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Theorem of turbulent intensity and macroscopic mechanism of the turbulence development

Science china Earth Sciences 2007年第5期50卷 789-800页

作者： HU YinQiao1,2, CHEN JinBei3,4 & ZUO HongChao2 1 Gansu Province Key laboratory of Arid Climatic Change and Reducing Disaster, Cold and Arid Regions environment and Engi- neering Institute, Chinese Academy of Sciences, lanzhou 730000, china 2 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Beijing 100029, china 3 Atmospheric Science College, lanzhou university, lanzhou 730000, china 4 resource environment department, lanzhou agriculture university, lanzhou 730060, china Gansu Province Key laboratory of Arid Climatic Change and Reducing Disaster Cold and Arid Regions Environment and Engineering Institute Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Beijing 100029China Atmospheric Science College Lanzhou University Lanzhou 730000 China resource environment department Lanzhou Agriculture University Lanzhou 730060 China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry LAPC Beijing 100029 China

Turbulence is one of the most common nature phenomena in everyday experience, but that is not adequately understood yet. This article reviews the history and present state of development of the turbulence theory and indicates the necessity to probe into the turbulent features and mechanism with the different methods at different levels. Therefore this article proves a theorem of turbulent transpor- tation and a theorem of turbulent intensity by using the theory of the nonequilibrium thermodynamics, and that the Reynolds turbulence and the Rayleigh-Bénard turbulence are united in the theorems of the turbulent intensity and the turbulent transportation. The macroscopic cause of the development of fluid turbulence is a result from shearing effect of the velocity together with the temperature, which is also the macroscopic cause of the stretch and fold of trajectory in the phase space of turbulent field. And it is proved by the observed data of atmosphere that the phenomenological coefficient of turbulent in- tensity is not only a function of the velocity shear but also a function of temperature shear, viz the sta- bility of temperature stratification, in the atmosphere. Accordingly, authenticity of the theorem, which is proved by the theory of nonequilibrium thermodynamics, of turbulent intensity is testified by the facts of observational experiment.

关键词： turbulence nonequilibrium thermodynamics linear thermodynamics atmosphere boundary layer Reynolds turbulence Rayleigh-Bénard turbulence

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Impacts of permafrost changes on alpine ecosystem in Qinghai-Tibet Plateau

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Science china Earth Sciences 2006年第11期49卷 1156-1169页

作者： WANG Genxu1,3 , LI Yuanshou2 , WU Qingbai2 & WANG Yibo3 1. Institute of Mountain Hazards and environment, Chinese Academy of Sciences, Chengdu 610041, china 2. Cold and Arid Regions environmental and Engineering Research Institute, Chinese Academy of Sciences, lanzhou 730000, china 3. resource and environment School, lanzhou university, lanzhou 730000, china Institute of Mountain Hazards and environment Chinese Academy of Sciences Chengdu China resource and environment School Lanzhou University Lanzhou China Cold and Arid Regions environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China

Alpine cold ecosystem with permafrost environment is quite sensitive to climatic changes and the changes in permafrost can significantly affect the alpine ecosystem. The vegetation coverage, grassland biomass and soil nutrient and texture are selected to indicate the regime of alpine cold ecosystems in the Qinghai-Tibet Plateau. The interactions between alpine ecosystem and permafrost were investigated with the depth of active layer, permafrost thickness and mean annual ground temperature (MAGTs). Based on the statistics model of GPTR for MAGTs and annual air temperatures, an analysis method was developed to analyze the impacts of permafrost changes on the alpine ecosystems. Under the climate change and human engineering activities, the permafrost change and its impacts on alpine ecosystems in the permafrost region between the Kunlun Mountains and the Tanggula Range of Qinghai-Tibet Plateau are studied in this paper. The results showed that the per- mafrost changes have a different influence on different alpine ecosystems. With the increase in the thickness of active layer, the vegetation cover and biomass of the alpine cold meadow exhibit a significant conic reduction, the soil organic matter content of the alpine cold meadow ecosystem shows an exponential decrease, and the surface soil materials become coarse and gravelly. The alpine cold steppe ecosystem, however, seems to have a relatively weak relation to the permafrost environment. Those relationships resulted in the fact that the distribution area of alpine cold meadow decreased by 7.98% and alpine cold swamp decreased by 28.11% under the permafrost environment degradation during recent 15 years. In the future 50 years the alpine cold meadow ecosystems in different geomorphologic units may have different responses to the changes of the permafrost under different climate warming conditions, among them the alpine cold meadow and swamp ecosystem located in the low mountain and plateau area will have a relatively

关键词： permafrost environment, alpine cold ecosystem, statistics relationship, climate change, impacts, Qinghai-Tibet Plateau.

