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Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

Science china Earth Sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2 & LI YaoKun3,4 1National Marine Environmental Forecasting Center, beijing 100081, china 2First institute of Oceanography, State Oceanic administration, Qingdao 266061, china 3State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 4Graduate University of Chinese Academy of Sciences, beijing 100049, china 1. National Marine Environmental Forecasting Center Beijing 100081 China2. First Institute of Oceanography State Oceanic Administration Qingdao 266061 China3. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China4. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

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Thermal expansion properties and hygro-scopicity of Y_(2-x)Sm_xW_3O_(12) (x=0.0-0.4) compounds

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Science china(Technological Sciences) 2008年第1期51卷 25-32页

作者： YU ZhouXiang1, PENG Jie2, WANG Hui2, WU MeiMei2, cheng YingZhi2, HU ZhongBo2 & CHEN DongFeng1 1 china institute of Atomic Energy, P.O. Box 275 (30), beijing 102413, china 2 College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, beijing 100049, china china institute of Atomic Energy P.O.Box 275 (30)Beijing 102413China College of Chemistry and Chemical Engineering Graduate University of Chinese Academy of SciencesBeijing 100049China

A novel class of solid solutions of Y2-xSmxW3O12 (x = 0.0–0.4) were synthesized and studied by means of powder X-ray diffraction. All samples crystallize in an ortho- rhombic space group Pnca. The lattice parameters a, b and c of Y2-xSmxW3O12 in- crease with increasing Sm content. Since the compounds of this series hydrate at room temperature, thermogravimetric (TG) analysis was carried out. The result shows that the compound stores less water with increasing Sm content. The thermal expansion properties of Y2-xSmxW3O12 (x = 0.1, 0.3 and 0.4) were investi- gated with high temperature X-ray diffraction. Negative thermal expansion coeffi- cient αl becomes less negative from -6.644×10-6 to -6.211×10-6℃-1 when x changes from 0.1 to 0.4.

关键词： rare earth tungstates negative thermal expansion hygroscopic XRD

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Optimization of mathematical models for thematic maps

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Science china(Technological Sciences) 2010年第S1期53卷 15-24页

作者： QI QingWen1,ZHANG An1,JIANG LiLi1,ZOU XiuPing2,XU Li3 & cheng Xi1,4 1 institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,beijing 100101,china 2 institute of Policy and Management,Chinese Academy of Sciences,beijing 100080,china 3 Taishan University,Taian 271021,china 4 Graduate University of Chinese Academy of Sciences,beijing 100049,china Chinese Acad Sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China Chinese Acad Sci Inst Policy & Management Beijing 100080 Peoples R China Taishan Univ Tai An 271021 Shandong Peoples R China Chinese Acad Sci Grad Univ Beijing 100049 Peoples R China

The thematic map is a major class of maps designed to demonstrate particular features or concepts,functioning as an indispensable tool in geographical *** process of thematic mapping is one into which geographical research goes deeply and *** key activity and course of thematic map production is the use of mathematical models to create thematic data ***,the selection and optimization of mathematical models is in the forefront of thematic map *** theoretical foundations,mechanisms and methods of mathematical model optimization are expounded in this paper,including two approaches,the phase by phase mode and the multi-aim scheme balance *** studies in eco-environment mapping and emergency mapping are described and analyzed,with a hierarchical analysis method being used in the model optimization for eco-environment fragility and sensitivity assessment mapping in Beibuwan (Guangxi) District,the dynamic system (DS) method being used in the model optimization for ecological security adjustment mapping in Xishuang Banna,Yunnan province,and the multi-phase mode being used in the models for forest fire and infectious diseases mapping.

