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Development of environmental monitoring satellite systems in china

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Science china Earth sciences 2010年第S1期53卷 1-7页

作者： LI GuoPing1 & CAO ChunXiang2 1 School of Earth and Space sciences,peking university,beijing 100871,china 2 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 1. School of Earth and Space sciences Peking University Beijing 100871 China2. 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

With the increase in global environmental problems,the necessity and urgency of remote sensing technology being applied to environmental monitoring has been widely recognized around the *** has launched the environment and disaster monitoring and forecasting small satellite constellation HJ-1A/B and the FY3 atmosphere and environmental satellite,but they still cannot fully satisfy requirements for environmental *** paper summarizes the current status of satellite environmental monitoring in china and the existing problems of inadequate load design and low data utilization efficiency,and discusses the demand for environmental monitoring *** on the development of foreign satellite systems for environmental monitoring,the future development and key tasks of the environmental monitoring satellite system in china is discussed,as are some related initiatives.

关键词： environmental satellite environmental monitoring global climate change specialty load satellite system

Flux of dimethylsulfide in the Jiaozhou Bay,china

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Journal of Environmental sciences 1997年第1期9卷 80-85页

作者： Hu Min Tang Xiaoyan Center of Environmental sciences,peking university,beijing 100871,chinaLi Jinlong Yu Zhongju Department of Technical Physics,peking university,beijing 100871,china Center of Environmental sciences Peking University Beijing 100871 China Department of Technical Physics Peking University Beijing 100871 China

Seasonal measurements of dimethylsulfide(DMS)in surface waters were carried out during 1993-1994 in the Jiaozhou Bay.A seasonal variation is observed for DMS concentrations in seawater,ranging from 0.6 to 8.97 nmol S/L with the highest values in spring.A factor of 4 was measured for DMS concentrations with mean concentrations of 5.85 nmol S/L or 6.58 nmol S/L in spring and 1.40nmol S/L in winter.A sea-to-air flux of DMS also showed a seasonal variation.

关键词： dimethyl sulfide flux seawater atmosphere.

On the Markov equivalence of maximal ancestral graphs

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Science china Mathematics 2005年第4期48卷 548-562页

作者： ZHAO Hui, ZHENG Zhongguo & LIU Baijun School of Mathematical sciences, peking university, beijing 100871, china Department of Statistics, Central china Normal university, Wuhan 430079, china 1. School of Mathematical sciences Peking University 100871 Beijing China

Necessary and sufficient conditions for a maximal ancestral graph (MAnG)to be Markov equivalent to another MAnG and to a DAG are provided respectively. Also a polynomial-time algorithm for converting a MAnG into its e... 详细信息

关键词： maximal ancestral graph, Markov equivalence, minimal collider path, m-separation.

Heterogeneous reaction of SO_2 on TiO_2 particles

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Science china Chemistry 2010年第12期53卷 2637-2643页

作者： SHANG Jing,LI Jia & ZHU Tong State Key Joint Laboratory of Environmental Simulation and Pollution Control college of Environmental sciences and Engineering,peking university,beijing 100871,china 1. State Key Joint Laboratory of Environmental Simulation and Pollution Control college of Environmental sciences and Engineering Peking University Beijing 100871 China

The heterogeneous reaction of SO2 on TiO2 particles was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).The influences of the oxygen concentration,relative humidity (RH),and ultraviolet (UV) light illumination (λ=365 nm) intensity on the reaction were *** main product of the heterogeneous reaction of SO2 on TiO2 particles was sulfate with UV illumination and sulfite without *** production of sulfate was promoted significantly with UV illumination or water,and there was a synergistic effect when both were *** the dry system without UV,the heterogeneous reaction of SO2 on TiO2 particles was found to be second-order for SO2 and the initial uptake coefficient,BET,was determined to be 1.94 × *** UV and RH=40%,the reaction order was first-order and the initial uptake coefficient was 1.35 × 10-5.

关键词： SO2 TiO2 DRIFTS heterogeneous oxidation

Calculation of traversal time in tunneling by double-wave theory

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Chinese Science Bulletin 1998年第9期43卷 723-727页

作者： HUANG Xiangyou Department of Physics, peking university, beijing 100871, china Department of Physis Peking University Beijing China

Becausethe information contained in a wave function is not enough to describe an individual particle, the suggestion to define the state of a particle by two-wave functions is used. In the double-wave description, a general formula telling the traversal time of a particle in tunneling is obtained. When the double-wave description over an initial parameter is averaged , it reduces to the usual description. Two new relations between the transmission and the reflected coefficients are founded in the new cescription.

