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change of surface cover greenness in china between 2000 and 2010

Chinese science Bulletin 2012年第22期57卷 2835-2845页

作者： LIU Shuang1,4& GONG Peng1,2,31State Key Laboratory of Remote Sensing science, Jointly Sponsored by institute of Remote Sensing Applications of Chinese Academy of sciences,and beijing Normal university, beijing 100101, china 2institute for global change studies & center for earth system science, tsinghua university, beijing 100084, china 3Department of Environmental science, Policy and Management, university of California, Berkeley, CA94720, USA 4Graduate university of Chinese Academy of sciences, beijing 100049, china State Key Laboratory of Remote Sensing science Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate university of Chinese Academy of sciences Beijing China institute for global change studies & center for earth system science Tsinghua University Beijing China Department of Environmental science Policy and Management University of California Berkeley USA

Surface greenness reflects the situation of vegetation *** index calculated from the Red and Near Infrared bands of remote sensing images,whose values indicate the level of photosynthetic activity,is monotonically related to surface greenness when vegetation canopy does not fully cover the background *** for desert regions,vegetation index is positively correlated with vegetation ***,vegetation index can be used to study the change in greenness of desert *** study collected MODIS Normalized Difference Vegetation Index (NDVI) data from 2000 to 2010 and analyzed their change over china in this *** results showed that an increasing trend of NDVI occurred over 66.84% (OLS fitting) or 64.27% (LAD fitting) of china,indicating that china's greenness is increasing ***,desertification of china *** showing large increase in greenness are found in Shaanxi,Shanxi,Ningxia,Henan,Shandong,Qinghai,and Gansu while regions with large decrease in greenness are found in Northeast Inner Mongolia,South Tibet,Jiangsu,and *** of Qinghai,Gansu,Xinjiang and South Tibet could probably be driven by climate *** of greenness in Northeast Inner Mongolia was related to agricultural *** of greenness in Jiangsu and Shanghai was related to rapid *** factors did not exhibit obvious correspondence to the large increase in greenness in Shaanxi,Shanxi,Ningxia and Gansu,indicating that the changes might have been caused by human *** reduction of desert areas in china could probably have been caused by human management and protection at the national scale.

关键词：中国地表覆盖归一化植被指数植被覆盖度沙漠地区 NDVI 西藏南部气候因素

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Simulation of freezing and melting of soil on the northeast Tibetan Plateau

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Chinese science Bulletin 2011年第20期56卷 2145-2155页

作者： XIA Kun 1,2,3,LUO Yong 2,4,5 & LI WeiPing 2 1 institute of Atmospheric Physics,Chinese Academy of sciences,beijing 100029,china 2National Climate center,china Meteorological Administration,beijing 100081,china 3Graduate university of Chinese Academy of sciences,beijing 100049,china 4 center for earth system science,tsinghua university,beijing 100084,china 5Key Laboratory of earth system Numerical Simulation,Ministry of Education,beijing 100084,china institute of Atmospheric Physics Chinese Academy of Sciences National Climate center China Meteorological Administration Graduate university of Chinese Academy of sciences center for earth system science Tsinghua University Key Laboratory of earth

Using observational data spanning the period from February to December 2009 and recorded at the Suli station in Qinghai Province,the land-surface model CLM3.0 was employed to simulate the freezing and melting of *** results indicate that the simulated soil temperature is higher than the observed soil temperature and the ultimate thawing date is earlier than the observed date during the melting *** the freezing period,the simulated soil temperature is lower than the observed soil temperature and the ultimate freezing of the deep soil is earlier than that ***,the simulation of freezing is better than that of melting,and the simulation of a shallow layer is better than that of a deeper *** the original CLM3.0,it is assumed that frozen soil begins to melt when the soil temperature exceeds 0C,which is inconsistent with *** critical freeze-thaw temperature was calculated according to thermodynamics equations and the freeze-thaw condition was *** this work,the melting rate for frozen soil was reduced using the modified scheme,and the simulated soil temperature was lowered. Meanwhile,the refreezing of soil during the melting season was well simulated and more closely matched ***,it was found that the rates of melting and freezing differ,with the former being slower than the latter,but refreezing during the melting season is rather quick.

