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Modeling the impact of Australian Plate drift on Southern Hemisphere climate and environment

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Chinese Science Bulletin 2005年第14期50卷 1495-1502页

作者： ZHOU Botao1,5, ZHAO Ping2, JIAN Zhimin3 & HE Jinhai4.1. Nansen-Zhu International Research Center, institute of atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china 2. institute of Climate and Environment, Chinese Academy of Meteoro- logical Sciences, Beijing 100081, china 3. Laboratory of Marine Geology, Tongji University, Shanghai 200092, china 4. department of atmospheric Sciences, nanjing institute of meteorol- ogy, nanjing 210044, china 5. Graduate School of the Chinese Academy of Sciences, Beijing 100039, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China institute of Climate and Environment Chinese Academy of Meteorological Sciences Beijing 100081 China Laboratory of Marine Geology Tongji University Shanghai 200092 China department of atmospheric Sciences Nanjing Institute of Meteorology Nanjing 210044 China

Using a global atmosphere-ocean coupled model with the present-day and 14.MaB.P. oceanic topogra- phy respectively, two experiments are implemented to inves- tigate the effect of different locations of Australian Plate on the atmospheric circulation in middle-high latitudes of the Southern Hemisphere. The results show that when Austra- lian Plate lay south at 14.MaB.P., both anticyclone circula- tions in the subtropical oceans and cyclone circulation around 60°-70°S are strengthened. Subtropical highs and circumpolar low pressure appear stronger, which results in much stronger Antarctic Oscillation and shorter period of Antarctic Oscillation Index (AOI) at 14.MaB.P. The rainfall and the surface air temperature also change correspondingly. The precipitation decreases around 4.°S and increases around 60°-70°S, and the surface air temperature rises in high latitudes of the South Pacific and descends over the Weddell Sea and its north side. Besides, due to the changes of the temperatures and winds, Antarctic sea ice coverage also changes with its increasing in the Ross Sea and its west re- gions and decreasing in the Weddell Sea.

关键词：半球气候地球环球澳大利亚漂流物海洋地形学

The effects of different sea surface temperature distributions over the western Pacific on the summer monsoon properties

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Acta Oceanologica Sinica 1993年第4期12卷 535-547页

作者： Qian Yongfu department of atmospheric Sciences, nanjing University, nanjing 210008,{4. Dept. of atmospheric Sciences Nanjing Univ. Nanjing 21008 China. China

A modified and improved primitive equation numerical model with p-sigma incorporated vertical coordinates is used to simulate the effects of different sea surface temperature distributions over the western Pacific on the summer monsoon properties. The different sea surface temperature (SST) distributions are automatically generated in the time integrations by using two different SST models, one of which is called the deep ocean model (DOM) and the other the shallow ocean model (SOM). The SST generated by the DOM has the distribution pattern of the initial SST which is similar to the pattern in the cold water years over the western Pacific, while the SST generated by the SOM has the pattern similar to that in the warm water years. The differences between the experimental results by using DOM and SOM are analyzed in detail. The analyses indicate that the most basic and important characteristics of the summer monsoon climate can be simulated successfully in both experiments, that means the climatic properties in the monsoonal climate regions are mainly determined by the seasonal heating, the contrast between the land and the sea, the topography, and the physical properties of the underlying surfaces. However, the differences between the two experiments tell us that the climatic properties in the summer monsoon regions in the cold water year and the warm water year do differ from each other in details. In the warm water year, the thermal contrast between the land and the sea becomes weaker. Over the warm water area, the upward motions are induced and the dynamical conditions favorable for the convective activities are formed, the Somali low-level cross equatorial current is somewhat weakened, while the cross equatorial currents, east of 90°E, are strongly strengthened, the precipitation amount in the tropical regions largely increases, and the precipitation over the coastal regions increases, too. However the precipitation over the southeast china and its coastal area d

关键词： Sea surface temperature anomaly monsoon climate modelling computational models of SST

