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| 1 | Energy balance closure at ChinaFLUX sites显示文摘Network of eddy covariance observation is measuring long-term carbon and water fluxes in contrasting ecosystems and climates. As one important reference of independently evaluating scalar flux estimates from eddy covariance, energy balance closure is used widely in study of carbon and water fluxes. Energy balance closure in ChinaFLUX was evaluated by statistical regression of turbulent energy fluxes (sensible and latent heat) against available energy (net radiation, soil heat flux, canopy heat storage) and the energy balance ratio (EBR) and the frequency distribution of relative errors of energy balance (δ). The trends of diurnal and seasonal variation of energy balance in ChinaFLUX were analyzed. The results indicated that the imbalance was prevalent in all observation sites, but there were little differences among sites because of the properties variation of sites. The imbalance was greater during nocturnal periods than daytime and closure was improved with friction velocity intensifying. Generally the results suggested that estimates of the scalar turbulent fluxes of sensible and latent heat were underestimated and/or that available energy was overestimated. Finally, we discussed certain factors that are contributed to the imbalance of energy, such as systematic errors associated with the sampling mismatch, systematic instrument bias, neglected energy sinks, low and high frequency loss of turbulent fluxes and advection of heat and water vapor. | LI Zhengquan, YU Guirui, WEN Xuefa, ZHANG Leiming, REN Chuanyou & FU Yuling Chinese Ecosystem Research Network Synthesis Research Center, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Graduate School of the Chinese Academy of Sciences, Beijing 100039, China | 2005 | Science China Earth Sciences2005，48，z1： | 50 |
| 2 | Efficient signcryption between TPKC and IDPKC and its multi-receiver construction显示文摘The primitive signcryption provides authenticity and privacy simultaneously. In this paper, we present efficient signcryption schemes between the traditional public key cryptosystem (TPKC) and the identity based cryptosystem (IDPKC). In contrast, all the existing signcryption schemes available in the literature, to our knowledge, are limited to within one type of cryptosystem. We also discuss them in the multi-receiver setting. Formal security proofs are provided to guarantee the security for our schemes, in the random oracle model, under the hardness of the bilinear Diffie-Hellman problem. | SUN YinXia & LI Hui Key Laboratory of Computer Networks and Information Security, Ministry of Education, Xidian University, Xi’an 710071, China | 2010 | Science China(Information Sciences)2010，53，3： | 29 |
| 3 | Quantum secure direct communication with cluster states显示文摘A quantum secure direct communication protocol with cluster states is proposed.Compared with the deterministic secure quantum communication protocol with the cluster state proposed by Yuan and Song(Int.J.Quant.Inform.,2009,7:689),this protocol can achieve higher intrinsic efficiency by using two-step transmission.The implementation of this protocol is also discussed. | CAO WeiFeng 1,YANG YuGuang 3,4,5* & WEN QiaoYan 2 1 College of Electric and Information Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China 2 State Key Laboratory of Networking and Switching Technology,Beijing University of Posts and Telecommunications,Beijing 100876,China 3 College of Computer Science and Technology,Beijing University of Technology,Beijing 100124,China 4 State Key Laboratory of Integrated Services Network,Xidian University,Xi’an 710071,China 5 State key Laboratory of Information Security Gradute University of Chinese Academy of Sciences,Beijing 100049,China | 2010 | Science China(Physics,Mechanics & Astronomy)2010，53，7： | 20 |