关键词：土壤温度冻结期青藏高原东北部模拟融化观测数据热力学方程表面模型

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Estimating forest aboveground biomass using HJ-1 Satellite CCD and ICESat GLAS waveform data

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science china earth sciences 2010年第S1期53卷 16-25页

作者： GUO ZhiFeng1,CHI Hong1,2 & SUN GuoQing1,3 1State Key Laboratory of Remote Sensing science,Jointly Sponsored by the institute of Remote Sensing Applications of Chinese Academy of sciences and beijing Normal university,institute of Remote Sensing Applications,Chinese Academy of sciences,beijing 100101,china 2Graduate university of Chinese Academy of sciences,beijing 100049,china 3Department of Geography university of Maryland,College Park,MD 20742,USA 1. State Key Laboratory of Remote Sensing science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing 100101 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Department of Geography University of Maryland College Park MD 20742 USA

The ecosystem in northeastern china and the Russian Far East is a hotspot of scientific research into the global carbon *** aboveground biomass(AGB) is an important component in the land surface carbon *** this study,using forest inventory data and forest distribution data,the AGB was estimated for forest in Daxinganlin in northeastern china by combining charge-coupled device(CCD) data from the Small Satellite for Disaster and Environment Monitoring and Forecast(HJ-1) and Geoscience Laser Altimeter system(GLAS) waveform data from the Ice,Cloud and land Elevation Satellite(ICESat).The forest AGB prediction models were separately developed for different forest types in the research area at GLAS footprint level from GLAS waveform parameters and field survey plot biomass in the Changqing(CQ) Forest center,which was calculated from forest inventory *** resulted statistical regression models have a R2=0.68 for conifer and R2=0.71 for broadleaf *** models were used to estimate biomass for all GLAS footprints of forest located in the study *** GLAS footprint biomass coupled with various spectral reflectivity parameters and vegetation indices derived from HJ-1 satellite CCD data were used in multiple regression analyses to establish biomass prediction models(R2=0.55 and R2=0.52 for needle and broadleaf respectively).Then the models were used to produce a forest AGB map for the whole study area using the HJ-1 *** data obtained from forest inventory data of the Zhuanglin(ZL) Forest center were used as independent field measurements to validate the AGB estimated from HJ-1 CCD data(R2=0.71).About 80% of biomass samples had an error less than 20 t ha-1,and the mean error of all validation samples is 5.74 t *** pixel-level biomass map was then stratified into different biomass levels to illustrate the AGB spatial distribution pattern in this *** was found that HJ-1 wide-swath data and GLAS waveform data can be combined to estim

关键词： Disaster and Environment Monitoring and Forecast Satellite ICESat GLAS waveform boreal forest forest aboveground biomass multiple linear regression

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Maximum Wind Speeds changes over china

Maximum Wind Speeds Changes over China

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第28届中国气象学会年会

作者： JIANG Ying1,LUO Yong2,3,ZHAO Zongci2,3 1 Public Weather Service center of CMA,beijing 100081,china 2 center for earth system science of tsinghua university,beijing,100084,china 3 National Climate center of china,beijing,100081

An intensive analysis is undertaken for the characteristics of maximum wind speed（WSMax） change for 1956-2004 across china based on the observed station data,with further study of the changes of WSMax for 2046-2065 and 2080-2099 as projected by three global climate models（GFDLM2,CCCMAGCM3 and MRIGCM2） and their ensembles which proposed in the IPCC Fourth Assessment Report（AR4） . It is found that the observed annual and seasonal WSMax and the number of gale days show obviously the declining trends. The annual WSMax and the gale days reduced by about-1.46 m/s per decade and-3.0 days per decade during the study period 1956-2004,respectively. The amplitudes of annual and seasonal WSMax decreases were bigger than that of annual and seasonal average wind speeds（WSAvg） . Under the weakening of both East Asian winter and summer monsoons,the distinct decreases of WSMax associated with the weakening of cold wave in china and the decreasing number（weakening intensity） of landing typhoons in the northwestern Pacific Ocean. The global climate models GFDLM2,MRIGCM2 and EBGCM（the ensemble of GFDLM2,MRIGCM2 and CCCMAGCM3） areto project consistently that the annual and seasonal WSMax reduce during 2046-2065 and 2080-2099 to compare with 1981-2000,i.e. the WSMax for 2046-2065 decreases by-3.0m/s relative to 1981-2000. It is also noticed that the WSMax decreases during 2046-2065 and 2080-2099 have a good relationship with both the cold wave weakening as corresponding to the winter monsoon weakening and the decreasing numbers of tropical cyclones over the northwestern Pacific Ocean in the summer of the 21st century.

