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vertical distribution characteristics of soil saturated hydraulic conductivity under different land use patterns in the Mu Us sandy land

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地球环境学报 2024年第4期15卷 665-674页

作者： LIU Xingting QIAO Jiangbo YANG Tao MA Yali TIAN Hanyang HAN Xiaoyang ZHU Yuanjun Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China Shaanxi Academy of Forestry Xi’an 710082China Engineering Technology Research Center for Amygdalus Pedunculata National Forestry and Grassland AdministrationYulin 719000China

Background,aim,and scope Soil saturated hydraulic conductivity(K_(s))is a key parameter in the hydrological cycle of soil;however,we have very limited understanding of K_(s)characteristics and the factors that inf luence this key parameter in the Mu Us sandy land(MUSL).Quantifying the impact of changes in land use in the Mu Us sandy land on K_(s)will provide a key foundation for understanding the regional water cycle,but will also provide a scientific basis for the governance of the *** and methods In this study,we determined K_(s)and the basic physical and chemical properties of soil(i.e.,organic matter,bulk density,and soil particle composition)within the first 100 cm layer of four different land use patterns(farmland,tree,shrub,and grassland)in the *** vertical variation of K_(s)and the factors that influence this key parameter were analyzed and a transfer function for estimating K_(s)was established based on a multiple stepwise regression *** The K_(s)of farmland,tree,and shrub increased gradually with soil depth while that of grassland remained *** K_(s)of the four patterns of land use were moderately variable;mean K_(s)values were ranked as follows:grassland(1.38 mm·min^(-1))vertical distribution trend for K_(s)in farmland is known to be predominantly influenced by cultivation,fertilization,and other *** general aim is to improve the water-holding capacity of shallow soil on farmland(0-30 cm in depth)to conserve water and nutrients;research has shown that the K_(s)of farmland increases with soil *** root gro

关键词： Mu Us sandy land saturated hydraulic conductivity vertical distribution transfer function

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vertical distribution of sediment concentration

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第11期9卷 1560-1566页

作者： Sai-hua HUANG Zhi-lin SUN Dan XU Shan-shan XIA Department of Hydraulic and Ocean Engineering Zhejiang University Hangzhou 310058 China

A simple formula is proposed to predict the vertical distribution of a suspended load concentration in a 2D steady turbulent flow. The proposed formula significantly improves the well-known Rouse formula where sediment concentration has an infinitely large value at the channel bottom and a zero value at the water surface. Based on this formula and the logarithmic ve- locity profile, a theoretical elementary function for the transport rate of a suspended load is developed. This equation improves the Einstein equation in which the unit-width suspended sediment discharge must be solved by numerical integration and a contra- diction between the lower limit of the integral and that of velocity distribution exists.

关键词： Sediment concentration vertical distribution Suspended load Sediment discharge

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vertical distribution and temporal evolution of formaldehyde and glyoxal derived from MAX-DOAS observations:The indicative role of VOC sources

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Journal of Environmental Sciences 2022年第12期34卷 92-104页

作者： Qianqian Hong Cheng Liu Qihou Hu Yanli Zhang Chengzhi Xing Jinping Ou Wei Tan Haoran Liu Xiaoqing Huang Zhenfeng Wu School of Environment and Civil Engineering Jiangnan UniversityWuxi 214122China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Key Lab of Environmental Optics&Technology Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Department of Precision Machinery and Precision Instrumentation University of Science and Technology of ChinaHefei 230026China Anhui Province Key Laboratory of Polar Environment and Global Change University of Science and Technology of ChinaHefei 230026China Guangdong Key Laboratory of Environmental Protection and Resources Utilization State Key Laboratory of Organic GeochemistryGuangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality Guangzhou 510632China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China

