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A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

science China Earth sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2. ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3.1. International Center for Climate and Environment sciences, Institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 10002., China {2., nanjing university of information science and technology, nanjing 210044, China 3. Beijing Institute of Applied Meteorology, Beijing 10002., China 1. International Center for Climate and Environment sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. jiangsu key laboratory of meteorological disaster Nanjing University of Information Science and Technology Nanjing 210044 China 3. Beijing Institute of Applied Meteorology Beijing 100029 China

A new 3.VAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3.VAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 2.-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 42. m reach 0.63. and 0.3. psu.

关键词： data assimilation, 3.VAR, sea surface height, ARGO floats.

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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 {2. {3. of Ministry of Education and College of Atmospheric {3.s, nanjing university of information science and technology, nanjing 210044, China [a]key laboratory of {2. {3. of Ministry of Education and College of Atmospheric {3.s 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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Features of aerosol optical depth and its relation to extreme temperatures in China during 1980–2.01

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Acta Oceanologica Sinica 2011年第2期30卷 33-45页

作者： HU Ting SUN Zhaobo LI Zhaoxin jiangsu key {2. of {3. {3. Nanjing University of Information Scienceand Technology Nanjing 210044 China The Department of Atmospheric science Nanjing University of Information Science andTechnology Nanjing 210044 China Laboratoire de Meteorologie Dynamique CNRS France

Based on Total Ozone Mapping Spectrometer （TOMS） monthly aerosol optical thickness （AOT） measurements in 1980–2.01 a study is made of space/time patterns and difference between land and sea of AOT 0.50 μm thick over China,which are put into correlation analysis with synchronous extreme temperature indices （warm/cold day and night）.Results suggest that 1） the long-term mean AOT over China is characterized by typical geography,with pronounced land-sea *** AOT has significant seasonality and its seasonal difference is diminished as a function of latitude.2. On the whole,the AOT displays an appreciably increasing trend,with the distinct increase in the eastern Qinghai-Tibetan plateau and SW China,North China,the mid-lower Changjiang （MiLY） valley as well as the South China Sea,but marginal decrease over western/northern Xinjiang and part of South China.3. The AOT over land and sea is marked by conspicuous intra-seasonal and -yearly oscillations,with remarkable periods at one-,two-yr and more （as interannual periods）.4） Land AOT change is well correlated with extremely temperature ***,the correlations of AOT to the extreme temperature indices are more significant in Eastern China with 110 ° E as the *** high-correlation regions are along the Southern China coastline,the Loess Plateau and the Sichuan Basin,and even higher in North China Plain and the mid-lower Changjiang River reaches.5） Simulations of LMDZ-regional model indicate that aerosol effects may result in cooling all over China,particularly in Eastern *** contribution of aerosol change may result in more decrease in the maximum temperature than the minimum,with decrease of 0.11/0.08 K for zonal average,respectively.

关键词： aerosol optical thickness extreme temperature index space/time pattern trend correlation

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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 {2. {3. of Ministry of Education and College of Atmospheric {3.s, nanjing university of information {3. & technology, nanjing 210044, China 1. key laboratory of {2. {3. of Ministry of Education and College of Atmospheric {3.s Nanjing University of Information Science & Technology Nanjing 210044 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 3.°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 3.°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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Energy dispersion of complex non-isolated vortices

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

作者： LUO ZheXian 1,2.1 key laboratory of {2. 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 2.403., China key laboratory of {2. {3. of Ministry of Education Nanjing University of Information Science and Technology Wuxi Research Center of Environmental science and technology

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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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 {2. {3. of Ministry of Education Nanjing University of Information Science & Technology jiangsu meteorological Observatory

Based on daily precipitation data from 2.2.stations in East China and NCEP/NCAR daily global final analysis data in June and July from 2.00 to 2.10, 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 3.0-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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Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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science China Earth sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2. DING Yihui3.& ZHANG Renhe2.1. jiangsu {3. {2. of meteorological {3. (KLME), nanjing Institute of Meteorology, nanjing university of Informa- tion science and technology, nanjing 210044, China 2. State {3. {2. of Severe Weather (LaSW), Chinese Academy of meteorological sciences, Beijing 100081, China 3. National Climate Center, Chinese meteorological Administration, Beijing 100081, China 1. jiangsu key {2. of {3. {3. (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing 210044 China 2. State key laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing 100081 China 3. National Climate Center Chinese Meteorological Administration Beijing 100081 China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-China Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-China Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-China Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-China Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-China Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-China Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-China Peninsula to South China Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-China Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