Numerical study of rapid cyclogenesis over sea

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Acta Oceanologica Sinica 1989年第1期8卷 51-62页

作者： Du Jun and Yu Zhihao department of atmospheric Sciences, nanjing University, nanjing,{4. Dept. of atmospheric Sciences Nanjing Univ Nanjing China. China

A five-layer primitive equation model was used in the study of rapid cyclogenesis over sea. The numerical simulations show that'the Tibetan Plateau, large-scale baroclinicity and heat flux from the sea surface are the three important agents to produce cyclonic vorticity along the east coast of china. The diagnostic computation of a 24.h control simulation indicates that the nonlinear vorticity advec-tion, baroclinicity and diabatic heating are also responsible for the development of the extratropical cyclones over seas.

关键词： Numerical study of rapid cyclogenesis over sea over

Influence of interannual variability of Antarctic oscillation on mei-yu along the Yangtze and Huaihe River valley and its importance to prediction

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Chinese Science Bulletin 2003年第S2期48卷 61-67页

作者： GAO Hui~(1,2), XUE Feng~1 WANG Huijun~1 1. institute of atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china 2. department of atmospheric Sciences, nanjing institute of meteorology, nanjing 210044. china Chinese Acad Sci Inst Atmospher Phys Beijing 100029 Peoples R China nanjing Inst meteorol Dept Atmospher Sci Nanjing 210044 Peoples R China

Both correlation analysis and case study indi-cate that Antarctic oscillation (AAO) is closely related withsummer rainfall in eastern china. When AAO is stronger inboreal spring, especially in May, there is more mei-yu rain-fall in summer with a longer period along the Yangtze andHuaihe River valley. In contrast, there is less rainfall with ashorter period corresponding to a weaker AAO. Besides, ananomalous AAO changes the position and intensity of severalcirculation systems, which are important to summer rainfallalong the Yangtze and Huaihe River valley. Furthermore, theAntarctic sea ice is negatively correlated with the intensity ofAAO with a 6-month leading time. The result in this studyprovides a new method for the prediction of mei-yu.

关键词： Antarctic oscillation interannual variability mei-yu Antarctic sea ice.

Numerical simulation of influence of the anomalies of theCentral-eastern Equatorial Pacific SST and Arctic seaice cover in summer on the atmospheric circulation

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Acta Oceanologica Sinica 1992年第3期11卷 401-411页

作者： Yang Xiuqun and Huang Shisong department of atmospheric Sciences, nanjing University, nanjing 210008,{4.

A series of numerical experiments have been conducted with a perpetual July, nine-level general circulation spectral model to determine the effect of variation of the Arctic sea ice cover extent and the joint effect of anomalies of both the Arctic sea ice cover and the Central-eastern Equatorial Pacific sea surface temperature on the summer general circulation. Results show that the two factors,anomalously large extent of the Arctic sea ice cover and anomalously warm sea surface temperature over the Central-eastern Equatorial Pacific Ocean, play substantially the equal role in the effect on the summer general circulation, and either of them can notably induce the atmospheric anomalies. The main dynamical processes determining the effect of the Arctic sea ice and the equatorial SST anomalies are associated with two leading teleconnection patterns, i. e. the Asia North/American and Eurasian patterns observed in atmosphere. The results presented in this paper again prove that the general circulation is fundamentally motivated by the non-uniform heating between the equator and the pole on the rotating earth.

