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141篇 您的检索式:作者名="SUN XiaoMin"
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1Spatiotemporal variation in alpine grassland phenology in the Qinghai-Tibetan Plateau from 1999 to 2009显示文摘Plant phenology is the most salient and sensitive indicator of terrestrial ecosystem response to climate change.Studying its change is significantly important in understanding and predicting impressively changes in terrestrial ecosystem.Based on NDVI from SPOT VGT,this paper analyzed the spatiotemporal changes in alpine grassland phenology in Qinghai-Tibetan Plateau from 1999 to 2009.The results are enumerated as follows:(1) The spatial distribution of the average alpine grassland phenology from 1999 to 2009 is closely related to water and heat conditions.Accompanying the deterioration in heat and water conditions from southeast to northwest,the start of growth season(SOG) was delayed gradually,the end of growth season(EOG) advanced slowly,and the length of growth season(LOG) shortened gradually.Elevation played an important role in the regional differentiation of phenology,but a dividing line of approximately 3500 m existed.Below this line,the phenology fluctuated irregularly with altitude change,whereas above the line,the phenology is closely related to altitude change.(2) From 1999 to 2009,SOG of the alpine grassland came earlier by six days per decade(R2=0.281,P=0.093),EOG was late by two days per decade(R2=0.031,P=0.605),and LOG lengthened by eight days per decade(R2=0.479,P=0.018).The early SOG,the late EOG,and the extended LOG mainly occurred at the center and east of the Plateau.SOG in most of the Plateau advanced significantly,especially in the eastern Plateau.(3) The inter-annual phenology changes of the alpine grassland in the Qinghai-Tibetan Plateau exhibited significant differentiation at different elevation and natural zones.The inter-annual changes at high altitude were more complicated than that at low altitude.The most significant phenology changes were found in the eastern Qinghai-Qilian montane steppe zone,and non-significant changes occurred in the Southern Tibet montane shrub-steppe zone.DING MingJun ZHANG YiLi SUN XiaoMin LIU LinShan WANG ZhaoFeng BAI WanQi 2013Chinese Science Bulletin2013,58,3:44
2Characteristics of δ^(18)O in precipitation over Eastern Monsoon China and the water vapor sources显示文摘Monsoon circulation is an important carrier of water vapor transport, and it impacts the precipitation of the monsoonal regions through the constraints and controls of large-scale water vapor transport and distributions as well as the water vapor balance. An overall research on stable Hydrogen and Oxygen isotopes in precipitation over Eastern Monsoon China could benefit a comprehensive understanding of the monsoonal precipitation mechanism. Seventeen field stations of the Chinese Network of Isotopes in Precipitation (CHNIP) have been selected to collect monthly composite precipitation samples during the years 2005―2006. Components of δ D and δ 18O have been analyzed to achieve the spatiotemporal distributions. The established Local Meteoric Water Line δ D=7.46δ 18O+0.90 based on the 274 obtained monthly samples could be treated as isotope input functions across the region, due to basically reflecting the specific regional meteorological conditions over Eastern Monsoon China. The δ-value depleted from coastal to inner area. In Southern China and Northeastern China there were typical periodic patterns of δ18O. Different dominant affecting metrological factors have been raised with different regions. From south to north, the temperature effect of δ18O enhanced, while the amount effect changed from existing at an all-year-scale in Southern China to being only remarkable during the main rainy seasons in North China and Northeastern China. Main geographical controls varied from altitude in Southern China and North China to latitude in Northeastern China. Furthermore, δ18O had an implication of advance and retreat of the monsoon as well as rainfall belt transfer. δ 18O was also a tracer for the movement path of typhoon and tropical storms.LIU JianRong SONG XianFang YUAN GuoFu SUN XiaoMin LIU Xin 2010Chinese Science Bulletin2010,55,2:40
