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Energy dispersion of complex non-isolated vortices

Chinese science Bulletin 2011年第25期56卷 2713-2717页

作者： luo zhexian 1,2 1 key laboratory of meteorological disaster of ministry of education, nanjing university of information science and technology, nanjing 210044, china 2 Wuxi Research Center of Environmental science and technology, Wuxi 214031, china key laboratory of meteorological disaster of ministry of education Nanjing University of Information Science and Technology Nanjing China Wuxi Research Center of Environmental science and technology Wuxi China

Energy dispersion is a fundamental scientific problem in the study of natural disasters such as typhoons, heavy rain and earthquakes. The problem has been addressed by both multi-discipline research and forecast studies. The dynamics of isolated circular vortex energy dispersion have been solved. However, the disastrous results of typhoons and heavy rain often occur due to non-isolated circular vortices, the dynamics of which are explored in this paper. The energy dispersion characteristics of non-isolated vortices with complex structural patterns are examined using a linearized nondivergent barotropical vorticity equation model. In the initial field, a tropical cyclone (TC) vortex and a meso-scale vortex coexist, forming a complex structural pattern. An analytic solution based on a Fourier transform and simulations using a two-dimensional model show the following. (1) A wave train of TC-G-D may be created by the energy dispersion where the line connecting the three member centers of the wave train is parallel to the x axis in the case of an initial TC vortex without a meso-scale vortex. (2) A wave train of TC-G-D may also be created by energy dispersion. However, the line connecting the three member centers of the wave train would no longer be parallel to the x axis. Instead, they would form a triangle in the presence of the initial TC vortex with the meso-scale vortex. (3) There is a nonlinear relationship between the initial intensity of the meso-scale vortex and the base angle of the triangle. These results have the potential to be applied in the field of typhoon forecasting.

关键词：能量色散非隔离式旋涡非线性关系中尺度涡台风预报结构模式傅立叶变换

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On the interannual variation in spring atmospheric inter-hemispheric oscillation linked to synchronous climate in china

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Progress in Natural science:Materials International 2009年第9期19卷 1125-1131页

作者： Chuhan Lu, Zhaoyong Guan * key laboratory of meteorological disaster of ministry of education and College of Atmospheric sciences, nanjing university of information science and technology, nanjing 210044, china key laboratory of meteorological disaster of ministry of education and College of Atmospheric sciences Nanjing University of Information Science and Technology Nanjing 210044 China

Based on NCEP/NCAR monthly mean reanalysis data and surface observations of Chinese stations, inter-hemispheric oscillations (IHO) of spring atmospheric mass on an interannual basis in conjunction with the linkage to the synchronous climate over china are studied. Results suggest that the spring IHO exhibits a significant seesaw pattern for air mass at bi-hemispheric mid-high latitudes, with a consistent vertical circulation structure. The EOF decomposition of zonally mean surface pressures without signals of Arctic Oscillation (AO) and Antarctic Oscillation (AAO) indicates that the EOF1 IHO feature is remarkable, with the corresponding time coeficients correlated with the spring IHO index (IIHO) at 0.93; the spring IHO bears a close relation to the synchronous climate in china, showing the surface pressure, temperature and relative humidity over the country to be in good correlation with IIHO; the spring duststorms in Qinghai, Gansu, Shaanxi and Inner Mongolia have bearing on IHO. Positive-phase IIHO promotes the strengthening of the Siberian high, during which zonal winds between 60°E and 150°W show a longitudinal teleconnection structure extending from the Arctic to Antarctica, leading to positive westerly wind anomalies over Asia, affecting the spring climate of china.

关键词： Air mass Inter-hemispheric oscillation (IHO) Spring climate china

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Interhemispheric atmospheric mass oscillation and its relation to interannual variations of the Asian monsoon in boreal summer

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science china Earth sciences 2010年第9期53卷 1343-1350页

作者： LU ChuHan, GUAN ZhaoYong & CAI JiaXi key laboratory of meteorological disaster of ministry of education and College of Atmospheric sciences, nanjing university of information science & technology, nanjing 210044, china key laboratory of meteorological disaster of ministry of education and College of Atmospheric sciences Nanjing University of Information Science & Technology Nanjing China