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Impact of land-use change on hydrological processes in the Maying River basin, china

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Science china Earth Sciences 2006年第10期49卷 1098-1110页

作者： WANG Genxu1,3, ZHANG Yu2, LIU Guimin2 & CHEN Lin3 1. Institute of Mountain Hazards and environment, Chinese Academy of Sciences, Chengdu 610041, china 2. Cold and Arid Regions environmental and Engineering Research Institute, Chinese Academy of Sciences, lanzhou 730000, china 3. resource and environment School, lanzhou university, lanzhou 730000, china Institute of Mountain Hazards and environment Chinese Academy of Sciences Chengdu China resource and environment School Lanzhou University Lanzhou China Cold and Arid Regions environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China

Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of china. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest china, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors, i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large ar- eas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 28.12%, a base flow decline of 35.32%, a drop in the maximum peak discharge of 35.77%, and mean discharge decreases in spring and autumn of 36.05% and 24.87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73%-81%, and that to the influence of base flow reaching 62%-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water resources and the proper development of the entire catchment.

关键词： land-use change, arid inland river catchment, hydrological process, impact, Maying River.

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Effect of molecular weight of dissolved organic matter on toxicity and bioavailability of copper to lettuce

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Journal of environmental Sciences 2010年第12期22卷 1960-1965页

作者： Xudong Wang,Xianni Chen,Shuai Liu,Xizu Ge College of resource and environment,Northwest agriculture and Forestry university,Shaanxi 712100,china College of resource and environment Northwest Agriculture and Forestry University Shaanxi 712100 Chin

To clarify the effects of molecular weight of dissolved organic matter （DOM） on the toxicity and bioavailability of copper （Cu） to plants, DOM extracted from chicken manure was ultra-filtered into four fractions according to their molecular weights by means of sequential-stage ultrafiltration technique. Lettuce seeds were germinated by being exposed to the solutions containing Cu^2＋ with or without different fractions of DOM. The concentration of copper in roots, leaves, sprouts and the length of roots were investigated. The results showed that not all fractions of DOM could improve copper availability or toxicity. The fraction of DOM with larger molecular weight more than 1 kDa had higher complexation stability with Cu^2＋ and caused lower concentration of free Cu^2＋ ion in the solution of copper plus the fraction, resulting in lower availability and toxicity of copper to lettuce, but the fraction with molecular weight less than 1 kDa had the opposite function. Therefore, the molecular weight of 1 kDa may be the division point to determine DOM to increase or decrease copper availability and toxicity.

关键词： fraction of dissolved organic matter complexation stability coooer availability

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Effects of free iron oxyhydrates and soil organic matter on copper sorption-desorption behavior by size fractions of aggregates from two paddy soils

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Journal of environmental Sciences 2009年第5期21卷 618-624页

作者： WANG Fang, PAN Genxing, LI Lianqing Institute of resource, Ecosystem and environment of agriculture, Nanjing Agricultural university, Nanjing 210095, china. Institute of resource Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China