关键词： maximum wind speed,change,projection,china

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global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback

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science china(Technological sciences) 2010年第3期53卷 595-607页

作者： ZHANG Li1,WANG HuaiLei1 & HU HaiYan1,2 1 MOE Key Lab of Mechanics and Control of Aerospace Structures,Nanjing university of Aeronautics and Astronautics,Nanjing 210016,china 2 School of Aerospace Engineering,beijing institute of Technology,beijing 100081,china 1. MOE Key Lab of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China

This paper presents both analytical and numerical studies on the global view of Hopf bifurcations of a van der Pol oscillator with delayed state *** on a detailed analysis of the stability switches of the trivial equilibrium of the system,the stability charts are given in a parameter space consisting of the time delay and the feedback *** center manifold reduc-tion and the normal form method are used to study Hopf bifurcations with respect to the time *** gain an insight into the persistence of a Hopf bifurcation as the time delay varies farther away from its critical value,the method of multiple scales is used to obtain the global view of Hopf bifurcations with respect to the time *** the analytical results of Hopf bifurca-tions and global view of those bifurcations are validated via a collocation scheme implemented on *** most important discovery in this paper is the well-structured global view of Hopf bifurcations for the system of concern,showing the generality of the persistence of Hopf bifurcations.

关键词： Hopf bifurcation global view center manifold reduction method of multiple scales collocation scheme

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Orbit determination and prediction accuracy analysis for a regional tracking network

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science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1130-1138页

作者： ZHOU ShanShi 1,2,3 ,HU XiaoGong 1 & WU Bin 1 1 Shanghai Astronomical Observatory,Chinese Academy of sciences,Shanghai 200030,china 2 Graduate university of Chinese Academy of sciences,beijing 100049,china 3 Research center of GNSS,Wuhan 430079,china 1. Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Research Center of GNSS Wuhan 430079 China

china's COMPASS satellite navigation system relies on a regional tracking network to provide navigation services. Limited by its geographic border,the regional network is able to cover only 30% of the medium-earth-orbits(MEO). Accuracy of determined and predicted orbits is not able to satisfy system requirements if the tracking data processing strategy for global tracking network processing is used for the regional network. Two major error sources for orbital prediction are accuracy of initial orbital elements and dynamical modeling. To achieve better prediction accuracy,we propose a two-step orbit determination and prediction strategy. For step 1,only solar radiation pressure(SRP) parameters are estimated along with the orbital elements and other parameters; for step 2,all parameters are estimated but the SRP parameters are tightly constrained to their step 1 estimates. Experimenting with data from a regional GPS network,we conclude for orbital prediction using the proposed two-step strategy,the average user range error(URE) for 24-h prediction arcs is better than 0.6 m.

关键词： orbit determination and prediction regional tracking network URE

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Plant Diversity Reduces the Effect of Multiple Heavy Metal Pollution on Soil Enzyme Activities and Microbial Community Structure

Plant Diversity Reduces the Effect of Multiple Heavy Metal P...

