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Turbulence flux measurement above the overstory of a subtropical Pinus plantation over the hilly region in southeastern china

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Science china Earth sciences 2005年第Z1期48卷 63-73页

作者： 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 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 chinese Ecosystem research Network Synthesis research Center Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

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 stu

关键词： eddy covariance, power spectra, cospectra, Monin-Obukhov similarity, energy balance closure, nocturnal turbulence flux.

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Photosynthesis-transpiration coupling model at canopy scale in terrestrial ecosystem

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Science china Earth sciences 2005年第Z1期48卷 160-171页

作者： REN Chuanyou, YU Guirui, WANG Qiufeng & GUAN Dexin institute of geographic sciences and natural resources research, chinese academy of sciences, beijing 100101, china Shenyang Agricultural University, Shenyang 110161, china institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Graduate School of the chinese academy of sciences, beijing 100039, china institute of geographic sciences and natural resources research Chinese Academy of Sciences Beijing 100101 China Shenyang Agricultural University Shenyang 110161 China Graduate School of the chinese academy of sciences Beijing 100039 China institute of geographic sciences and natural resources research Chinese Academy of Sciences Beijing 100101 China 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 institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China

At the hypothesis of big leaf, an ecosystem photosynthesis-transpiration coupling cycle model was established by the scaled SMPT-SB model from single leaf to canopy, and model parameterization methods were discussed. Through simulating the canopy light distribution, canopy internal conductance to CO2 can be scaled from single leaf to canopy by integrating to canopy using the relationship between single internal conductance and photosynthetic photon flux density. Using the data observed by eddy covariance method from the Changbai Mountains site of chinaFLUX, the application of the model at the canopy scale was examined. Under no water stress, the simulated net ecosystem photosynthesis rate fitted with the observed data very well, the slope and R2 of the line regression equation of the observed and simulated values were 0.7977 and 0.8892, respectively (n = 752), and average absolute error was 3.78 μmol CO2 m-2s-1; the slope, R2 and average absolute error of transpiration rate were 0.7314, 0.4355 and 1.60mmol H2O m-2 s-1, respectively (n = 752). The relationship between canopy photosynthesis,transpiration and external environmental conditions was discussed by treating the canopy as a whole and neglecting the comprehensive feedback mechanism within canopy, and it was noted that the precipitation course affected the transpiration rate simulation badly. Compared to the models based on eco-physiological processes, the SMPT-SB model was simple and easy to be used. And it can be used as a basic carbon and water coupling model of soil-plant-atmosphere continuum.

关键词： photosynthesis rate, transpiration rate, SMPT-SB model, internal conductance, canopy scale.

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Differential Hydrological Grey Model (DHGM) with self-memory function and its application to flood forecasting

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Science china(Technological sciences) 2009年第4期52卷 1039-1049页

作者： CHEN XiangDong1, XIA Jun1,2 & XU Qian3 1 Key Laboratory of Water Cycle and Related Land Surface Processes, institute of geographic sciences and natural resources research, chinese academy of sciences, beijing 100101, china 2 State Key Laboratory of Water resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, china 3 School of Hydrology and Water resources, Hohai University, Nanjing 210098, china 1. Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 2. State Key Laboratory of Water resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China 3. School of Hydrology and Water resources Hohai University Nanjing 210098 China

This paper addresses a problem of flood forecasting with the self-memory function. Considering flood forecasting’s uncertainty and updating demand, a hybrid hydrological model, namely Differential Hy- drological Grey Model with self-memory function (DHGM-SM), is developed. The model has two fold features. One is to establish a self-memorization equation linked with DHGM, that could extract useful information from past data series and realize updating of hydrological dynamic process. The other is that this model has higher efficiency relative to original hydrological model without self-memory func- tion. This approach was applied to river flow forecasting of two representative basins in Tunxi of South china and Daqinggou of North china. It is shown that this hybrid method has satisfactory forecasting accuracy by examination of both calibration and validation.

