency oscillation and displays some kind of propagation.
1994, 17(1):58-63.
Abstract:By using a five-layer primitive equation model in the p-σ incorperated coodinates,astudy is made of the relationship between the East Asian winter monsoon and the forcedwaves excited by the convective heat source associated with the low-frequency change ofAustralian summer monsoon. Experimental results indicate that the low frequency changecan cause the LFO of the Northern subtropical upper and low level circtilation,east-westWalker circulation,meridional circulation and cross-equatorial flow,Its oscillation period andintensity are related to those of the heat sotirce. Besides,the low frequency heat source canexcite the northward disttirbance,resulting in the LFO of the stibtropical cicrulation and sub-tropical west wind jet in the Northern Hemisphere. Six days or so after the onset of Australian summer monsoon East Asian winter monsoon can have a strengthening process。However,the lull of the Australian monsoon has no impact on the East Asian winter monsoon.
Chen Wanlong , Chen Jiang , Chen Yuneng , Pen Jiayi
1994, 17(1):64-72.
Abstract:A model with vegetation effect parameterized is developed for studying lake-landbreeze. The dynamic framework is the improved meso-β scale model of Nickerson et al.(1979)in which the soil model by McCumber et al.(1981)and the vegetation parameteriza-tion scheme by Deardorff(1978)are included.Then,the governing system is closed by usingthe ttirbulence parameterization of Therry et al. (1983) and the improved radiation parame-terization by Mahrer et al.(1977).FInally,a sensitivity experiment is conducted in the lake-land breeze of Lake Taihu to the change of the vegetation cover asgire, It is shown that the vegetation coverage has an obvious influence on lake-land breeze.
1994, 17(1):73-78.
Abstract:The analysis of orthogonal rotational factor tinder maximum variance is made ofthe standardised annual rainfall series of China over the past 40 years for objective demarca-tion of regions. Results show that 10 regions can be found.each marked by a dryness/wetnesstrend typical of its own. For example,the drying treidis most noticeable in North China andthe mid to upper reaches of the Huanghe,some degree of wetting is found in NW China,theHuaihe and the mid to upper catchment of the Changjiang and.vibration occurs in the long-term trend of the mid-lower Changjiang. NE China, the Zhujiang basin and S China coastalareas.The rainfall in 1980s is a bit less than that of 1950s.
Chen Weimin , Yu Fan , Yao Yeqing
1994, 17(1):79-85.
Abstract:In the context of Meiyu front cloud features the GMS visible and infrared channel numerical data are employed to obtain the relationships between stich factors as the clotid topinfrared count(IRC).visible light cotint(VISC)and infrared count gradient.on one side. andthe precipitation of the upper-level altocumulus,multilayer clud and cumulonimus on theother,with the aid of stepwise regression. Comparison made of the estimated results to thetheoretic and observed rainfall shows that this method is quite satisfactory.The estimation isbetter in the presence of cloud classification than that of no-cloud classification.
Wang Jianzhong , Yan Shaojin , Peng Yongqing
1994, 17(1):86-92.
Abstract:The present paper has calculated out the chaotic characteristic quantities of the 500hPa day-to-day geopotential height time series of eleven representative observation sta-tions in East Asia in 1979~1988.Results show that the corresponding incidence dimensional-ity is fractional,positive,zero and negfltive valties all exist in the complete Lyapunov expo-nential spectrum, with the sum of the Lyapunov exponents(Σλk)less than zero. Therefore.on the whole,the weather attractor in relation to East Asia is supported by a limited space. The system mean K entropy displayed by the weather attractors of East Asia is about0.1008.Thus,the predictable period is about 9. 92 days. Generally speaking,the predictable period in the northern part of the area is a bit longer.
Zhou Ying , Shen Shuanghe , Zhang Hongwei
1994, 17(1):93-96.
Abstract:The effect of atmospheric stability has been considered in calculating ET fromfields bv Penman-Monteith method.By introducing the equation of the lndex of Agreement,the effect on accuracies of ET calculations with and withotit adjustment of the stability havebeen examined.Results show that the. accuracy of the calculation by the revised equation is sharply reduced with the mean absolute error increased by as > 100%.Therefore,it is feasible to neglect the correction of atmospheric stability in calculating ET. The result is in agreement with the reference(2)conclusion.
1994, 17(1):97-100.
Abstract:The globality and diabatics of long-range weather processes have drawn the attention of meteorologists to the study of the properties and evolution of atmospheric circulation in a new way.represented in recent years by research with symmetry and asymmetry theory.For this purpose,a dynamic forecasting scheme and a statistical forecasting one are proposed with calculations done for the latter. Results show that it is likely to be a new approach to medium and long range weather forecasting.
Wang Zhenhui , Ding Yuguo , Zhou Shengpeng
1994, 17(1):101-109.
Abstract:On the basis of Ref.[1].has first introduced the PRESS criterion for the optimun subset in modern regression analysis to set up the optimum retrieval equation for atmospheric remote sensings. Further more the ridge regression analysis is used in the assessment of the optimum subsets obtained in terms of different different criteria of methods. And the results are verified by actual data.
Zhu Suofeng , Zhao Ming , Pan Yuqiang , Wu Zuchang
1994, 17(1):110-116.
Abstract:The surface mesoscale structures of two cases heavy rain from Meiyu front areanalysed in detail. The characteristics of the heat flux and momentum flux in the boundary layer at different stages of the rainfull are revealed by the data from an extensive-observation tower andlow level radiosonde data.
1994, 17(1):117-124.
Abstract:Nearly one hundred digitized cloud picture samples have been examined based onspectral characteristics at different bands of infrared and visible lights for all kinds of clouds. In the infrared-visible light 2D spectra characteristic space are determined the location of lo-cation of cloud grouping distribution corresponding to the type of clotid from which the sevenmain cloud system including cumulonimbus. thin/thick currus. middle andlow-level eloud,cumulus congestus and multilevel cloud system and the clear sky area have been recognized.Further research has been made on the pattern and form of the various clouds in the high fre-quency distribution area in the characteristic space.
1994, 17(1):125-133.
Abstract:This paper deals mainly with the problem of existence and decay of the global so-lution of a nonlinear degenerated parabolic equation system. The main results are: if αij<pi-1(i,j=1.m) and ui0(x)∈Lp0-2(Ω),then, (E1)admits a global solution u(x,t),and if αij>pi-1(i,j=1.m) and ui0(x)∈Lp0-2(Ω),then,there exists d>0 such that ||ui0||p0-2<d0(i=1.m), the problem(E1)admits a global solution u(x,t).
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