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Statistical distribution of nonlinear random wave height

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Science china earth {2. 2006年第4期49卷 443-448页

作者： HOU Yijun1, GUO Peifang1,2. SONG Guiting1,2. SONG Jinbao1, YIN Baoshu1 & ZHAO xixi1,2.1. institute of Oceanology, chinese Academy of {2., Qingdao 2.6071, china 2. Graduate University of the chinese Academy of {2., Beijing 100039, china 1. institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China 2. Graduate University of the chinese Academy of sciences Beijing 100039 China

A statistical model of random wave is developed using Stokes wave theory of water wave dynamics. A new nonlinear probability distribution function of wave height is presented. The results indicate that wave steepness not only could be a parameter of the distribution function of wave height but also could reflect the degree of wave height distribution deviation from the Rayleigh distribution. The new wave height distribution overcomes the problem of Rayleigh distribution that the prediction of big wave is overestimated and the general wave is underestimated. The prediction of small probability wave height value of new distribution is also smaller than that of Rayleigh distribution. Wave height data taken from East china Normal University are used to verify the new distribution. The results in- dicate that the new distribution fits the measurements much better than the Rayleigh distribution.

关键词： Random ocean wave, nonlinearity, wave height distribution.

The species diversity of fusulinaceans and high-frequency sea-level changes in the Carboniferous-Permian boundary section at xikou, Zhen'an County,Shaanxi Province, china

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Science china earth {2. 2006年第7期49卷 673-683页

作者： ZHANG Haijun1, WANG Xunlian2. DING Lin1, xiA Guoying3 & WANG Lei2.1. institute of Tibetan Plateau Research, chinese Academy of {2., Beijing 100085, china 2. Faculty of earth {2. and Mineral Resources, china University of Geo{2., Beijing 100083, china 3. Tianjin institute of Geology and Mineral Resources, Tianjin 300170, china 1. institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Faculty of earth sciences and Mineral Resources China University of Geosciences Beijing 100083 China 3. Tianjin institute of Geology and Mineral Resources Tianjin 300170 China

The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history. In this paper, the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at xikou, Zhen’an County, Shaanxi Province, is analyzed quantitatively, and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed. As a whole, the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in xikou, Zhen’an County, from the Late Carboniferous to the Early Permian. There is a significant increase in species diversity around the Carboniferous-Permian boundary, which is one of the biggest bio-events of the fusulinacean fauna, and represents the radiation of Pseudoschwagerininae subfamily in the studied area. Integrated fusulinacean species diversity into sequence stratigraphic framework, de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location, and is essentially controlled by the sea-level changes, especially by the high-frequency sea-level changes. Generally, the species diversity of fusulinaceans is low, and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level; whereas the species diversity of fusulinaceans is high, and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level. Within the third-order depositional sequence, the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low, and it increases upward. The fusulinacean species diversity is low within the transgressive syst

关键词： fusulinaceans, species diversity, high-frequency cyclothem, sequence stratigraphy, sea-level changes, Carboniferous-Permian boundary, Zhen'an, Shaanxi.

Influence of the impounding process of the Three Gorges Reservoir up to water level 172.5m on water eutrophication in the xiangxi Bay

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Science china(Technological sciences) 2010年第4期53卷 1114-1125页

作者： YANG ZhengJian1,LIU DeFu1,JI DaoBin1,2.& xiAO ShangBin1,3 1 College of Civil & Hydroelectric Engineering,china Three Gorges University,Yichang 443002.china 2.School of Water Resources & Hydropower Engineering,Wuhan University,Wuhan 430072.china 3 institute of earth environment,chinese Academy of sciences,xi’an 710075,china 1. College of Civil & Hydroelectric Engineering China Three Gorges University Yichang 443002 China2. School of Water Resources & Hydropower Engineering Wuhan University Wuhan 430072 China3. Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China