关键词： thematic map mathematic model optimization

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Responses of soil respiration in non-growing seasons to environmental factors in a maize agroecosystem,Northeast china

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Chinese Science Bulletin 2010年第24期55卷 2723-2730页

作者： LI RongPing1,2,3, ZHOU GuangSheng1,4 & WANG Yu1,3 1 State Key Laboratory of Vegetation and Environmental Change, institute of Botany, Chinese Academy of Sciences, beijing 100093, china 2 institute of Atmospheric Environment, china Meteorological administration, Shenyang 110016, china 3 Graduate University of Chinese Academy of Sciences, beijing 100049, china 4 Chinese Academy of Meteorological Sciences, beijing 100081, china State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China institute of Atmospheric Environment China Meteorological Administration Shenyang 110016 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Chinese Academy of Meteorological Sciences Beijing 100081 China

Based on continuous three-year measurements (from 2004 to 2007) of eddy covariance and related environmental factors, environmental controls on variation in soil respiration (Rs) during non-growing season were explored in a maize agroecosystem in Northeast china. Our results indicated that during non-growing seasons, daily Rs was 1.08-4.08 g CO2 m-2 d-1, and the lowest occurred in late November. The average Rs of non-growing season was 456.06 ± 20.01 g CO2 m-2, accounting for 11% of the gross primary production (GPP) of the growing season. Additionally, at monthly scale, the lowest value of Rs appeared in January or February. From the beginning to the end of non-growing season, daily Rs tended to decrease first, and then increase to the highest. There was a significant quadratic curve relationship between Rs and soil temperature at 10 cm depth when soil temperature was more than 0°C (P1), with the explaining ratio of 38%-70%. When soil water content was more than 0.1 m3 m-3, soil moisture at 10 cm depth was significantly parabolically correlated with Rs (P1), explaining the rate of 18%-60%. Based on all the data of soil temperature of more than 0°C, a better model for Rs was established by coupling soil temperature and moisture, which could explain the rate of up to 53%-79%. Meanwhile, the standard error of regression estimation between the values of prediction and observation for Rs could reach 2.7%-11.8%. Rs in non-growing season can account for 22.4% of Rs in growing season, indicating that it plays a critical role in assessing the carbon budget in maize agroecosystem, Northeast china.

关键词：中国东北地区农田生态系统生长季节土壤呼吸环境因素玉米土壤含水量反应

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Numerical simulation of topography effects on the “00.7” severe rainfall in beijing

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Progress in Natural Science:Materials International 2005年第9期15卷 818-826页

作者： ZHANG Chaolin1**, JI Chongping1, KUO Yinghwa2, FAN Shuiyong1, XUAN Chunyi3 and CHEN Min1(1. institute of Urban Meteorology, china Meteorological administration, beijing 100089, china 2. Mesoscale and Microscale Meteorology Division, National Center for Atmospheric Research, Boulder, CO 80307-3000, USA 3. beijing Meteorological Bureau, beijing 100089, china) institute of Urban Meteorology China Meteorological Administration Beijing 100089 China. Mesoscale and Microscale Meteorology Division National Center for Atmospheric Research Boulder CO 80307-3000 USA. beijing Meteorological Bureau Beijing 100089 China

In an effort to study the severe rainfall event of 4—5th July 2000 in beijing (with 24h accumulated precipitation of 240 mm), we perform numerical simulations to investigate this event using the MM5v3.6 model. The model is initialized with the MM5/WRF 3DVAR analysis, which incorporates the ground-based GPS precipitable water vapor, automatic and conventional meteorological observations in its assimilation step. For 24 h accumulated precipitation forecast, the threat scores are 0.72, 0.76, 0.67 and 0.63, for thresholds of 1, 5, 10, and 20 mm, respectively. Holding other factors unchanged, sensitivity experiments were conducted with different topographic resolutions of 110, 50 and 3.7 km to investigate the topographic effects on precipitation over the beijing area. In these sensitivity experiments, we attempt to preserve the realistic orographic distribution in the model topography under the condition of keeping the dynamic-thermodynamic consistency of the initial model atmosphere to the extent possible. Results indicate that the unique topographic distribution and variations in the beijing area play an important role in determining the location, distribution and intensity of heavy precipitation.