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第六届全国环境化学大会暨环境科学仪器与分析仪器展览会

作者： Yang Gao~(1,4),Jun Xia~1,Yafeng Wang~2,Chiyuan Miao~3,Pei Zhou~4 (1.Key Laboratory of Water Cycle and Related Land Surface Processes,institute of Geographic sciences and Natural Resources Research,Chinese Academy of sciences,beijing 100101,china 2.State Key Laboratory of Urban and Regional Ecology,Research center for Eco-Environmental sciences,Chinese Academy of sciences,beijing 100085,china 3.College of global change and earth system science,beijing Normal university,beijing 100078,china 4.School of Agriculture and Biology,Shanghai Jiaotong university,Shanghai 200240,china)

＜正＞It is unclear whether certain plant species and plant diversity could offset the impacts of multiple heavy metal pollution on soil microbial structure and soil enzyme *** amplified polymorphic DNA（RAPD） was used to analyze the genetic diversity and microbial similarity in planted and unplanted soil under combined cadmium （Cd） and lead（Pb） pollution.A metal hyperaccumulator,Brassica juncea,and a common plant,Festuca arundinacea Schreb,were used in this *** results showed that micro-organism quantity in planted soil significantly increased,compared with that in

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Dynamical diagnosis of the breakup of the stratospheric polar vortex in the Northern Hemisphere

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science china earth sciences 2007年第9期50卷 1369-1379页

作者： WEI Ke1,2, CHEN Wen1 & HUANG RongHui1 1 center for Monsoon system Research, institute of Atmospheric Physics, Chinese Academy of sciences, beijing 100080, china 2 Graduate university of the Chinese Academy of sciences, beijing 100049, china center for Monsoon system Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100080 China Graduate university of the Chinese Academy of sciences Beijing 100049 China center for Monsoon system Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100080 China

The research on climate change in polar regions, especially on the role of polar in the global climate system, has gain unprecedented level of interest. It has been the key scientific issue of the International Polar Year program (IPY, 2007—2008). In this paper, we dealt with the debate upon the breakup time of the stratospheric polar vortex in boreal spring. An observational study of the relation between stratospheric polar vortex breakup and the extra-tropical circulation was performed. The mean breakup date—when the winter westerly at the core of polar jet turns to summer easterly—is about April 10. The breakup time has large interannual variation with a time span of about 2 months. It also has a long-term trend with the 1990s and 2000s witnessing more and more late breakups of polar vortex. Composite of wind speed at the core of polar jet for the extremely early and late breakup years shows that late years have two periods of westerly weakening while early breakup years have only one. The flrst weakening in the late years happens in middle January with wind speed dropping sharply from more than 40 m s^(-1) to about 15 m s^(-1). This is accompanied with anomalous activities of planetary waves in both stratosphere and troposphere; while the second weakening in the late breaking years is mainly the results of diabatic heating with very weak wave activities. In early breakup years, the transition from westerly to easterly is rapid with wind speed dropping from more than 30 m s^(-1) to less than -10 m s^(-1) within a month. This evolution is associated with a strong bidirectional dynamical coupling of the stratosphere and troposphere. The circulation anomalies at low troposphere are also analyzed in the extremely early and late breakup years. It shows that there are significant differences between the two kinds of extreme years in the geopotential height and temperature composite analysis, indicating the dynamical coupling of stratosphere and troposphere with the evo

关键词： stratospheric polar vortex, wave-flow interaction, diabatic heating, final breakup, stratosphere-troposphere coupling

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Relationship and its instability of ENSO--Chinese variations in droughts and wet spells

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science china earth sciences 2007年第1期50卷 145-152页

作者： SU MingFeng1,2 & WANG HuiJun1 1 Nansen-Zhu International Research center, institute of Atmospheric Physics, Chinese Academy of sciences, beijing 100029, china 2 Graduate university of Chinese Academy of sciences, beijing 100039, china 1. Nansen-Zhu International Research center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Graduate university of Chinese Academy of sciences Beijing 100039 China