关键词： differential grey model the self-memorization principle real-time forecasting faded-memory recursive least square method

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Net ecosystem CO_2 exchange and controlling factors in a steppe——Kobresia meadow on the Tibetan Plateau

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Science china Earth sciences 2006年第S2期49卷 207-218页

作者： SHI Peili, SUN Xiaomin, XU Lingling, ZHANG Xianzhou, HE Yongtao, ZHANG Dongqiu & YU Guirui institute of geographic sciences and natural resources research, chinese academy of sciences, beijing 100101, china Graduate University of chinese academy of sciences, beijing 100039, china 1. institute of geographic sciences and natural resources research Chinese Academy of Sciences Beijing 100101 China 2. Graduate University of chinese academy of sciences Beijing 100039 China

Knowledge of seasonal variation of net ecosystem CO2 exchange (NEE) and its biotic and abiotic controllers will further our understanding of carbon cycling process, mechanism and large-scale modelling. Eddy covariance technique was used to measure NEE, biotic and abiotic factors for nearly 3 years in the hinterland alpine steppe--Korbresia meadow grassland on the Tibetan Plateau, the present highest fluxnet station in the world. The main objectives are to investigate dynamics of NEE and its components and to determine the major controlling factors. Maximum carbon assimilation took place in August and maximum carbon loss occurred in November. In June, rainfall amount due to monsoon climate played a great role in grass greening and consequently influenced interannual variation of ecosystem carbon gain. From July through September, monthly NEE presented net carbon assimilation. In other months, ecosystem exhibited carbon loss. In growing season, daytime NEE was mainly controlled by photosynthetically active radiation (PAR). In addition, leaf area index (LAI) interacted with PAR and together modulated NEE rates. Ecosystem respiration was controlled mainly by soil temperature and simultaneously by soil moisture. Q10 was negatively correlated with soil temperature but positively correlated with soil moisture. Large daily range of air temperature is not necessary to enhance carbon gain. Standard respiration rate at referenced 10℃(R10) was positively correlated with soil moisture, soil temperature, LAI and aboveground biomass. Rainfall patterns in growing season markedly influenced soil moisture and therefore soil moisture controlled seasonal change of ecosystem respiration. Pulse rainfall in the beginning and at the end of growing season induced great ecosystem respiration and consequently a great amount of carbon was lost. Short growing season and relative low temperature restrained alpine grass vegetation development. The results suggested that LAI be usually in a low le

关键词： Tibetan Plateau alpine steppe--Kobresia meadow NEE ecosystem respiration PAR soil moisture temperature response LAI eddy covariance.

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Seasonal variation in carbon exchange and its ecological analysis over Leymus chinensis steppe in Inner Mongolia

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Science china Earth sciences 2006年第S2期49卷 186-195页

作者： HAO Yanbin, WANG Yanfen, SUN Xiaomin, HUANG Xiangzhong, CUI Xiaoyong, NIU Haishan, ZHANG Yahong & YU Guirui Laboratory of Quantitative Vegetation Ecology, institute of Botany, chinese academy of sciences, beijing 100093, china Department of Biology, Graduate University of the chinese academy of sciences, beijing 100049, china Ningxia University, Yinchuan 750001, china institute of geographic sciences and natural resources research, chinese academy of sciences, beijing 100101, china 1. Laboratory of Quantitative Vegetation Ecology Institute of Botany Chinese Academy of Sciences Beijing 100093 China 2. Department of Biology Graduate University of the Chinese Academy of Sciences Beijing 100049 China 4. institute of geographic sciences and natural resources research Chinese Academy of Sciences Beijing 100101 China 3. Ningxia University Yinchuan 750001 China

Eddy covariance technique was used to measure carbon flux during two growing seasons in 2003 and 2004 over typical steppe in the Inner Mongolia Plateau, china. The results showed that there were two different CO2 flux diurnal patterns at the grassland ecosystem. One had a dual peak in diurnal course of CO2 fluxes with a depression of CO2 flux after noon, and the other had a single peak. In 2003, the maximum diurnal uptake and emitting value of CO2 were -7.4 and 5.4 g·m-2·d-1 respectively and both occurred in July. While in 2004, the maximum diurnal uptake and release of CO2 were -12.8 and 5.8 g·m-2·d-1 and occurred both in August. The grassland fixed 294.66 and 467.46 g CO2·m-2 in 2003 and 2004, and released 333.14 and 437.17 g CO2·m-2 in 2003 and 2004, respectively from May to September. Water availability and photosynthetic active radiation (PAR) are two important factors of controlling CO2 flux. Consecutive precipitation can cause reduction in the ability of ecosystem carbon exchange. Under favorable soil water conditions, daytime CO2 flux is dependent on PAR. CO2 flux, under soil water stress conditions, is obviously less than those under favorable soil water conditions, and there is a light saturation phenomena at PAR=1200μmol·m-2·s-1. Soil respiration was temperature dependent when there was no soil water stress; otherwise, this response became accumulatively decoupled from soil temperature.