Effects of free iron oxyhydrates （Fed） and soil organic matter （SOM） on copper （Cu^2＋） sorption-desorption behavior by size fractions of aggregates from two typical paddy soils （Ferric-Accumulic Stagnic Anthrosol （Soil H） and Gleyic Stagnic Anthrosol （Soil W）） were investigated with and without treatments of dithionite-citrate-bicarbonate and of H2O2. The size fractions of aggregates were obtained from the undisturbed bulk topsoil using a low energy ultrasonic dispersion procedure. Experiments of equilibrium sorption and subsequent desorption were conducted at soil water ratio of 1：20, 25℃. For Soil H, Cu^2＋ sorption capacity of the DCB-treated size fractions was decreased by 5.9% for fine sand fraction, by 40.4% for coarse sand fraction, in comparison to 2.9% for the bnlk sample. However, Cu^2＋ sorption capacities of the H2O2-treated fractions were decreased by over 80% for the coarse sand fraction and by 15% for the clay-sized fraction in comparison to 88% for bulk soil. For Soil W, Cu^2＋ sorption capacity of the DCB-treated size fraction was decreased by 30% for the coarse sand fraction and by over 75% for silt sand fraction in comparison to 44.5% for the bulk sample. Cu^2＋ sorption capacities of the H2O2-treated fractions were decreased by only 2.0% for the coarse sand fraction and by 15% for the fine sand fraction in comparison to by 3.4% for bulk soil. However, Cu^2＋ desorption rates were increased much in H2O2-treated samples by over 80% except the clay-sized fraction （only 9.5%） for Soil H. While removal of SOM with H2O2 tendend to increase the desorption rate, DCB- and H2O2-treatments caused decrease in Cu^2＋ retention capacity of size fractions, Particularly, there hardly remained Cu^2＋ retention capacity by size fractions from Soil H after H2O2 treatment except for clay-sized fraction. These findings supported again the dominance of the coarse sand fraction in sorption of metals and the preference of absorbed metals bound to SOM in differently stabilized

关键词： paddy soils Cn^2+ sorption-desorption soil organic matter free iron oxyhydrates size fraction of aggregates

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Variation of grain Cd and Zn concentrations of 110 hybrid rice cultivars grown in a low-Cd paddy soil

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Journal of environmental Sciences 2009年第2期21卷 168-172页

作者： SHI Jing,LI Lianqing,PAN Genxing Institute of resource,Ecosystem and environment of agriculture,Nanjing Agricultural university,Nanjing 210095,china. Institute of resource Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China

Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of china had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil （Entic Haplaquept） with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer （GFAAS） and flame atomic adsorption spectrophotometer （AAS） respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods （MOHC and SSC, 2005）, calculated potential risk of food Cd exposure with ＂Zn hungry＂ through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South china using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.

关键词： rice cultivar rice grain cadmium zinc genotype difference

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Relation of lead adsorption on birnessites with different average oxidation states of manganese and release of Mn^(2+)/H^+/K^+

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Journal of environmental Sciences 2009年第4期21卷 520-526页

作者： ZHAO Wei, FENG Xionghan, TAN Wenfeng, LIU Fan, DING Shuwen Key Laboratory of Subtropical agriculture resource & environment, Ministry of agriculture of china, Huazhong Agricultural university, Wuhan 430070, china. Key Laboratory of Subtropical agriculture resource & environment Ministry of Agriculture of China Huazhong Agricultural University Wuhan 430070 China

The characteristics of Pb^2＋ adsorption on the surface of birnessites with different average oxidation states （AOS） of Mn, synthesized under acidic and alkali conditions, were investigated. The results indicated that the amount of adsorbed Pb^2＋ increased with the increase of Mn AOS in birnessites. The amount of Pb〉 adsorbed positively correlated with the amount of released Mn^2＋, H^＋, and K^＋（r = 0.9962 〉 0.6614, n = 14, ct = 0.01）. The released Mn^2＋, H^＋, and K^＋ were derived mostly from the corresponding cations adsorbed on the vacant sites. The maximum amount of adsorbed Pb^2＋ increased with the increasing vacant cation sites, leading to an increase of the total amount of released Mn^2＋, H^＋, and K^＋, and the increased likelihood for two Pb^2＋ adsorbed in the region of one side of a vacant site.