The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,*** hydrodynamic parameters and water quality parameters(*** velocity,temperature,turbidity and nutrient content) had been continuously monitored to reveal the influence of the impounding process of the TGR on the water eutrophication in the xiangxi Bay(XXB).The maximal daily rise of the water level of the TGR was about 2.38 *** water exchange between the mainstream(the Changjiang River) and the XXB of the TGR was enhanced by density current,and its main characteristics were a density-stratified flow in different *** water exchange reduced the differences of the water quality parameters(for example,temperature,turbidity,nutrient level,pH,etc.) between the mainstream and the XXB during the impounding ***,the water stability index in the mainstream remained small but it was lowered in the *** main causes included the dilution by water of lower concentration of the chlorophyll a(Chl.a) entering from the mainstream,the decline of the water stability,and the increase of suspended silt,which induced the Chl.a to decrease in the XXB during the impounding *** grade of the water eutrophication changed from middle eutrophic level to mesotrophic state in the ***,as available nutrients were imported into the XXB from the mainstream during the impounding process the risk of water eutrophication increases in the XXB in the future.

关键词： impounding density current eutrophication the xiangxi Bay the Three Gorges Reservoir

Discovery of eclogite and its geological significance in Qiangtang area, central Tibet

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Science Bulletin 2006年第9期51卷 1095-1100页

作者： LI Cai1, ZHAI Qingguo2. DONG Yongsheng1 & HUANG xiaopeng11. College of earth sciences, Jilin University, Changchun 130061,{2. 2. institute of Geology, chinese Academy of Geological sciences, Bei- jing 100037,{2. College of earth sciences Jilin University Changchun 130061 China institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China

Eclogite is first discovered from Qiang- tang area, central Tibet, which occurs as a lens in the high-pressure metamorphic belt comprising glauco- phane-muscovite schist and garnet-muscovite schist, along the south margin of Lungmu Co-Shuanghu Paleo-Tethys suture. A glaucophane 40Ar/39Ar age of 2.0 Ma and a phengite 40Ar/39Ar age of 2.1.9 Ma have been obtained from blueschists associated with eclogite. The rock consists of garnet, omphacite, amphibole, phengite, and rutile, etc, and the jadeite content in omphacite ranges from 32.7% to 38.95%. It is estimated that the temperature of the eclogite is 2.35 GPa. The discovery of Qiangtang ecologite fur- ther supports that there is a suture zone of Indo- chinese epoch in central Qiangtang area, and is very important for discssing the evolution of the pa- leo-ocean and paleo-plate tectonics in this area.

关键词： Qianghai-Tibet Plateau Qiangtang eclogite tectonics.

Spectral analysis of quasi-stationary sea surface topography from GRACE mission

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Science china earth {2. 2005年第11期48卷 2040-2048页

作者： ZHANG Zizhan1,2.& LU Yang1,3 1. institute of Geodesy and Geophysics, chinese Academy of {2., Wuhan 430077, china 2. Graduate School of the chinese Academy of {2., Beijing 100039, china 3. Unite Center for Astro-geodymics Research, chinese Academy of {2., Shanghai 2.0030, china 1. institute of Geodesy and Geophysics Chinese Academy of Sciences 430077 Wuhan China 2. Graduate School of the chinese Academy of sciences 100039 Beijing China 3. Unite Center for Astro-geodymics Research Chinese Academy of Sciences 200030 Shanghai China

During the last two decades satellite altimetry has offered an abundance of meas-urements of the sea surface resulting in the improvement of global mean sea surface height (MSSH) and marine geoid determination. On the other hand, with the launching of new genera-tion gravity satellites, some high accuracy long-wavelength gravity models are available. These breakthroughs give us a great opportunity for new estimation of quasi-stationary sea surface topography (QSST). In this paper, the new gravity model GGM01C derived from GRACE mission is briefly presented, and a new global high precision and high-resolution QSST is determined based on the GGM01C model and the global MSSH. The spectral features of the QSST esti-mated by GGM01C and EGM96 gravity model to degree/order 2.0 are discussed by spectral analysis. As a result, the QSST is mainly composed of long waves, medium waves partially and short waves scarcely, its power spectral structures are different between the zonal direction and the meridional direction, there are great differences between the two models, which maybe ex-plain why the ocean currents derived from the two gravity models by Tapley show different pat-terns.