| 4 | Changes in individual plant traits and biomass allocation in alpine meadow with elevation variation on the Qinghai-Tibetan Plateau显示文摘Plant traits and individual plant biomass allocation of 57 perennial herbaceous species,belonging to three common functional groups (forbs,grasses and sedges) at subalpine (3700 m ASL),alpine (4300 m ASL) and subnival (≥5000 m ASL) sites were examined to test the hypothesis that at high altitudes,plants reduce the proportion of aboveground parts and allocate more biomass to belowground parts,especially storage organs,as altitude increases,so as to geminate and resist environmental stress.However,results indicate that some divergence in biomass allocation exists among organs.With increasing altitude,the mean fractions of total biomass allocated to aboveground parts decreased.The mean fractions of total biomass allocation to storage organs at the subalpine site (7%±2% S.E.) were distinct from those at the alpine (23%±6%) and subnival (21%±6%) sites,while the proportions of green leaves at all altitudes remained almost constant.At 4300 m and 5000 m,the mean fractions of flower stems decreased by 45% and 41%,respectively,while fine roots increased by 86% and 102%,respectively.Specific leaf areas and leaf areas of forbs and grasses deceased with rising elevation,while sedges showed opposite trends.For all three functional groups,leaf area ratio and leaf area root mass ratio decreased,while fine root biomass increased at higher altitudes.Biomass allocation patterns of alpine plants were characterized by a reduction in aboveground reproductive organs and enlargement of fine roots,while the proportion of leaves remained stable.It was beneficial for high altitude plants to compensate carbon gain and nutrient uptake under low temperature and limited nutrients by stabilizing biomass investment to photosynthetic structures and increasing the absorption surface area of fine roots.In contrast to forbs and grasses that had high mycorrhizal infection,sedges had higher single leaf area and more root fraction,especially fine roots. | MA WeiLing1,2,SHI PeiLi1*,LI WenHua1,HE YongTao1,ZHANG XianZhou1,SHEN ZhenXi1 & CHAI SiYue1,2 1Lhasa National Ecological Research Station,Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China 2Graduate University of Chinese Academy of Sciences,Beijing 100049,China | 2010 | Science China(Life Sciences)2010，53，9： | 19 |
| 5 | Advances in carbon flux observation and research in Asia显示文摘As an important component of FLUXNET, Asia is increasingly becoming the hotspot in global carbon research for its vast territory, complex climate type and vegetation diversity. The present three regional flux observation networks in Asia (i.e. AsiaFlux, KoFlux and ChinaFLUX)have 54 flux observation sites altogether, covering tropic rainforest, evergreen broad-leaved forest, broad-leaved and coniferous mixed forest, shrubland, grassland, alpine meadow and cropland ecosystems with a latitudinal distribution from 2°N to 63°N. Long-term and continuous fluxes of carbon dioxide, water vapor and energy between the biosphere and atmosphere are mainly measured with eddy covariance technique to (1) quantify and compare the carbon, water and energy budgets across diverse ecosystems; (2) quantify the environmental and biotic controlling mechanism on ecosystem carbon, water and energy fluxes; (3) validate the soil-vegetation-atmosphere model; and (4) serve the integrated study of terrestrial ecosystem carbon and water cycle. Over the last decades, great advancements have been made in the theory and technology of flux measurement, ecosystem flux patterns, simulation and scale conversion by Asian flux community. The establishment of ChinaFLUX has greatly filled the gap of flux observation and research in Eurasia. To further promote the flux measurement and research,accelerate data sharing and improve the data quality, it is necessary to present a methodological system of flux estimation and evaluation over complex terrain and to develop the integrated research that combines the flux measurement, stable isotope measurement, remote sensing observation and GIS technique. It also requires the establishment of the Joint Committee of Asian Flux Network in the Asia-Pacific region in order to promote the cooperation and communication of ideas and data by supporting project scientists, workshops and visiting scientists. | YU Guirui, ZHANG Leiming, SUN Xiaomin, FU Yuling & LI Zhengquan Synthesis Center of Chinese Ecosystem Research Network (CERN), Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Graduate School of the Chinese Academy of Sciences, Beijing 100039, China | 2005 | Science China Earth Sciences2005，48，z1： | 16 |