关键词： topography heavy rainfall 3DVAR ground-based GPS numerical simulation.

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Debating about the climate warming

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Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2, ZHAO Zongci2, DONG Wenje2 and YANG Bao3 (1.Department of Atmospheric Sciences, School of Physics, Peking University, beijing 100871, china 2. Laboratory for Climate Studies, china Meteorological administration, beijing 100081, china 3. institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 730000, china) [a] Department of Atmospheric Sciences School of Physics Peking University Beijing China [b] Laboratory for Climate Studies China Meterological Administration Beijing China [c] institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2) All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3) The warming from 1975 to 2000 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 20th century.

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Mechanisms of invasive population establishment and spread of pinewood nematodes in china

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Science china(Life Sciences) 2009年第6期52卷 587-594页

作者： XIE BingYan1,cheng XinYue2,SHI Juan3,ZHANG QingWen4,DAI ShuMing1,cheng Fei Xue2 & LUO YouQing3 1 institute of Vegetables and Flowers,Chinese Academy of Agricultural Sciences,beijing 100081,china 2 beijing Normal University,beijing 100875,china 3 beijing Forestry University,beijing 100083,china 4 Chinese Agricultural University,beijing 100094,china 1. institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences Beijing 100081 China 2. beijing Normal University Beijing 100875 China 3. beijing Forestry University Beijing 100083 China 4. Chinese Agricultural University Beijing 100094 China

This paper summarizes the results of our study of the pinewood nematode(Bursaphelenchus xylophi-lus).By population genetic analysis,it was determined that there was no genetic bottle caused by the founder effect and genetic drift in the Chinese invasive *** invasions with large amounts of nematodes from different sources led to rich genetic diversity in the invasive *** high genetic diversity in the invasive process may be one of the genetic mechanisms in its successful *** testing interspecies competition,it was shown that,with high fecundity and a strong competitive ability,*** outcompeted the native species *** in the natural ecosystem during the invasion *** displacement may be one of the ecological mechanisms of ***'s *** addition,an unequal interspecific hybridization with intro-gress was in favor of the invasive species which also accelerated the replacement of *** by *** structures,functions and evolutions of a few important genes that are closely related to the ecological adaptation of pinewood nematodes were studied to explore the molecular mechanism of its ecological ***,the resistance and resilience mechanism of the pine ecosystem invaded by pinewood nematodes was also *** results of these studies uncovered a portion of the genetic and ecological mechanisms of PWN's successful invasion and laid a foundation for further study to obtain a comprehensive interpretation of the mechanisms of the nematode *** results also provided a scientific basis for effectively controlling the occurrence and spread of pine wilt disease which is caused by *** aspects requiring further investigation are considered.

关键词： pinewood nematode bioinvasion genetic diversity ecological adaptation resistance resilience

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Magnetic Field Effects on Quantum-Dot Spin Valves

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Communications in Theoretical Physics 2009年第3期51卷 555-562页

作者： GAO Jin-Hua,~1 SUN Qing-Feng,~1 and XIE Xin-cheng~(1,2)1 beijing National Lab for Condensed Matter Physics and institute of Physics, Chinese Academy of Sciences,beijing 100080, china2 Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA beijing National Lab for Condensed Matter Physics and institute of Physics Chinese Academy of Sciences Beijing 100080 China Department of Physics Oklahoma State University Stillwater Oklahoma 74078 USA

We study the magnetic field effects on the spin-polarized transport of the quantum dot (QD) spin valve inthe sequential tunneling regime. A set of generalized master equation is derived. Based on that, we discuss the collinearand noncollinear magnetic field effects, respectively. In the collinear magnetic field case, we find that the Zeeman splittingcan induce a negative differential conductance (NDC), which is quite different from the one found in previous *** has a critical polarization in the parallel arrangement and will disappear in the antiparallel configuration. In thenoncollinear magnetic field case, the current shows two plateaus and their angular dependence is analyzed. Althoughsometimes the two current plateaus have similar angular dependence, their mechanisms are different. Our formalism isalso suitable for calculating the transport in magnetic molecules, in which the spin splitting is induced not by a magneticGeld but by the intrinsic magnetization.