Using NCEP/NCAR reanalysis and precipitation records of Chinese stations, we have investigated the relationship of interhemispheric oscillation of air mass (IHO) with global lower-level circulation and monsoon anomalies in boreal summer. Our results show that the summer IHO explains a greater portion of variance in the abnormal distribution of atmospheric mass over 30°S-60°N as well as the Antarctic. The IHO strongly correlates to the variations of sea level pressure (SLP) in these regions. It is shown that IHO has some influences on both atmospheric mass transports and water vapor fluxes over 30°S-60°N in association with three anomalous cyclonic circulations over land areas of the eastern hemisphere, which is in close relation to the changes in summer monsoon intensity in eastern Asia and western Africa. Composites of summer rainfall anomalies in china for high and low IHO-index years indicate that the eastern Asian summer monsoon is more intense, with positive precipitation anomaly centers in northern and northeastern parts of china, as opposed to the negative center over the mid-lower reaches of the Yangtze River (MLRYR) in stronger IHO years. In weak IHO years, a feeble summer monsoon appears in eastern Asia, leading to positive center of precipitation anomalies displaced into the MLRYR. Furthermore, a teleconnection in wind fields between the western African and eastern Asian monsoon regions was observed in the middle and higher troposphere in the scenario of IHO. The anomalous cyclonic (anticyclonic) circulations along the path of this Africa-East Asia teleconnection were found to be just over the diabatic heating (cooling) centers, suggesting that diabatic forcings are responsible for the formation of this Africa-East Asia teleconnection.

关键词： interhemispheric oscillation Asian monsoon precipitation china boreal summer

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Climatological Characteristics of Frontogenesis and Related Circulations over East china in June and July

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Acta meteorologica Sinica 2013年第2期27卷 144-169页

作者：侯俊管兆勇 key laboratory of meteorological disaster of ministry of education Nanjing University of Information Science & Technology Jiangsu meteorological Observatory

Based on daily precipitation data from 212 stations in East china and NCEP/NCAR daily global final analysis data in June and July from 2000 to 2010, the climatological characteristics of frontogenesis and related circulations have been analyzed. The results demonstrate that frontogenesis function distributes non- uniformly in East china. The different terms of the kinematic frontogenesis show different intensities and distributions of frontogenesis. The strongest frontogenesis integrated from different kinematic frontogenesis terms is observed in the Jianghuai area. Frontogenesis events are separated into four types as per the different shear and convergence types of horizontal wind along the strong frontogenesis band at 850 hPa. The four types include the warm shear type, cold shear type （with two subtypes）, west wind convergence type, and east wind convergence type. The events in different frontogenesis types occur with different frequencies over the past decade. The warm shear type occurs most frequently. Different types of frontogenesis have distinctive horizontal and vertical structures. Strong frontogenesis is featured with 340-K contour of 0se parallel to the frontal zone in the vertical. Varied large-scale circulation patterns manifested in shifted location and strength of cyclone or anticyclone, wind convergence, as well as vertical circulation structure are associated with different types of frontogenesis. Moreover, a strong positive correlation between frontogenesis and precipitation is found, i.e., the stronger the frontogenesis, the more precipitation there is. Daily precipitation related to the warm shear type frontogenesis is the largest, and often occurs inside the frontal zone with the same orientation with the strong frontogenesis belt. The second largest daily precipitation occurs with the cold shear type frontogenesis, and related rainfall is usually observed to the south of the frontal zone, with the rain belt extending northeastward. Precipitat

关键词： frontogenesis circulation pattern precipitation East china boreal summer

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Sufficient and necessary conditions for Lyapunov stability of Lorenz system and their application

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science china(information sciences) 2010年第8期53卷 1574-1583页

作者： luo Qi 1 , LIAO XiaoXin 2 & ZENG ZhiGang 2 1 College of information and Control, nanjing university of information science and technology, nanjing 210044, china 2 Department of Control science and Engineering, Huazhong university of science and technology, Image Processing and Intelligent Control key laboratory of education ministry of china, Wuhan 430074, china College of information and Control Nanjing University of Information Science and Technology Nanjing China Department of Control science and Engineering Huazhong University of Science and Technology Image Processing and Intelligent Control Key Laboratory of Education Ministry of China Wuhan China

The sufficient and necessary conditions for Lyapunov stability of the zero equilibrium point of Lorenz system are discussed, and some brief criteria are presented for globally exponential stability, globally asymptotical stability and instability. Furthermore, the behavior of the non-zero equilibrium point of Lorenz system is also investigated, and several sufficient and necessary conditions are provided for locally exponential stability and instability. The established theorems in this paper develop and extend the existing achievements on Lyapunov stability of Lorenz system. In conclusion, by applying the obtained results, some less conservative feedback-control laws are derived to guarantee the globally exponential stability of the chaos control of Chen system, Lu¨ system, Yang-Chen system and Yu-Xia Li system.