| 6 | RPPK modulation with high data rates显示文摘With the development of communication technology, the precious frequency spectrum is becoming more and more crowded. Exploiting the particular filter with zero group delay, ultra narrow band (UNB) modulation is intended for acquiring the high frequency efficiency. Unfortunately, this UNB filter is confronted with great challenges from the classical communication theories. The validation on its realization is also difficult. This paper proposes a novel UNB modulation, namely random pulse position keying (RPPK). It is demonstrated from analysis that there is no inessential discrete spectral line in modulated signal’s power density spectrum (PDS), and the UNB filter has been successfully avoided. Consequently, RPPK is rather explicit in theory and simple in implementation. As is shown by the simulation, the frequency utilization of RPPK can even reach 100 bits/s/Hz. Its optimum receiving performance is slightly inferior to BPSK, yet is much superior to that of other UNB modulations such as VMSK/2. Moreover, multi-access and confidentiality are additional benefits to UNB users. | LI Bin , ZHOU Zheng & ZOU WeiXia Key Laboratory of Universal Wireless Communications, Ministry of Education Wireless Network Laboratory, Beijing University of Posts and Telecommunications, Beijing 100876, China | 2010 | Science China(Information Sciences)2010，53，2： | 16 |
| 7 | Carbon isotope ratios of C_(4) plants in loess areas of North China显示文摘Carbon isotope ratios (δ 13C) of 89 C4 plant samples were determined from the loess area in North China. δ 13C values vary between –10.5‰ and –14.6‰ with a mean of –12.6‰. Along a pre-cipitation gradient from the semi-moist area to the semiarid area, then to the arid area, the δ 13C val-ues of C4 plants show a slight decreasing trend. The δ 13C values of C4 plants in the dry season are found lower than those in the wet season. These trends are opposite to those observed for C3 spe-cies. | WANG Guoan1,2,3, HAN Jiamao 2, ZHOU Liping3, XIONG Xiaogang4, TAN Ming2, WU Zhenhai5 & PENG Jun6 1. Department of Plant Nutrition, China Agricultural University, Beijing 100094, China 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 3. College of Environmental Sciences, MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China 4. Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China 5. Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712100, China 6. Network Center, China Agricultural University, Beijing 100094, China | 2006 | Science China Earth Sciences2006，49，1： | 16 |
| 8 | Turbulence flux measurement above the overstory of a subtropical Pinus plantation over the hilly region in southeastern China显示文摘Continuous turbulence flux measurement using the eddy covariance (EC) technique was made from January 1 to December 31 in 2003 at two and three canopy heights of a subtropical Pinus plantation on the red earth hilly region in southeastern China. To be able to make sure that the measured turbulence flux will equal the net ecosystem/atmosphere exchange, the quality of the data has to be assessed. Three criteria were investigated here, including the power spectra and cospectra analyses, flux variance similarity (integral turbulence test) and energy balance closure. The spectral analyses suggested that above-canopy power spectral slopes for all velocity components and scalars such as CO2, H2O and air temperature followed the expected -2/3 power law in the inertial subrange, and their cospectral slopes were close to -4/3 power law in the inertial subrange. The important contribution of large-scale motions to energy and mass transfer above the canopy at higher measurement level was also confirmed by the spectral analyses. The eddy covariance systems have the ability to resolve fluctuations associated with small-scale eddies and did not induce an obvious underestimation of the measured turbulence flux. The Monin-Obukhov similarity functions for the normalized standard deviation of vertical wind speed and air temperature were well-defined functions of atmospheric stability at two heights above the forest canopy, which indicated that turbulence flux measurements made at two heights were within the surface layer. Nocturnal flux underestimation and departures of this normalized standard deviation of vertical wind speed similarity function