Monthly data of Self-Calibrated Palmer Drought Severity Index (PDSI) from 1951 to 2000 are calculated using historical precipitation and temperature data for Chinese 160 stations. Temporal and spatial pat-terns of the first empirical orthogonal function (EOF) of the PDSI reveals a fairly linear trend resulting from trends in precipitation and surface temperature, which is similar to the linear PDSI trend during 1951―2000 calculated using all monthly data. The EOF analysis also reveals that the leading mode correlates significantly with ENSO events in time and space. The ENSO EOF shows that during the typical warm phase of ENSO, surface conditions are drier in most regions of china, especially North china, but wetter than normal in the southern regions of Changjiang River, and Northwest china. During the typical cold phase of ENSO, these anomalies reverse sign. From 1951 to 2000, there are large multi-year to decadal variations in droughts and wet spells over china, which are all closely related to strong El Nio events. In other words, when one strong El Nio event happens, there is a possible big variability in droughts and wet spells over china on the multi-year or decadal scale. studies also sug-gest that during the last 2―3 decades climate changes over china, especially North china's drying and northwest china's wetting, are closely related to the shift in ENSO towards warmer events and global warming since the late 1970s. The instability of the relationship is also studied. It is revealed that there is a good correlation between ENSO and Chinese variations in droughts and wet spells in the 3―8-year band, but the correlation between ENSO and Chinese variations in droughts and wet spells is instable. studies suggest that there are decadal changes in the correlation: the wavelet coherency between ENSO and Chinese variations in droughts and wet spells is high during 1951―1962 and 1976―1991, but low during 1963―1975 and 1992―2000.

关键词： PDSI variations droughts and wet Spells ENSO instability.

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Distribution characteristics and petroleum geological significance of the Silurian asphaltic sandstones in Tarim Basin

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science china earth sciences 2004年第Z2期47卷 199-208页

作者： ZHANG Jun1,2, PANG Xiongqi1,2, LIU Luofu1,2, JIANG Zhenxue1,2 & LIU Yunhong3 1. Basin and Reservoir Research center, university of Petroleum, beijing 102249, china 2. Key Laboratory for Hydrocarbon Accumulation Mechanism of the Ministry of Education, university of Petroleum, beijing 102249, china 3. Korla Research institute of Geophysics, Bureau of Geophysics Prospecting, Korla 841000, china Basin and Reservoir Research center University of Petroleum Beijing 102249 China Key Laboratory for Hydrocarbon Accumulation Mechanism of the Ministry of Education University of Petroleum Beijing 102249 China Korla Research institute of Geophysics Bureau of Geophysics Prospecting Korla 841000 China

The Tarim Basin is a typical superimposed basin in which there have occurred mul-tiphase adjustment and destruction of the reservoirs. The widely distributed asphaltic sandstones of the Silurian are the very product after destruction of the reservoirs. studies show that the Silu-rian asphaltic sandstones distributed in both the middle and western parts on the basin are con-trolled chiefly by the Caledonian oil source area and by the Tazhong, Tabei and Bachu uplifts, whereas the distribution of the asphaltic sandstones on local structural belts is controlled by the reservoirs sedimentary system. Vertically, most of the asphaltic sandstones are under the re-gional caprock of red mudstones and the upper sandstone section of compact lithology. Due to the difference of hydrocarbon destruction in the early stage and the influence of hydrocarbon recharge in the late stage, the asphaltic sandstones and oil-bearing sandstones in the Tazhong area can be vertically divided into the upper and lower sections and they have an interactive distribution relationship as well. Asphaltic sandstones exist not only in intergranular pores but also inside the grains of sand and between the crevices, proving the destruction of early reser-voirs due to uplifting. The existence of asphaltic sandstones over a large area reveals that the large-scale migration and accumulation and the subsequent destruction of hydrocarbons in the Craton area. The destruction caused a loss of the reserve resources of the Palaeozoic amount-ing to nearly 13.3 billion tons. Asphaltic sandstones formed after the destruction of oil and gas may serve as an effective caprock which is beneficial to accumulation of hydrocarbons and for-mation of the pool sealed by asphaltic sandstones in the later stage. The destruction of the early Silurian hydrocarbons depends on the stratigraphic burial depth. The deep part under the north-ern slope of Tazhong is an area favorable to search of undestroyed Silurian oil reservoirs.

关键词： Tarim Basin, asphaltic sandstone, Silurian, hydrocarbon destruction, distribution characteristics, reserve of resources.

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