关键词： quasi-stationary sea surface topography, mean sea surface height, GGM01, fast Fourier transform, spectral analysis

Estimation of annual actual evapotranspiration from nonsaturated land surfaces with conventional meteorological data

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Science china earth {2. 2004年第3期47卷 239-246页

作者： QIU xinfa1, ZENG Yan2. MIAO Qilong1 & YU Qiang2.1. Department of Geography, Nanjing institute of Meteorology, Nanjing 2.0044, china 2. institute of Geographic sciences and Natural Resources Research, chinese Academy of sciences, Beijing 100101, china Nanjing Inst Meteorol Dept Geog Nanjing 210044 Peoples R China chinese Acad Sci Inst Geog Sci Beijing 100101 Peoples R China chinese Acad Sci Nat Resources Res Beijing 100101 Peoples R China

Views diverge greatly on the relationship between actual evapotranspiration (AE) and potential evapotranspiration (PE). Penman showed that AE is determined in intensity by PE and changes proportionally as a function of PE. In contrast, Bouchet indicated that AE deter-mines PE and varies inversely with PE. Based on nearly 30 years data from 432.weather stations and 512.hydrological stations in china, the two different theories, Penman抯 assumption and Bouchet抯 complementary relationship between AE and PE, were tested on nine river basins. With data integration technique, the complementary relationship between AE and PE was dis-played entirely. A general model to estimate the actual evapotranspiration from nonsaturated surfaces by routine meteorological observations has been established on the basis of thorough analysis of the concept of PE. The results show that the calculations are all in error control of <10%, except for a few years over the Yellow River Basin.

关键词： complementary relationship of evapotranspiration, potential evapotranspiration, actual evapotranspiration.

Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

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chinese Science Bulletin 2009年第2期54卷 272-279页

作者： LIU WeiGuo1,2.& WANG Zheng1,3 1 State Key Laboratory of Loess and Quaternary Geology, institute of earth {2., chinese Academy of sciences, xi’an 710075, china 2.xi’an Jiaotong University, School of Human Settlement and Civil Engineering, xi’an 710049, china 3 Graduate University of chinese Academy of sciences, Beijing 100049, china chinese Acad Sci Inst Earth Environm State Key Lab Loess and Quaternary Geol Xian 710075 Peoples R China.

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern china, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern china under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2. to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3‰ to 7.2. with average of 4.1‰; and (2. mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for {2.al changes.

关键词：氮同位素物理性质化学性质环境论

Representation of microscale ocean wavenumber spectrum correct to the second order

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Science china earth {2. 2005年第4期48卷 549-554页

作者： YUAN Yeli2.& HUA Feng1,2.3 1. institute of Oceanology, chinese Academy of {2., Qingdao 2.6071, china 2. Key Laboratory of Marine Science and Numerical Modeling, State Oceanic Administration, Qingdao 2.6061, china 3. Graduate School of the chinese Academy of {2., Beijing 100039, china 1. Key Laboratory of Marine Science and Numerical Modeling State Oceanic Administration 266061 Qingdao China 2. institute of Oceanology Chinese Academy of Sciences 266071 Qingdao China 3. Graduate School of the chinese Academy of sciences 100039 Beijing China

In this paper, the analytical representations of four wave source functions in high-frequency spectrum range are given on the basis of ocean wave theory and dimensional analysis, and the perturbation method is used to solve the governing equations of ocean wave high-frequency spectrum on the basis of the temporally stationary and locally homogeneous scale relations of microscale wave. The microscale ocean wavenumber spectrum correct to the second order has an explicit structure, its first order part represents the equilibrium between dif- ferent source functions, and its second order part represents the contribution of microscale wave propagation.

关键词： temporally stationary and locally homogeneous, source function in high-frequency spectrum range, microscale ocean wavenumber spectrum.

Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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Science china earth {2. 2006年第5期49卷 554-560页

作者： FAN Ke1,2.3 & WANG Huijun2.1. Nansen-Zhu International Research Center, institute of Atmospheric Physics, chinese Academy of {2., Beijing 10002., china 2. Department of Atmospheric Science, Yunnan University, Kunming 650091, china 3. Graduate University of the chinese Academy of {2., Beijing 100049, china 1. Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Department of Atmospheric Science Yunnan University Kunming 650091 China 3. Graduate University of the chinese Academy of sciences Beijing 100049 China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.