from that expected from Monin-Obukhov theory were a function of friction velocity. Thus, an optimal criterion of friction velocity was determined to be greater than 0.2-0.3 m s-1 for nocturnal fluxes so that the eddy covariance flux measurement was under high turbulent mixing conditions. Energy balance closure reached about 72%-81% at the studied site, which was comparable to the 10%-30% of energy imbalance reported in the literature. However, the energy balance closure could be only used as a useful reference criterion. | WEN Xuefa, YU Guirui, SUN Xiaomin & LIU Yunfen Chinese Ecosystem Research Network Synthesis Research Center, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Graduate School of the Chinese Academy of Sciences, Beijing 100039, China | 2005 | Science China Earth Sciences2005，48，z1： | 14 |
| 9 | An efficient ranging method based on Chinese remainder theorem for RIPS measurement显示文摘The radio interferometric positioning system(RIPS) measures the phase difference of the interference signal to provide high accuracy and at the same time maintain simple hardware configuration for wireless sensor networks.However, it suffers from phase ambiguity problem because of the periodicity of phase, which makes it hard to determine the actual distance difference only from a single phase measurement.To solve the problem, RIPS makes multiple measurements at different frequencies so as to determine the distance difference from multiple phases.However, this is a computationally intensive searching process and not suitable for energyconstrained wireless sensor nodes.In this paper, we introduce the Chinese remainder theorem(CRT) to RIPS to solve the phase ambiguity problem.Meanwhile, we utilize some properties of the coefficients in the CRT algorithm to avoid the over-sensitivity of the traditional CRT, which increases the robustness of the algorithm.We apply this robust CRT algorithm to the ranging process which calculates the distance difference directly from a closed-form equation and therefore reduces the response time and the energy consumption of the ranging procedure. | WANG Chen , YIN QinYe & WANG WenJie Ministry of Education Key Lab for Intelligent Networks and Network Security, Xi’an Jiaotong University, Xi’an 710049, China | 2010 | Science China(Information Sciences)2010，53，6： | 13 |
| 10 | Seasonal patterns and environmental control of ecosystem respiration in subtropical and temperate forests in China显示文摘Continuous measurement of carbon dioxide exchange using the eddy covariance (EC) technique was made at two ChinaFLUX forest sites including the young subtropical Pinus plantation (Qianyanzhou) and old temperate broad-leaved Korean pine mixed forest (Changbai Mountains) as part of the ChinaFLUX network. Seasonal patterns and environmental control of ecosystem respiration in the subtropical and temperate forests were evaluated by the often-used multiplicative model and Q10 model as a function of temperature and soil water content. The resuits suggested that ( i ) temperature was found to be a dominant factor in the ecosystem respiration, and most of the temporal variability of ecosystem respiration was explained by temperature. However, in the drought-stressed ecosystem, soil water content controlled the temporal variability of ecosystem respiration other than temperature effects, and soil water content became a dominat factor when severe drought affected the ecosystem respiration; (ii) the regression models analysis revealed that in the drier soil, ecosystem respiration was more sensitive to soil moisture than was expressed by the often-used multiplicative model. It was possible to accurately estimate the seasonal variation of ecosystem respiration based on the Q10 model; and (iii)annual ecosystem respiration derived from the often-used multiplicative model was 1209 g C m-2and 1303 g C m-2, and was consistently a little higher than the Q10 model estimates of 1197 g C m-2 and 1268 g C m-2 for Qianyanzhou and Changbai Mountains, respectively. | YU Guirui, WEN Xuefa, LI Qingkang, ZHANG Leiming, REN Chuanyou, LIU Yunfen & GUAN Dexin Chinese Ecosystem Research Network Synthesis Research Center, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Graduate School of the Chinese Academy of Sciences, Beijing 100039, China | 2005 | Science China Earth Sciences2005，48，z1： | 13 |