关键词： spin value spintronics quantum dot

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Biomass estimation and uncertainty analysis based on CBERS-02 CCD camera data and field measurement

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Science china(Technological Sciences) 2005年第S2期48卷 116-128页

作者： CHEN Liangfu1,2, GAO Yanhua1,3, cheng Yu1,3, WEI Zheng1,3, XIAO Qing1,4, LIU Qinhuo1, YU Tao1, LIU Qijing5, GU Xingfa1 & TIAN Guoliang1 1. State Key Laboratory of Remote Sensing Science, institute of Remote Sensing Applications, Chinese Academy of Sciences, beijing 100101, china 2. Geography and Environment College, Jiangxi Normal University, Nanchang 330027, china 3. Graduate University of Chinese Academy of Sciences, beijing 10003., china 4. beijing Research institute of Uranium geology, beijing 100875, china 5. institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, china 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China 2. Geography and Environment College Jiangxi Normal University 330027 Nanchang China 3. Graduate University of Chinese Academy of Sciences 100039 Beijing China 4. beijing Research institute of Uranium geology 100875 Beijing China 5. institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

The study site is located in Qianyanzhou experimental station and the surrounding area. Based on CBERS-02 satellite data and field measurement, we not only discussed the relationship between NDVI and biomass of two species of coniferous plantations, namely, Pinus massoniana Lamb and Pinus elliottii Engelm, but also introduced the biomass models based on NDVI. The comparison between measured biomass in Qianyanzhou and biomass derived from CBERS-02 CCD data showed that it is feasible to estimate biomass based on NDVI. But its limitations cannot be ignored. This kind of model depends on the dominant vegetation species. There are some effect factors in estimating biomass based on NDVI. This paper analyzes these factors based on fine-resolution CBERS-02 CCD data and some conclusions are drawn: In Qianyanzhou, the area with good vegetation coverage, the nonlinearity of NDVI has little influence on scaling-up of NDVI. As a result of surface heterogeneity, scaling-up can cause NDVI within each pixel to change. Because scaling-up can cause pixel attribute to change, the applicability of biomass model is one of the sources of error in estimating biomass.

关键词： NDVI biomass scaling effect scaling-up.

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Grain size record of microparticles in the Muztagata ice core

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Science china Earth Sciences 2006年第1期49卷 10-17页

作者： WU Guangjian1,2, YAO Tandong1,2, XU Baiqin1,2, LI Zheng2, TIAN Lide1,2, DUAN Keqin2 & WEN Linke2 1. Laboratory of Environment and Process on Tibetan Plateau, institute of Tibetan Plateau Research, Chinese Academy of Sciences, beijing 100085, china 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research institute and institute of Tibetan Plateau Research, Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences, china Meteorological administration, Lanzhou 730000, china 1. Laboratory of Environment and Process on Tibetan Plateau Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Key Laboratory of Cryosphere and Environment Jointly Established by Cold and Arid Regions Environmental and Engineering Research Institute and Institute of Tibetan Plateau Research Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences China Meteorological Administration Lanzhou 730000 China

The dust transport and sediment characteristics are discussed based onanalysis of mi-croparticle size and size distribution in the Muztagata ice core at 6350 m a.s.I. Thefiner particles with diameter of 1—5 μm are the dominant fraction in number, while middle andcoarse particles mainly contribute to the total volume. The lognormal distribution characteristicscan be seen for some high concentration samples, showing that model size and standard variation aregreater than that in the Greenland ice cores. However, size-volume distribution of some lowconcentration samples is abnormal. Those distributions reflect the dust deposit process in highmountain glaciers at mid-low latitudes and show differences from those in polar ice sheet.

关键词： Muztagata, ice core, microparticle, dust, size distribution.

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