3Start of vegetation growing season on the Tibetan Plateau inferred from multiple methods based on GIMMS and SPOT NDVI data显示文摘在这研究,我们使用了四个方法从 1982~2012 在西藏的高原( TP )上调查成长季节( SGS )的开始,用从全球库存为研究建模并且印射获得的规范的差别植被索引( NDVI )数据( GIMSS , 19822006 )并且点植被( SPOT-VGT , 19992012 )。用四个方法估计的 SGS 价值沿着纬度或高度的坡度显示出类似的空间模式,但是与在 SGS 日期的重要变化。最大的差异主要在这些区域被发现与最高或最低植被范围。在 1982 和 1998 之间,然而,从四个方法导出的 SGS 值都根据更最近的点 VGT 数据(19992012 ) 显示一个进展趋势,没有 TP 上的 SGS 的连续地进展的趋势。在价值从在 1999 和 2006 之间的 GIMMS 和点导出的 SGS 之间的关联的分析数据来源与问候在趋势表明一致性到并且到使用的四个分析方法。与另外的方法相比,最大的一致性在之间在里面 situ 数据和检索的 SGS 值与方法 3 被获得(NDVI 比率的阀值) 。避免错误在有多样的植被类型和物理环境的一个广阔区域,知道不同植被类型的季节的变化特征是批评的,特别地在有稀少的草地的区域或常绿树森林。DING Mingjun LI Lanhui ZHANG Yili SUN Xiaomin LIU Linshan GAO Jungang WANG Zhaofeng LI Yingnian 2015Journal of Geographical Sciences2015,25,2:17
4Advances in carbon flux observation and research in Asia显示文摘As an important component of FLUXNET, Asia is increasingly becoming the hotspot in global carbon research for its vast territory, complex climate type and vegetation diversity. The present three regional flux observation networks in Asia (i.e. AsiaFlux, KoFlux and ChinaFLUX)have 54 flux observation sites altogether, covering tropic rainforest, evergreen broad-leaved forest, broad-leaved and coniferous mixed forest, shrubland, grassland, alpine meadow and cropland ecosystems with a latitudinal distribution from 2°N to 63°N. Long-term and continuous fluxes of carbon dioxide, water vapor and energy between the biosphere and atmosphere are mainly measured with eddy covariance technique to (1) quantify and compare the carbon, water and energy budgets across diverse ecosystems; (2) quantify the environmental and biotic controlling mechanism on ecosystem carbon, water and energy fluxes; (3) validate the soil-vegetation-atmosphere model; and (4) serve the integrated study of terrestrial ecosystem carbon and water cycle. Over the last decades, great advancements have been made in the theory and technology of flux measurement, ecosystem flux patterns, simulation and scale conversion by Asian flux community. The establishment of ChinaFLUX has greatly filled the gap of flux observation and research in Eurasia. To further promote the flux measurement and research,accelerate data sharing and improve the data quality, it is necessary to present a methodological system of flux estimation and evaluation over complex terrain and to develop the integrated research that combines the flux measurement, stable isotope measurement, remote sensing observation and GIS technique. It also requires the establishment of the Joint Committee of Asian Flux Network in the Asia-Pacific region in order to promote the cooperation and communication of ideas and data by supporting project scientists, workshops and visiting scientists.YU Guirui, ZHANG Leiming, SUN Xiaomin, FU Yuling & LI Zhengquan Synthesis Center of Chinese Ecosystem Research Network (CERN), 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 2005Science China Earth Sciences2005,48,z1:16
5An operational two-layer remote sensing model to estimate surface flux in regional scale: Physical background显示文摘Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of mixed pixel in four extreme points in combination with the measurements of dry and wet points in calibration fields and improved the reliability of positioning dry and wet line. A new two-layer energy-separation algorithm was proposed,which was simple and direct without resistance network parameters for each pixel. We also proposed a new thought about the effect of advection. The albedo of mixed pixel was also separated with PCACA. In combination with two-layer energy-separation algorithm, the net radiation of mixed pixel was separated to overcome the uncertainty of conventional energy-separation algorithm using Beer's Law. Through the validation of retrieval result, this method is proved to be feasible and operational. At the same time, the uncertainty of this algorithm was objectively analyzed.ZHANG Renhua SUN Xiaomin WANG Weimin XU Jinping ZHU Zhilin TIAN Jing 2005Science China Earth Sciences2005,48,z1:16
6Meteorological control on CO_2 flux above broad-leaved Korean pine mixed forest in Changbai Mountains显示文摘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 measurements.The 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.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 2005Science China Earth Sciences2005,48,z1:15