关键词： Leymus chlnensls CO2 flux photosynthetic active radiation light saturation phenomena eddy covariance technique.

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Photosynthetic characteristics of dominant tree species and canopy in the broadleaved Korean pine forest of Changbai Mountains

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Science china Earth sciences 2006年第S2期49卷 89-98页

作者： WU Jiabing, GUAN Dexin, SUN Xiaomin, ZHANG Mi, SHI Tingting, HAN Shijie & JIN Changjie institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Graduate University of the chinese academy of sciences, beijing 100049, china institute of geographic sciences and natural resources research, chinese academy of sciences, beijing 100101, china

Based on the light-photosynthesis response measurement at leaf level, combined with over- and under-canopy eddy covariance measurements, research on photosynthetic characteristics of single trees and forest canopy was conducted. The relationship between light intensity and photo-synthetic rates for leaves and canopy can be well fitted by a non-rectangular hyperbola model. Mongolian oak presented a high light compensation point, Lcp (28μmol·m-2·s-1), a light saturation point Lsp (>1800μmol·m-2·s-1), and a maximal net photosynthetic rate Pmax (9.96μmol·m-2·s-1), which suggest that it is a typical heliophilous plant. Mono maple presented the highest apparent quantum efficiencyα(0.066) but the lowest, Lcp (16μmol·m-2·s-1), Lsp (=800μmol·m-2·s-1), and Pmax (4.51μmol·m-2·s-1), which suggest that it is heliophilous plant. Korean pine showed the lowestαvalue but a higher Pmax, which suggest that it is a semi-heliophilous plant. At the canopy level, the values of both or and Pmax approached the upper limit of reported values in temperate forests, while Lcp was within the lower limit. Canopy photosynthetic characteristics were well consistent with those of leaves. Both showed a high ability to photosynthesize. However, environmental stresses, especially high vapor pressure deficits, could significantly reduce the photosynthetic ability of leaves and canopy.

关键词： photosynthesis light response curve broadleaved Korean pine forest eddy covariance method.

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Eddy flux corrections for CO_2 exchange in broad-leaved Korean pine mixed forest of Changbai Mountains

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Science china Earth sciences 2005年第Z1期48卷 106-115页

作者： WU Jiabing, GUAN Dexin, SUN Xiaomin, YU Guirui, ZHAO Xiaosong, HAN Shijie & JIN Changjie institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Graduate school of the chinese academy of sciences, beijing 100093, china 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 100093 China institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China institute of geographic sciences and natural resources research Chinese Academy of Sciences Beijing 100101 China

Based on analysis of mechanisms causing energy no-closure and nocturnal low fluxes issues for CO2 exchange studies by eddy covariance method, corrections were done with the raw data sets obtained from Changbai Mountains forest flux site, to evaluate the impacts of sonic anemometer tilt, frequency response limitations and advection on estimation of CO2 exchange, respectively. The results show that the planar fit coordinate transforming method is superior to the streamline coordinate transforming method in tilt correction. The latter could cause a systematical underestimation of eddy fluxes relating with the angle of sensor and terrain tilt. The underestimation of CO2 and energy fluxes for frequency response limitations average 3.0% and 2.0% during daytime, respectively, which increase by 9.0% and 5.5% during nighttime, respectively. The corrections of frequency response limitations are closely related to atmospheric stability. The advection loss of CO2 fluxes is dominated by nocturnal vertical advection, which is at least 18% when the horizontal advection is neglected. It is suggested that more work be done to understand the characteristics of horizontal advection and turbulent eddies under a complexcircumstance.

关键词： eddy covariance method, carbon cycle, flux correction, CO2 exchange, tilt correction.