Formaldehyde(HCHO)and glyoxal(CHOCHO)are important oxidization intermediates of most volatile organic compounds(VOCs),but their vertical evolution in urban areas is not well *** profiles of HCHO,CHOCHO,and nitrogen dioxide(NO_(2))were retrieved from ground-based Multi-Axis Differential Optical Absorption Spectroscopy(MAXDOAS)observations in Hefei,*** and CHOCHO vertical profiles prefer to occur at higher altitudes compared to NO_(2),which might be caused by the photochemistry-oxidation of longer-lived VOCs at higher *** means of HCHO concentrations were higher in summer,while enhanced amounts of NO_(2)were mainly observed in *** exhibited a hump-like seasonal variation,with higher monthly-averaged values not only occurred in warm months(July-August)but also in cold months(November-December).Peak values mainly occurred during noon for HCHO but emerged in the morning for CHOCHO and NO_(2),suggesting that HCHO is stronger link to photochemistry than *** further use the glyoxal to formaldehyde ratio(GFR)to investigate the VOC sources at different *** lowest GFR value is almost found in the altitude from 0.2 to 0.4 km,and then rises rapidly as the altitude *** GFR results indicate that the largest contributor of the precursor VOC is biogenic VOCs at lower altitudes,while at higher altitudes is anthropogenic *** findings provide a lot more insight into VOC sources at vertical direction,but more verification is recommended to be done in the future.

关键词： Formaldehyde Glyoxal MAX-DOAS vertical distribution VOC

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vertical distribution of Soil Carbon, Nitrogen, and Phosphorus in Typical Chinese Terrestrial Ecosystems

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Chinese Geographical Science 2015年第5期25卷 549-560页

作者： CHAI Hua YU Guirui HE Nianpeng WEN Ding LI Jie FANG Jiangping Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Agriculture and Animal Husbandry College of Tibet University

Characterization of the vertical distribution of soil organic carbon(C), nitrogen(N), and phosphorus(P) may improve our ability to accurately estimate soil C, N, and P storage. Based on a database of 21 354 records in 74 long-term monitoring plots from 2004 to 2013 in the Chinese Ecosystem Research Network(CERN), we built fitting functions to quantify the vertical distribution of soil C, N, and P(up to 100 cm depth) in the typical Chinese terrestrial ecosystems. The decrease of soil C, N, and P content with depth can be well fitted with various mathematical functions. The fitting functions differed greatly between artificial(agriculture) and natural(desert, forest, and grassland) ecosystems, and also differed with respect to soil C, N, and P content. In both the artificial and natural ecosystems, the best fitting functions were exponential functions for C, quadratic functions for N, and quadratic functions for P. Furthermore, the stoichiometric ratios of soil C, N, and P were ranked in descending order: grassland > forest > agriculture > desert, and were also associated with climate. This study is the first to build the fitting functions for the profile distribution of soil C, N, and P in China at a national scale. Our findings provide a scientific basis to accurately assess the storage of C, N, and P in soils at a large scale, especially for the integrative analysis of historical data.

关键词： soil profile storage stoichiometry vertical distribution China

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vertical distribution and Seasonal Dynamics of Fine Root Parameters for Apple Trees of Different Ages on the Loess Plateau of China

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Agricultural Sciences in China 2010年第1期9卷 46-55页

作者： GAN Zhuo-ting ZHOU Zheng-chao LIU Wen-zhao Key Laboratory of Disaster Survey and Mechanism Simulation of Shaanxi Province/Baoji University of Arts and Sciences Baoji 721007 P.R. China Institute of Soil and Water Conservation Chinese Academy of Sciences/Ministry of Water Resources/Northwest A&F University Yangling 712100 P.R.China College of Tourism and Environmental Sciences Shaanxi Normal University Xi'an 710062 P.R.China

The vertical distribution pattern and seasonal dynamics of fine root parameters for the apple trees of different ages （3, 10, 15, and 20 years old） on the Loess Plateau of China were studied. Soil coring method was used to determine the vertical distribution and seasonal dynamics of fine roots at different root radial distances （1.0, 1.5, and 2.0 m from the main tree trunk）. The fine root biomass density （FRD）, fine root length density （RLD）, and specific root length （SRL）, as well as soil water content and soil temperature were also measured. The FRD and RLD for the 10, 15, and 20 years old trees reached peak values in the 20-30 cm soil layer. For the 3 years old tree, the highest FRD and RLD were observed in the 10-20 cm soil layer. The FRD and RLD decreased with increased soil depth from the 10-20 or 20-30 cm soil layer for all age apple trees. The SRL declined with the increase of tree age. The FRD at the 1.0 m radial distance from the main tree trunk was higher than that at other radial distances in the 3 and 10 years old orchard. However, in the 15 and 20 years old orchards, especially the 20 years old orchard, the FRD at the 2.0 m radial distance was nearly equal to or higher than that at the 1.0 and 1.5 m radial distances. For all the root radiuses or the tree ages, the FRD, RLD, and SRL were the highest in spring and the lowest in autumn. The age of an apple tree does not affect the vertical distribution pattern but the biomass of fine roots and the SRL. Radial distance affects the root horizontal distribution of 3 and 10 years old trees but the 15 and 20 years old trees. Additionally, effects of soil temperature and soil moisture on fine root distribution or seasonal dynamics are not significant.