关键词： Lorenz system Lyapunov stability sufficient and necessary condition bifurcation values globally exponential synchronization

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Correlation of Dust Storms in china with Chlorophyll a Concentration in the Yellow Sea between 1997-2007

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Atmospheric and Oceanic science Letters 2012年第2期5卷 140-144页

作者： TAN Sai-Chun 1,2 and SHI Guang-Yu 1 1 State key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of sciences,Beijing 100029,china 2 key laboratory of meteorological disaster of ministry of education,nanjing university of information science and technology,nanjing 210044,china State key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China key laboratory of meteorological disaster of ministry of education Nanjing University of Information Science and Technology Nanjing 210044 China

Based on daily observation data at 222 meteorological stations in china,the characteristics of dust storms between 1997 and 2007 were ***,the relationship between dust events and chlorophyll (Chl) a concentration in the Yellow Sea was *** were six regions with high annual frequencies of dust *** seasonal distribution of dust storms showed spatiotemporal *** six regions with highest annual frequencies also exhibited high frequencies of dust storms in *** storms in most regions occurred in *** all dust storms in china,sixty-five percent of all dust storms occurred during the *** area and frequency of dust storms were smaller in fall and winter than in spring and summer.A significant correlation was found between dust events and Chl a concentration in the Yellow *** correlation regions included Qinghai-Xizang region,part of the Hexi Corridor,the western Inner Mongolia and Hetao Regions,and the Hunshandake *** high correlation may be induced by the high ratio of dust storms in the abovementioned regions that arrive over the Yellow Sea,as inferred through a forward trajectory analysis;especially notable is dust transported at a lower altitude (< 3 km).

关键词： dust storm spatial distribution seasonal variation chlorophyll Yellow Sea

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Fuzzy dynamic characteristic model based attitude control of hypersonic vehicle in gliding phase

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science china(information sciences) 2011年第3期54卷 448-459页

作者： luo Xiong 1,2 & LI Jiang 1 1 Department of Computer science and technology, key laboratory of Advanced Control of Iron and Steel Process (ministry of education), university of science and technology Beijing, Beijing 100083, china 2 National laboratory of Space Intelligent Control, Beijing 100190, china Department of Computer science and technology Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology Beijing Beijing China National laboratory of Space Intelligent Control Beijing China

The intelligent autonomous control of hypersonic vehicles has aroused great interest from the field of spacecraft. To solve the problem of longitudinal attitude control of hypersonic vehicle in gliding phase, a new intelligent controller is proposed in this paper. This new controller is based on the fuzzy dynamic characteristic modeling method. The fuzzy logic is introduced into the characteristic modeling by dividing the whole restriction range into several subspaces. Simulations show that this modification greatly improves the performance of the original method. With the same whole restriction range the fuzzy dynamic characteristic modeling decreases the time of convergence, and at the same time makes the attitude angle tracing more precise and robust. Since the sub-model is a characteristic model that has stronger adaptiveness than a fixed local model, the number of fuzzy rules is greatly reduced. Our model sharply reduces the complexity in constructing a fuzzy dynamic model. Finally, simulation results are given to show the effectiveness of the proposed approach in dealing with the attitude control problem of hypersonic vehicle in gliding phase.