关键词： Numerical simulation of influence of the anomalies of theCentral-eastern Equatorial Pacific SST and Arctic seaice cover in summer on the atmospheric circulation SST

Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

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Progress in Natural Science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping Fan1,2 and Luo Zhexian2(1. institute of atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china 2. nanjing University of Information Sciences & Technol{4., nanjing 210044, china) institute of atmospheric Physics Chinese Academy of Sciences Beijing 100029 Chin

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 1200 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation

Seasonal variation of global stratosphere-troposphere mass exchange

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Progress in Natural Science:Materials International 2007年第12期17卷 1466-1475页

作者： Guo Dong1,2, Lu Daren2 and Sun Zhaobo1(1. institute of atmospheric Sciences, nanjing University of Information Science and Technology,{4., china 2. LAGEO, institute of atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china) institute of atmospheric Sciences Nanjing University of Information Science and Technology Nanjing 210044 China LAGEO Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

By Wei formula in pressure coordinate, the stratosphere-troposphere mass exchange (STME) is diagnosed globally for 4. years from 1958 to 2001 using the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis datasets. Regions of mass flux into the stratosphere are found over Indonesia, bay of Bangladesh and the mid-west coast of South Africa. Compensating mass outflow from the stratosphere appears mainly over mid-latitudes near large-scale troughs. Upward and downward transport of mass at the middle and high latitudes accompany with each other. Mass flux into troposphere is stronger in autumn and winter than in spring and summer. Strong downward mass flux into the troposphere occurs in eastern Asia the whole year with nearly stable sites. Although the area of eastern Asia accounts for only 5.6% of that of the northern hemisphere (NH), its net mass exchange reaches 15.83% of that of the NH, which means that research on STME of eastern Asia is greatly important to that of the NH and even the global areas. Air across the tropopause enters more from stratosphere to troposphere than that from troposphere to stratosphere, which is possibly related with systematic bias of the assimilated datasets and with persistent rise of the tropopause height. Contributions of the mass exchange and the mass flux exchange in the NH and southern hemisphere (SH) on their latitudes increase from equator to pole, with larger contributions in the NH. Mass exchange and mass flux exchange per areas at high latitudes are larger than that at low latitudes, which means greater mass exchange efficiency at high latitudes.

关键词： stratosphere troposphere mass exchange seasonal variation.

Global dimension and left derived functors of Hom

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Science china Mathematics 2007年第6期50卷 887-898页

作者： Li-xin MAO & Nan-qing DING institute of Mathematics, nanjing institute of Technology, nanjing 211167, china department of Mathematics, nanjing University, nanjing 210093, china institute of Mathematics Nanjing Institute of Technology Nanjing China department of Mathematics Nanjing University Nanjing China

It is well known that the right global dimension of a ring R is usually computed by the right derived functors of Hom and the left projective resolutions of right R-modules. In this paper, for a left coherent and right perfect ring R, we characterize the right global dimension of R, from another point of view, using the left derived functors of Hom and the right projective resolutions of right R-modules. It is shown that rD(R) ? n (n ? 2) if and only if the gl right Proj-dim M R ? n?2 if and only if Ext n?1(N,M) = 0 for all right R-modules N and M if and only if every (n?2)th Projcosyzygy of a right R-module has a projective envelope with the unique mapping property. It is also proved that rD(R) ? n (n ? 1) if and only if every (n?1)th Proj-cosyzygy of a right R-module has an epic projective envelope if and only if every nth Proj-cosyzygy of a right R-module is projective. As corollaries, the right hereditary rings and the rings R with rD(R) ? 2 are characterized.

关键词： global dimension projective resolution envelope 16E10 16E30 16E05

On critical values concerning the evolution of the long period families

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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 494-500页

作者： Xi-Yun Hou1,21 Astronomy department, nanjing University, nanjing 210093, china 2 {4. of Space Environment and Astronautics, nanjing University, nanjing 210093, china Astronomy department Nanjing University institute of Space Environment and Astronautics Nanjing University

In a previous paper, we proposed another special critical value concerning the evolution of the long period family around the equilateral equilibrium points, besides the two values given by Henrard. Are there any other special critical values？ After studying the stability curves of the long period family carefully, we gave a negative answer. During the study, we found an interesting family of periodic orbits which we called the homo family. We studied the evolution of this family following the increase of μ. With these findings, we were able to explain the origin of the four branches of periodic families emanating from L4.and the stability results of the equilateral equilibrium points.

关键词： celestial mechanics