关键词： fine root vertical distribution seasonal dynamics apple tree Loess Plateau

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vertical distribution of Soil Nematode Communities under Different Tillage Systems in Lower Reaches of Liaohe River

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Chinese Geographical Science 2010年第2期20卷 106-111页

作者： HOU Xuekun HU Ning ZHANG Xiaoke LIANG Lei ZHAI Ruichang Liaoning Key Laboratory of Soil Environmental Quality and Agro-product Safety Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China College of Plant Sciences and Technology Heilongjiang August First Reclamation University Daqing 163319 China College of Resources and Environment Liaoning University Shenyang 110036 China

vertical distribution of soil nematode communities under conventional tillage (CT),no-tillage (NT) and fallow field (FF) treatments in the Lower Reaches of the Liaohe River was investigated at six soil depths (0-5 cm,5-15 cm,15-30 cm,30-50 cm,50-75 cm and 75-100 cm). The results show that total nematode abundance gradually decreases with depth,and the highest number of total nematodes is observed at 0-5 cm depth under NT and FF treatments. The number of fungivores and plant parasites is significantly higher under FF and NT treatments than under CT treatment at the 0-5 cm depth. There is significant soil depth effect on the abundances of bacterivores and omnivores-predators,which exhibits a similar trend to that of total nematodes; whereas,no significant tillage effect is found. Tillage effect on soil nematode communities can be reflected by values of relative tillage response of index V. Results of index V indicate that total nematodes,bacterivores,fungivores and plant parasites are mildly inhibited,and omnivores-predators is moderately inhibited under CT treatment; while,under FF treatment total nematodes is mildly,and fungivores and plant parasites are moderately stimulated,respectively.

关键词： soil nematode tillage system vertical distribution tillage response

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vertical distribution of Momentum Exchange Coefficient and Sediment Concentration in Estuarine and Coastal Waters

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China Ocean Engineering 2010年第4期24卷 677-692页

作者：黄惠明王义刚闻云呈祝慧敏 Key Laboratory of Coastal Disaster and Defense Ministry of EducationHohai University Nanjing Hydraulic Research Institute

vertical structures of momentum exchange coefficient and sediment concentration are the keys in the research on es- tuarine and coastal suspended sediment transport. Based on the parabolic mixing length distribution pattern, the distribu- tion pattern of vertical momentum exchange coefficient which is suitable for estuarine and coastal waters is constructed. A compari^n with steady flow and measured momentum exchange coefficient during one tidal cycle in the Menai Strait of England shows that the result of this pattern is closer to the measured values than those of commonly used Rouse＇ s and van Rijn＇s patterns, and the pattern is also suitable for estuarine and coastal waters. Successively, based on the precon- dition that momentum exchange coefficient is equivalent to sediment turbulent diffusion coefficient, and combining with the Diffusion Theory, we obtain the exponential vertical distribution pattern of sediment concentration, which is also suitable for estuafine and coastal waters, Thereby, using measured vertical stratified sediment concentration data of the South and the North Passages of the Yangtze Estuary and Zhoushan archipelago waters for fitting calculation, and comparing the results with those from Rouse＇s （1938） and Zhang et al. ＇s （1989） formulas, the results show that the exponential vertical distribution pattern of sediment concentration obtained in the present study not only overcomes the defect of Rouse＇s formula that the surface sediment concentration will be 0, but also has a holistic higher precision along the vertical lines than those of Rouse＇s and Zhang et al. ＇s formulas.

关键词： estuary and coast parabolic mixing length vertical distribution momentum exchange coefficient sedimentconcentration

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vertical distribution and Seasonal Fluctuation of Nematode Trophic Groups as Affected by Land Use

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Pedosphere 2006年第2期16卷 169-176页

作者： MENG Fan-Xiang OU Wei LI Qi JIANG Yong WEN Da-Zhong Key Laboratory of Terrestrial Ecological Process Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 （China）. Graduate School of the Chinese Academy of Sciences Beijing 100039 （China）