关键词： pb^2+ adsorption birnessite vacant site cation release

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Influence of Particle Size on Magnetic Properties of Soils in Zhejiang Province, china

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Pedosphere 2000年第1期10卷 81-88页

作者： LU SHENGGAO (College of environment and resource, Zhejiang university, Hangzhou 510029 (china)) 浙江大学浙江杭州 310029

The relationship between magnetic properties and particle size of soils derived from metamorphic rock, basalt, granite, Quaternary red clay, limestone and mudstone from Zhejiang Province, East china was studied. Based on the variations of the mass magnetic susceptibility (X), anhysteretic remanent magnetization (ARM), and saturation isothermal remanent magnetization (SIRM) with soil particle size, the relationship could be classified into three groups. For the soils derived from metamorphic rock and basalt, magnetic values were the highest in the gravel and coarse sand fractions and decreased with decreasing soil particle size. The soils derived from sedimentary rock had a bimodal distribution of magnetic values, with peaks in 1-0.5 and 0.005-0.000 5 mm fractions. The soil developed on granite was characterized by a peak of magnetic value in 0.001-0.000 5 mm fractions. Frequency-dependent susceptibility (Xfd ) and ratics of magnetic parameters (ARM/X, SIRM/X and SIRM/ARM) of soil particle fractions showed that variations in ferrimagnetic grain size paralleled those in particle size. Xfd peaked in clay fraction and decreased with increasing particle size, irrespective of soil parent materials. The acquisition curves of IRM and demagnetization parameter of different soil particles indicated that there were different magnetic minerals assemblages in different particle fractions.

关键词： soil particle soil parent material magnetic property Zhejiang Province

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Evidence from carbon isotope measurements for biological origins of individual long-chain n-alkanes in sediments from the Nansha Sea,china

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Chinese Science Bulletin 2002年第7期47卷 578-581页

作者： DUAN Yi & WANG ZhipingState Key Laboratory of Gas Geochemistry, lanzhou Institute of Geology, Chinese Academy of Sciences, lanzhou 730000, china Institute of environmental Science, Beijing Normal university, Beijing 100875, china State Key Laboratory of Gas Geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou China Institute of environmental Science Beijing Normal University Beijing China

Carbon isotopes are measured for individual long-chain n-alkanes in sediments from the Nansha Sea. The features of carbon isotopic compositions of individual n-alkanes and their origins are studied. The results show that the long-chain n-alkanes have a light carbon isotopic composition and a genetic feature of mixing sources, and low-latitude higher plants and microbes are considered to be their main end member sources. Based on the abundances and carbon isotopic compositions of individual n-alkanes, the fractional contributions of the two end member sources to individual n-alkanes are quantitatively calculated by using a mixing model. The obtained data indicate that the fractional contributions of the two biological sources are different in the three samples. A trend is that the contribution of microbes increases with the depth. These results provide the theory basis and quantitatively studied method for carbon isotopic applied research of individual n-alkanes.

关键词： modern marine sediment individual n-alkane carbon isotopic composition biological source.

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Mapping the Farming-pastoral Ecotones in china

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Journal of Mountain Science 2009年第1期6卷 78-87页

作者： ZHANG Jian WEI Jie CHEN Quangon Institute of Mountain Hazards and environment Chinese Academy of Sciences Chengdu 610041 China Tourism College Chongqing Normal University Chongqing 400047 China School of PastoralAgricultural Science and Technology Lanzhou University Lanzhou 730020 China Graduate university of the Chinese Academy of Sciences Beijing 100049 China

Conventional farming-pastoral ecotones methods of delineating were not quantitative and could not fully show their spatial distribution. The present paper attempts to develop quantitative methods for mapping farming-pastoral ecotones in china. Nine indicators, related to temperature, precipitation and altitude aspects, were selected to quantify ecological susceptibility of vegetation （crops and forage）. Methods of analytic hierarchy process （AHP） and expert score ranking combined with fuzzy set theory were applied to assign the weight for each indicator and to define the membership functions. The geographic information system （GIS） was used to manage the spatial database and conduct the spatial analysis. According to the spatial calculation of evaluation model integrated with GIS, the ecological susceptibility of vegetation （crops and forage） was mapped. Three different zones, pastoral area, farming-pastoral ecotones and farming area, were classified by spatial cluster analysis and the maximum likelihood classification for the numeric map of vegetation ecological susceptibility by GIS. This map was validated by the economic statistical result based on the ratio of the output value from animal husbandry in total output value of agriculture by the National Bureau of Statistics in china, indicating that the mapping of the farming-pastoral ecotones may be accepted.

关键词： AHP Farming-pastoral ecotone Fuzzyset theory GIS

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