关键词： hypersonic vehicle gliding attitude control fuzzy dynamic characteristic modeling

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Review and Discussion on the Plum Rain Research in china

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meteorological and Environmental Research 2011年第3期2卷 25-29,32页

作者： HUANG Zhen,XU Hai-ming,HU Jing-gao Provincial and ministry of education key laboratory for the meteorological disaster,nanjing university of information science & technology,nanjing 210044,china

[Objective] The research aimed to review the research progresses and the research achievements of plum rain in china.[Method] By using the precipitation,the sunshine data in the related observatories during 1961-2009 and the daily height field data of NCEP/DOE2 in 1996,which were provided by the National meteorological information Center,the prior researches about the plum rain in china were reviewed from the division of plum rain,the range of plum rain area and the space distribution.[Result] The formulation of an objective,unified plum rain division standard needed the further research and discussion,which provided the basis for the determination of plum rain range in *** the division of plum rain period,when the sunshine duration parameter was considered,the division of plum rain period could be more *** climatic mean result showed that the plum rain phenomenon still existed in the southwest part of Hubei Province where was in the west of Yichang,and the plum rain range could extend westward a *** the northwest part of the traditional plum rain area,the plum rain phenomenon wasn’t significant,and it didn’t belong to the plum rain range in *** rain and the plum rain in central Hunan,central Jiangxi and central south of Zhejiang should be differentiated by the objective and unified plum rain standard.[Conclusion] Chinese scholars still had some controversies about the typing of plum rain in *** selections of suitable analytical method and region had the important effects on the plum rain typing.

关键词： Plum rain division Plum rain range Plum rain typing china

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Interannual Changes of Tropical Cyclone Intensity in the Western North Pacific

Interannual Changes of Tropical Cyclone Intensity in the Wes...

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第28届中国气象学会年会

作者： Haikun Zhao Liguang Wu and Weican Zhou key laboratory of meteorological disaster of ministry of education nanjing university of information science and technology nanjing 210044

The individual contributions of changes in sea surface temperature（SST）,vertical wind shear and tropical cyclone（TC） tracks to the interannual TC intensity change in the western North Pacific（WNP） basin are examined based on the selected 7 warm years and 7 cold years during the period *** selected warm and cold years are defined by the Nino-3.4 SST anomalies index,corresponding to the El Ni o and La Ni a events,*** intensity model used in this study can simulate the spatial distribution and differences of TC intensity when the model is integrated along the observed TC tracks in the warm and cold *** is found that the change of TC tracks plays a dominant role in the observed TC intensity difference between the warm and cold *** the warm years,TC formation is enhanced in the southeast quadrant,and more TCs take a northwestward track during the warm years than during the cold years because of the interannual change in the large-scalesteering *** a result,more TCs have longer time for intensification and develop into intense TCs during the warm years than during the cold years.

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Tropical Cyclone Intensity Change in the Western North Pacific:Downscaling from IPCC AR4 Experiments

Tropical Cyclone Intensity Change in the Western North Pacif...

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强化科技基础推进气象现代化——第29届中国气象学会年会

作者： Chao Wang and Liguang Wu key laboratory of meteorological disaster of ministry of education,nanjing university of information science and technology,nanjing,china

The influence of global warming on tropical cyclone(TC) intensity has been discussed extensively over the past decade and downscaling studies have been conducted by embedding high-resolution regional models in the large-scale environment derived from global warming experiments in previous *** theoretical models for TC movement and intensity,this downscaling study examines the impact of global warming on TC intensity in the western North Pacific basin with attention to the selection of climate models for the Intergovernmental Panel on Climate Change(IPCC) fourth assessment *** contributions of SST,vertical wind shear and TC track change to TC intensity change are also *** synthetic TC activity in the study is simulated with motion and intensity models,respectively,while little change is assumed in TC formation due to uncertain predictions of regional changes in future TC *** downscaling models are first evaluated against the observations during 1965-1999,and then ten IPCC models are selected based on the TC intensity downscaled with the large-scale environments from their control *** an increase of 1.6-3.5 K in SST over the period 2065-2099,the TC peak intensity and the number of intense TCs are projected to increase by 14% and 66%,respectively,in agreement with previous *** is to say,it is likely that intense TC numbers in this region will increase in a warmer world unless the future TC frequency decreases considerable in the western North Pacific *** SST warming plays a dominant role in affecting TC intensity in most of the climate models,this study suggests that changes in vertical wind shear and prevailing tracks can have significant influence on TC intensity change,sometimes comparable to or even larger than the SST ***,changes in TC track and in vertical wind shear do not have the same systematic effect on TC intensity changes as SST does,increasing the uncertainty of the projection

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