| 11 | Nonlinear Dynamics and Stability of Neural Networks with Delay-Time显示文摘In this paper we study the dynamic properties and stabilities of neural networks with delay-time (which includes the time-varying case) by differential inequalities and Lyapunov function approaches. The criteria of connective stability, robust stability, Lyapunov stability, asymptotic atability, exponential stability and Lagrange stability of neural networks with delay-time are established, and the results obtained are very useful for the design, implementation and application of adaptive learning neural networks. | L. C. Jiao, member, IEEE, and Zheng Bao, Senior member, IEEECenter for Neural Networks and Institute of Elec. Eng, Xidian University, Xian 710071, China | 1992 | Journal of Systems Engineering and Electronics1992，3，2： | 11 |
| 12 | Mobile Ubiquitous Service Environment显示文摘The Mobile Ubiquitous Service Environment (MUSE),established through the coordination and integration of mobile telecommunications and ubiquitous network,in the pursuit of Always Best Experience (ABE),represents the major development trend for the next generation mobile wireless network. Research on MUSE will involve the integration of the computing model system,service platform system,operating system and terminal structure system,all of which involve exploration and innovation of a new networking structure,its control and management as well as way of measuring. The change in network resources triggers the change in network computing models. To let readers have a basic understanding of MUSE,this lecture introduces it in four sections. This section focuses on the development and demand analysis of the service platform. | Zhang Ping,Ji Yang,Feng Zhiyong (Research Center for Wireless New Technology,Beijing University of Posts and Telecommunications,Beijing 100876,China) The Mobile Ubiquitous Service Environment (MUSE),established through the coordination and integration of mobile telecommunications and ubiquitous network,in the pursuit of Always Best Experience (ABE),represents the major development trend for the next generation mobile wireless network. Research on MUSE will involve the integration of the computing model system,service platform system,operating system and terminal structure system,all of which involve exploration and innovation of a new networking structure,its control and management as well as way of measuring. The change in network resources triggers the change in network computing models. To let readers have a basic understanding of MUSE,this lecture introduces it in four sections. This section focuses on the development and demand analysis of the service platform. | 2007 | ZTE Communications2007，5，2： | 10 |
| 13 | Secure network coding in the presence of eavesdroppers显示文摘Our concern, in the paper, is to construct information-theoretic secure network coding in the presence of eavesdroppers. Based on the generalized attack model and all-or-nothing transformation, the security of network coding in the generalized combination network can be characterized by the network capacity and the min-cut bound of wiretapping set from the source. Furthermore, it can be extended to any directed acyclic networks with single source. Compared with the traditional results, we construct information-theoretic secure network coding without additional encryptions and giving up any capacity. | LUO MingXing1,2,3, YANG YiXian1,2,3, WANG LiCheng1,2,3 & NIU XinXin1,2,3 1Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876, China 2Key Laboratory of Network and Information Attack and Defence Technology of MOE, Beijing University of Posts and Telecommunications, Beijing 100876, China 3National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876, China | 2010 | Science China(Information Sciences)2010，53，3： | 8 |