关键词： tunneling double-wave theory ensemble.

Heterogeneous reactions of gaseous methanesulfonic acid with calcium carbonate and kaolinite particles

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Science china Chemistry 2010年第12期53卷 2657-2662页

作者： TANG MingJin,LI MengQiu & ZHU Tong State Key Joint Laboratory of Environmental Simulation and Pollution Control college of Environmental sciences and Engineering,peking university,beijing 100871,china 1. State Key Joint Laboratory of Environmental Simulation and Pollution Control college of Environmental sciences and Engineering Peking University Beijing 100871 China

Heterogeneous reactions of gaseous methanesulfonic acid (MSA) with calcium carbonate (CaCO3) and kaolinite particles at room temperature were investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC).Methanesulfonate (MS-) was identified as the product in the condensed phase,in accordance with the product of the reaction of gaseous MSA with NaCl and sea salt *** the concentration of gaseous MSA was 1.34 × 10-13 molecules cm-3,the uptake coefficient was (1.21 ± 0.06) × 10-8 (1) for the reaction of gaseous MSA with CaCO3 and (4.10 ± 0.65) × 10 10 (1) for the reaction with *** uptake coefficients were significantly smaller than those of the reactions of gaseous MSA with NaCl and sea salt particles.

关键词： gaseous MSA heterogeneous reaction calcium carbonate kaolinite

Simulating the impacts of climate variation and land-cover changes on basin hydrology: A case study of the Suomo basin

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Science china Earth sciences 2005年第9期48卷 1501-1509页

作者： CHEN Junfeng1,2, LI Xiubin2 & ZHANG Ming2 1. Institute of Remote Sensing & GIS, peking university, beijing 100871, china 2. Institute of Geographical sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101, china 1. Institute of Remote Sensing & GIS Peking University 100871 Beijing China 2. Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing Chin

Impacts of land cover changes on watershed hydrology have been a long-term academic concern with acute dispute. But little attention has been paid to such effects on mesoscale river basins, where the society has a closer link to river hydrology. The present study focuses on a mesoscale river basin, the Suomo Basin that is located on the upper reaches of the Yangtze River. Land covers in the basin in the years 1970, 1986 and 1999 were mapped. A lumped hydrologic model, CHARM, and a distributed hydrologic model, SWAT, were used to model the impacts of both land-cover change and climate variation on river runoff during the past four decades. The results show that the contribution of climate variation to the change of runoff regime makes up 60%―80%, while that of land cover changes only 20%.

关键词： climate variation, land-cover changes, Suomo Basin, CHARM model, SWAT model.

Two applications of generalized Carleson measures to meromorphic Besov-type spaces

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Chinese Science Bulletin 1998年第15期43卷 1260-1264页

作者： TAN Haiou 1 and XIAO Jie 2 1. Department of Mathematics, Wuyi university, Jiangmen 529020, china 2. School of Mathematical sciences, peking university, beijing 100871, china Department of Mathematics Wuyi University Jiangmen China School of Mathematical sciences Peking University Beijing China

The generalized Carleson measures are used to characterize the meromorphic Besov_type spaces and to explore some inclusions between these spaces.

关键词： generalized Carleson measures meromorphic Besov_type spaces.

“Tali Glaciation” on Massif Diancang

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Science china Earth sciences 2007年第11期50卷 1685-1692页

作者： YANG JianQiang1, CUI ZhiJiu2, YI ChaoLu1, SUN JiMin3 & YANG LiRong3 1 Institute of Tibetan Plateau Research, Chinese Academy of sciences, beijing 100085, china 2 college of Environmental sciences, peking university, beijing 100871, china 3 Institute of Geology and Geophysics, Chinese Academy of sciences, beijing 100029, china 1. Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. college of Environmental sciences Peking University Beijing 100871 China 3. Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The term of ''Tali Glaciation'' is nominated from Massif Diancang in Yunnan Province. The confusing process of the term''s being put forward is confirmed through literature checking. Based on several times of field trip, the glacial landforms in this region are studied in detail, and the magnitude of the glaciation was determined. According to the numerical ages from TL, AIMS ^(14)C and OSL dating, the earliest glacial advance on Massif Diancang occurred at 30—40 ka BP, followed by the advances at the last stage of the last glaciation, the late glacial and neoglations in turn, until glaciers vanished at 1.2—1.5 ca. a BP in this region. It can be concluded that glaciers were limited above 3600 m a.s.l., and no glaciers existed on the lower part and adjacent mountains since the last glaciation.

关键词： Massif Diancang,Tali Glaciation,glacial landform,glaciation sequence,numerical dating