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Spatial teleconnection pattern between Indian Ocean Dipole and the southern high-latitude sea level pressure field

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Progress in Natural science:Materials International 2005年第12期15卷 1143-1147页

作者： LIU Na,CHEN Hongxia,MIN Jinzhong,HUA Feng and BIAN Hongcun jiangsu key {2. of {3. {3.,nanjing university of information science & technology,nanjing 210044,China key {2. of Marine science and Numerical Modeling,State Oceanic Administration,Qingdao 2.6061,China First Institute of Oceanography,Qingdao 2.6061,China jiangsu key {2. of {3. {3. Nanjing University of Information Science & Technology Nanjing 210044 China. key laboratory of Marine {2. and Numerical Modeling State Oceanic Administration Qingdao 266061 China. First Institute of Oceanography Qingdao 266061 China

Sea level pressure (SLP) anomalies over the southern high latitudes associated with the Indian Ocean Dipole Mode (IOD) are *** correlation and composite analysis depict,for the first time,the seasonal spatial variability in the relationship of SLP field in Southern Ocean with *** suggest that the IOD signal exists in the southern high latitudes and it is enhanced in boreal autumn,an active season of *** interannual to subdecadal timescales,the spatial teleconnection pattern exhibits a wavenum-ber-3.pattern around the circumpolar Southern Ocean and the lead-lag correlation analysis shows that there are about 3.months of SLP anomalies in southern high latitudes lagging IOD,which indicates that the response time is almost instantaneous.

关键词： IOD SLP teleconnection southern high latitudes

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ANALYTICAL SOLUTION OF NONLINEAR BAROTROPIC VORTICITY EQUATION

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Journal of Hydrodynamics 2008年第4期20卷 530-535页

作者： WANG Yue-peng SHI Wei-hl College of Mathematics and Physics Nanjing University of Information Science and Technology Nangjing210044 China jiangsu key {2. of {3. {3. Nangjing University of Information Science and Technology Nangjing 210044 China Department of Mathematics Shanghai University Shanghai 200072 China

The C^k （k ≥ 3. stability of nonlinear barotropic vorticity equation was proved. The necessary and sufficient conditions for the initial value problem to be well-posed were presented. Under the conditions of well-p... 详细信息

关键词： nonlinear barotropic vorticity equation stability well-posedness analytical solution

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Turbulent intensity and its similarity function over an Inner Mongolian grassland during spring

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science China Earth sciences 2010年第5期53卷 773-780页

作者： YUE Ping1,2.3. NIU ShengJie2. HU YinQiao4 & ZHANG Qiang1 1 key {3. of Arid Climate Change and Reducing {2. of Gansu Province, key {3. of Arid Climate Change and Reducing {2. of CMA, Institute of Arid Meteorology, CMA, Lanzhou 73.02., China 2.6}, nanjing 210044, China 3.Zhangye National meteorological Observatory, Zhangye 73.000, China 4 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of science, Lanzhou 73.000, China 1. key laboratory of Arid Climate Change and Reducing {2. of Gansu Province Key Laboratory of Arid Climate Change and Reducing Disaster of CMA Institute of Arid Meteorology CMA Lanzhou 730020 China2. Nanjing University of Information Science and Technology Nanjing 210044 China3. Zhangye National Meteorological Observatory Zhangye 734000 China4. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Science Lanzhou 730000 China

Macroscopic reason for the development of turbulences in fluid is the conjunction action of velocity and temperature shears. We use the 2.08 spring flux observations in the surface layer over Inner Mongolian grassland, obtain the similarity functions of turbulent intensity under different stratification stability conditions, and calculate the clear day turbulent intensity in the spring, which is then analyzed and compared with the observed values of turbulent intensity. The results show that in the Inner Mongolian grassland, under the condition of spring unstable stratification of the surface layer, dependence of the similarity function of turbulent intensity on stratification stability follows a "2.3.power law". The structural function is a constant under the neutral stratification condition, and complicated under the stable condition. The calculated turbulent intensity has a close correlation with the observed one, which verifies the accuracy of the similarity functions and the suitability of the theorem of turbulent intensity in the grassland region.

关键词： turbulent intensity variance of velocity similarity function grassland

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