| 14 | Threshold quantum secret sharing between multi-party and multi-party显示文摘A threshold quantum secret sharing (TQSS) scheme between multi-party and multi-party was proposed using a sequence of single photons,which is useful and efficient when the parties of communication are not all present. We described the process of this TQSS scheme and discussed its security. It was shown that entan-glement is not necessary for quantum secret sharing. Moreover,the theoretic effi-ciency was improved to approach 100% as almost all the instances can be used for generating the private key,and each photon can carry one bit of information. This protocol is feasible with the present-day technique. | YANG YuGuang1,2,3 & WEN QiaoYan4 1 College of Computer Science and Technology,Beijing University of Technology,Beijing 100124,China 2 State Key Laboratory of Integrated Services Network,Xidian University,Xi’an 710071,China 3 State Key Laboratory of Information Security (Graduate University of Chinese Academy of Sciences),Beijing 100049,China 4 State Key Laboratory of Networking and Switching Technology,Beijing University of Posts and Tele-communications,Beijing 100876,China | 2008 | Science China(Physics,Mechanics & Astronomy)2008，51，9： | 8 |
| 15 | 浅谈动力环境集中监控系统的应用与发展显示文摘通过纵览动力环境集中监控的发展历程,本文概要总结了动力环境集中监控系统数据采集、数据传输、基本组网的主要技术,重点分析了目前动力环境集中监控系统的应用水平和系统稳定性与告警过滤两方面性能的应用现状,探讨了动力环境集中监控系统在B接口、A接口、数据挖掘和科学规划方面的发展方向。 | Emerson Network Power Co. , Ltd. | 2007 | 电源世界2007，，1： | 8 |
| 16 | Construction of nonbinary quantum cyclic codes by using graph method显示文摘Using the graph method proposed by Schlingemann and Werner, this paper introduces a technique to construct nonbinary quantum cyclic codes and provides a specific example. We also construct the quantum codes [[8,2,4]]p and [[n, n - 2,2]]p for all odd primes p by the graph method. | LIU Tailin1,2,3, WEN Qiaoyan1 & LIU Zihui4 1. School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China 2. State Key Laboratory of Integrated Services Network, Xidian University, Xi’an 710071,China 3. Shandong Finance Institute, Jinan 250014, China 4. School of Mathematical Sciences, Peking University, Beijing 100871, China | 2005 | Science in China(Series F)2005，48，6： | 8 |
| 17 | Stochastic modelling of soil moisture dynamics in a grassland of Qilian Mountain at point scale显示文摘Stochastic modeling of soil moisture dynamics is crucial to the quantitative understanding of plant responses to water stresses,hydrological control of nutrient cycling processes,water competition among plants,and some other ecological dynamics,and thus has become a hotspot in ecohydrology at present.In this paper,we based on the continuously monitored data of soil moisture during 2002―2005 and daily precipitation date of 1992―2006,and tried to make a probabilistic analysis of soil moisture dynamics at point scale in a grassland of Qilian Mountain by integrating the stochastic model improved by Laio and the Monte Carlo method.The results show that the inter-annual variations for the soil moisture patterns at different depths are very significant,and that the coefficient of variance(CV) of surface soil moisture(20 cm) is almost continually kept at about 0.23 whether in the rich or poor rainy years.Interestingly,it has been found that the maximal CV of soil moisture has not always appeared at the surface layer.Comparison of the analytically derived soil moisture probability density function(PDF) with the statistical distribution of the observed soil moisture data suggests that the stochastic model can reasonably describe and predict the soil moisture dynamics of the grassland in Qilian Mountain at point scale.By extracting the statistical information of the historical precipitation data in 1994―2006,and inputting them into the stochastic model,we analytically derived the long-term soil moisture PDF without considering the inter-annual climate fluctuations,and then numerically derived the one when considering the inter-annual fluctuation effects in combination with a Monte-Carlo procedure.It was found that,though the peak position of the probability density distribution significantly moved towards drought when considering the disturbance forces,and its width was narrowed,accordingly its peak value was increased,no significant bimodality was observed in the soil moisture dynamics under the given intensity of random fluctuation disturbance. | LIU Hu,ZHAO WenZhi HE ZhiBin & ZHANG LiJie Linze Inland River Basin Research Station,Chinese Ecosystem Research Network Laboratory of Watershed Hydrology and Ecol-ogy,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China | 2007 | Science China Earth Sciences2007，50，12： | 7 |