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Meteorological control on CO_2 flux above broad-leaved Korean pine mixed forest in Changbai Mountains

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Science china Earth sciences 2005年第Z1期48卷 116-122页

作者： GUAN Dexin, WU Jiabing, YU Guirui, SUN Xiaomin, ZHAO Xiaosong, HAN Shijie & JIN Changjie institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china 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 institute of geographic sciences and natural resources research Chinese Academy of Sciences Beijing 100101 China

The impacts of temperature, photosynthetic active radiation (PAR) and vapor pressure deficit (VPD) on CO2 flux above broad-leaved Korean pine mixed forest in the Changbai Mountains were studied based on eddy covariance and meteorological factors *** results showed that, daytime CO2 flux was mainly controlled by PAR and they fit Michaelis-Menten equation. Meanwhile VPD also had an influence on the daytime flux. Drier air reduced the CO2 assimilation of the ecosystem, the drier the air, the more the reduction of the assimilation. And the forest was more sensitive to VPD in June than that in July and August. The respiration of the ecosystem was mainly controlled by soil temperature and they fit exponential equation. It was found that this relationship was also correlated with seasons; respiration from April to July was higher than that from August to November under the same temperature. Daily net carbon exchange of the ecosystem and the daily mean air temperature fit exponential equation. It was also found that seasonal trend of net carbon exchange was the result of comprehensive impacts of temperature and PAR and so on. These resulted in the biggest CO2 uptake in June and those in July and August were next. Annual carbon uptake of the forest ecosystem in 2003 was -184 gC. m-2.

关键词： CO2 flux, soil temperature, PAR, broad-leaved Korean pine mixed forest.

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数字山地垂直带谱研究进展

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山地学报 2008年第1期26卷 12-14页

作者：张百平中国科学院地理科学与资源研究所资源与环境信息系统国家重点实验室北京100101

垂直分带是山地环境研究的基础。近年来我们成功地构了山地垂直带数据模型,可以将我国及全世界山地垂直带谱进行数字集成;归纳出我国31个水平地带、32个垂直地带,奠定了中国山地垂直带谱数字集成的地理学基础。研制了中国山地垂直带谱... 详细信息

垂直分带是山地环境研究的基础。近年来我们成功地构了山地垂直带数据模型,可以将我国及全世界山地垂直带谱进行数字集成;归纳出我国31个水平地带、32个垂直地带,奠定了中国山地垂直带谱数字集成的地理学基础。研制了中国山地垂直带谱信息系统并进行了升级;提出了山地垂直带分布的二次曲线模式,需要今后用更多的数据进一步验证;未来几年的工作包括提高山地垂直带的识别精度,并将山地垂直带谱数字集成工作扩展到欧亚大陆甚至全世界。

关键词：垂直带数字集成地理信息系统

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Peripheral Challenge in Container Port System:A Case Study of Pearl River Delta

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chinese geographical Science 2012年第1期22卷 97-108页

作者： WANG Chengjin WANG Jiao'e Cesar DUCRUET Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China French National Centre for Scientific research UMR 8504 Geographie-citesParis 75006France

The growth of peripheral ports to dominant hubs has been well documented in North America and Europe,and has led to the elaboration of several theoretical ***,although changes in containerization growth have been taking place in the South and East Asia in recent years,particularly in china,only a few studies have fo-cused on this *** Pearl(Zhujiang) River Delta(PRD) has a typical port system with hub and peripheral ports,and provides an excellent case for studying the Peripheral *** paper introduces the theoretical evidence of the Hayuth model and analyzes the evolution of the container port system in the PRD with five phases:1) phase I:preconditions for change and phase II:initial container port development in the 1970s and early 1980s;2) phase III:diffusion,consolidation,and port concentration in the middle and late 1980s;3) phase IV:the load center in the 1990s;and(4) phase V:the Peripheral Challenge since the late *** results illustrate that the Shenzhen port presents mounting challenges to the Hong Kong port,descending from a transshipment hub of china to a regional load center of Southeast ***,this paper explores five points that have led to the evolution of the port system in the PRD:1) competition in the regional port systems;2) different interested parties;3) shift of investment strategies of in-ternational terminal operators;4) integration of shipping networks and reorganization of carriers;and 5) cost-based competition.

关键词： Hayuth model peripheral challenge Pearl River Delta (PRD) container shipping

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