A field investigation was conducted at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences, in an aquic brown soil of Northeast China under three land use types (cropland, abandoned cropland, and woodland) in order to evaluate whether the vertical distribution and seasonal fluctuation for the number of total nematodes and trophic groups could reflect soil ecosystem differences and to determine the relationships between soil chemical properties and soil nematodes. The majority of soil nematodes were present in the 0-20 cm soil layers, and for these land use types plant parasites were the most abundant trophic group. In the abandoned cropland the numbers of plant parasites reached a peak on the August sampling date, whereas the cropland and woodland peaked on the October sampling date. Meanwhile, in all land use types the number of total nematodes, bacterivores, plant parasites, and omnivores-predators was negatively (P < 0.05, except for bacterivores in cropland, which was not significant) correlated with bulk density, and positively (P < 0.05, except for fungivores in abandoned cropland, which was not significant) correlated with total organic carbon and total nitrogen.

关键词： aquic brown soil land uses soil nematode trophic groups vertical distribution

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vertical distribution and Transport of Aerosols during a Dust Event in Xinjiang,Northwest China

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Journal of Meteorological Research 2023年第3期37卷 387-403页

作者： Mengzhu XU Jianli DING Jie LIU Fangqing LIU Xiaoye JIN Yi QU College of Geography and Remote Sensing Sciences Xinjiang UniversityUrumqi 800046 Xinjiang Key Laboratory of Oasis Ecology Xinjiang UniversityUrumqi 830046 Key Laboratory of Smart City and Environment Modeling of Higher Education Institutes Xinjiang UniversityUrumqi 830046 MNR Technology Innovation Center for Central Asia Geo-Information Exploitation and Utilization Urumqi 830046 College of Ecology and Environment Xinjiang UniversityUrumqi 830046

Dust aerosols profoundly influence the radiative balance of the earth–atmosphere system and hence the global and regional *** this study,using multi-source satellite and ground-level observations combined with meteorological data,we investigated the three-dimensional evolution and transport characteristics of aerosols during a dust event that occurred in Xinjiang,China from 19 to 21 March *** of the meteorological data reveals that the dust air mass initially appeared in the northwest of Xinjiang and was subsequently transported to the Hami and Turpan areas due to the prevailing northwesterly winds,after which the direction of the airflow shifted due to topography,and the dust air masses were transported into southern *** air quality in the affected areas decreased rapidly,accompanied by a significant increase in aerosol optical depth (AOD),with the maximum value exceeding 3.5 in some *** addition,the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations(CALIPSO) data reveal that the aerosol particles in the dust-affected areas were mainly dust aerosols,with small amounts of pollutant dust aerosols.A reduction in the attenuated backscatter coefficient (β532||) was found with increasing altitude,with the dust aerosol pollution mainly distributed in the lower *** size of dust particles in the lower troposphere was relatively small and *** depolarization ratio (PDR) values at altitudes of 8–10 km were relatively lower than those recorded in the lower troposphere,whereas the color ratio (CR)values were higher,which may have been influenced by the sparse vegetation coverage and poor subsurface conditions in Xinjiang,and attributable to the fact that regular large particles of dust are more likely to be dispersed to altitudes between 8 and 10 km within a short period of *** a consequence of the meteorological conditions and topography,the dusting process in Xinjiang persisted for a relatively long peri

关键词： dust event CALIPSO atmospheric aerosol vertical distribution Xinjiang Northwest China

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vertical distribution CHARACTERISTICS OF ATMOSPHERIC AEROSOLS IN LIAONING

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Acta meteorologica Sinica 2000年第3期14卷 373-382页

作者：杨军周德平宫福久高建春李子华 NanjingInstitute of Meteorology.Nanjing 210044 Liaoning Rain-Making Office.Shenyang 110015 Beijing Research Institute of Applied Meteorology.Beijing 100025 Nanjing Institute of Meteorology Nanjing 210044

16 aircraft missions were conducted for the measurement of atmospheric aerosols in separate days of late spring and early summer of 1996 and *** paper deals with detailed analysis of the variation in vertical/horizontal distributions of the concentration of the particles and their size distribution at 0—5 km above ground,and with the relations to temperature and relative humidity documented in *** suggests that the concentrations show different distribution features in vertical above and below the cap of the mixed layer:the particle size distribution is subject to a range of forming mechanisms,displaying a multi-modal pattern:the horizontal concentration experiences remarkable variation:temperature and relative humidity stratifications have conspicuous influence on the concentration and size distribution of aerosols.

关键词： atmospheric aerosol vertical distribution size distribution aircraft sounding

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