| 18 | RRM:An incentive reputation model for promoting good behaviors in distributed systems显示文摘Reputation systems represent soft security mechanisms that complement traditional information security mechanisms. They are now widely used in online e-commerce markets and communities in order to stimulate good behaviors as well as to restrain adverse behaviors. This paper analyzes the limitations of the conversational reputation models and proposes an incentive reputation model called the resilient reputation model(RRM) for the distributed reputation systems. The objective of this reputation model is not only to encourage the users to provide good services and,therefore,to maximize the probability of good transaction outcomes,but also to punish those adverse users who are trying to manipulate the application systems. The simulation results indicate that the proposed reputation model(RRM) could effectively resist against the common adverse behaviors,while protecting the profits of sincere users from being blemished by those adversaries. | ZHANG Hong1,2,DUAN HaiXin1,3 & LIU Wu1,3 1 Tsinghua National Laboratory for Information Science and Technology,Tsinghua University,Beijing 100084,China 2 Department of Computer Science and Technology,Tsinghua University,Beijing 100084,China 3 Network Research Center,Tsinghua University,Beijing 100084,China | 2008 | Science in China(Series F)2008，51，11： | 7 |
| 19 | Quantitative estimation of the shrub canopy LAI from atmosphere-corrected HJ-1 CCD data in Mu Us Sandland显示文摘The leaf area index(LAI) is an important ecological parameter that characterizes the interface between vegetation canopy and the atmosphere.In addition,it is used by most process-oriented ecosystem models.This paper investigates the potential of HJ-1 CCD data combined with linear spectral unmixing and an inverted geometric-optical model for the retrieval of the shrub LAI in Wushen Banner of Inner Mongolia in the Mu Us Sandland.MODTRAN(Moderate Resolution Atmospheric Radiance and Transmittance Model) was used for atmospheric correction.Shrubland was extracted using the threshold of the normalized difference vegetation index,with which water bodies and farmland were separated,in combination with a vegetation map of the People's Republic of China(1:1000000).Using the geometric-optical model,we derive the per-pixel reflectance as a simple linear combination of two components,namely sunlit background and other.The fraction of sunlit background is related to the shrub LAI.With the support of HJ-1 CCD data,we employ linear spectral unmixing to obtain the fraction of sunlit background in an atmospherically corrected HJ image.In addition,we use the measured shrub canopy structural parameters for shrub communities to invert the geometric-optical model and retrieve the pixel-based shrub LAI.In total,18 sample plots collected in Wushen Banner of Inner Mongolia are used for validation.The results of the shrub LAI show good agreement with R2 of 0.817 and a root-mean-squared error of 0.173. | CHEN Wei1,2,CAO ChunXiang1,HE QiSheng1,2,GUO HuaDong3,ZHANG Hao1,2,LI RenQiang4,ZHENG Sheng1,2,XU Min1,2,GAO MengXu1,2,ZHAO Jian1,2,LI Sha1,NI XiLiang1,2,JIA HuiCong1,JI Wei1,TIAN Rong1,2,LIU Cheng1,2,ZHAO YuXing5 & LI JingLu6 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,Beijing 100101,China 2 Graduate University of Chinese Academy of Sciences,Beijing 100049,China 3 Center for Earth Observation and Digital Earth,Chinese Academy of Sciences,Beijing 100190,China 4 China Key Laboratory of Ecological Network Observation and Modeling,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China 5 Ordos Forestry Sand Control Science Institute,Dongsheng 017000,China 6 Inner Mongolia Biomass Thermoelectricity Limited Company,Wushen 017300,China | 2010 | Science China Earth Sciences2010，53，S1： | 6 |
| 20 | 中国科学院生态系统网络观测与模拟重点实验室CERN综合研究中心研究成果与发展显示文摘介绍了中国生态系统研究网络(CERN)综合研究中心成立以来的发展历程和主要研究成果,以及未来研究方向及预期发展。取得的代表性研究成果主要有:CERN动态监测数据与生态系统空间信息数据管理和共享系统的开发、陆地生态系统碳和水热通量观测研究、陆地生态系统碳储量的时空格局特征研究、陆地生态系统多尺度模拟综合集成研究和青藏高原生态系统格局与全球变化相互作用关系研究等。未来的研究方向主要集中在陆地生态系统碳氮水循环及其耦合,区域碳汇功能动态,生态敏感区、脆弱区和过渡区对全球气候变化的响应与适应,生态监测、模拟与生态信息应用以及全球气候变化主要因子对生态系统关键过程的影响。未来除了履行CERN综合研究中心的基本职能外,争取在以上研究方向取得有国际影响的开拓性研究成果。 | Synthesis Research Center of Chinese Ecosystem Research Network,CAS(Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China) | 2010 | 自然资源学报2010，25，9： | 6 |
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