7Stable isotopes of summer monsoonal precipitation in southern China and the moisture sources evidence from δ^18O signature显示文摘Summer monsoons (South Asian monsoon,South China Sea monsoon and Sub-tropical monsoon) are prominent features of summertime climate over southern China. Dif-ferent monsoons carry different inflow moisture into China and control the temporal and spa-tial distributions of precipitation. Analyses of meteorological data,particularly wind,tempera-ture and pressure anomalies are traditional methods of characterizing moisture sources and transport patterns. Here,we try to utilize the evidence from stable isotopes signatures to trace summer monsoons over southern China. Based on seven CHNIP (Chinese Network of Iso-topes in Precipitation) observatory stations located in southern China,monthly composite precipitation samples have been collected and analyzed for the composition of δ18O during July,2005. The results indicated that the spatial distributions of δ18O in precipitation could properly portray the moisture sources together with their transport pathways. Moreover,the amount effect,altitude effect,temperature effect and the correlation between δ18O vs. relative humidity were discussed.LIU Jianrong SONG Xianfang YUAN Guofu SUN Xiaomin LIU Xin WANG Zhimin WANG Shiqin 2008Journal of Geographical Sciences2008,18,2:15
8Relative humidity reconstruction for northwestern China's Altay Mountains using tree-ring δ^(18)O显示文摘Relative humidity is an important factor in water and water vapor feedback cycles.In this study,we established a 222-year annual tree-ring δ^(18)O chronology for Siberian larch(Larix sibirica Ldb.)from the Altay Mountains in northwestern China.Climate response analyses revealed that the relative humidity was the primary factor limiting tree-ring δ^(18)O fractionation.Based on our analysis,tree-ring δ^(18)O can be used to reconstruct the July–August relative humidity based on both a reasonable mechanism of tree-ring δ^(18)O fractionation and a statistically significant regression model.We used this model to reconstruct variations in the July–August relative humidity,and the model explained 47.4% of the total variation in the measured relative humidity data from 1961 to 2011.The relative humidity in the study area increased from 1900 to the 1990s and decreased thereafter.Two regime-shift dry periods were detected during the study period(one from 1817 to 1830 and the other from 2004 to 2011).Guobao Xu Xiaohong Liu Dahe Qin Tuo Chen Wenzhi Wang Guoju Wu Weizhen Sun Wenling An Xiaomin Zeng 2014Chinese Science Bulletin2014,59,2:14
9Turbulence flux measurement above the overstory of a subtropical Pinus plantation over the hilly region in southeastern China显示文摘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 studied site, which was comparable to the 10%-30% of energy imbalance reported in the literature. However, the energy balance closure could be only used as a useful reference criterion.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 2005Science China Earth Sciences2005,48,z1:14
10Moisture variations over the past millennium characterized by Qaidam Basin tree-ring δ^(18)O显示文摘High-resolution tree-ring δ18O chronologies covering the last millennium,although scarce,are essential in understanding patterns of climatic changes in the northeastern region of the Qinghai-Tibetan Plateau.For this study,a tree-ring δ18O chronology with a temporal resolution of 3-years was developed from the long-lived Qilian juniper(Sabina przewalskii Kom.),extending back in time to AD 991.This long δ18O chronology was significantly correlated with the yearly δ18O in tree rings during the common period from 1800 to 2006,and was an effective proxy for relative humidity during the growing season.A low-frequency moisture pattern signified the occurrence of a slight drought during the Medieval Climate Anomaly,a marked occurrence of a wet period during the Little Ice Age,and a trend in increasing moisture levels,although lower than average,alongside the Twentieth Century warming trend.Comparisons to other hydroclimatic reconstructions indicate that this tree-ring18O chronology serves as a reliable paleo-humidity proxy for the Qaidam Basin as well as documenting details of past humidity levels in the region.WANG WenZhi LIU XiaoHong XU GuoBao SHAO XueMei QIN DaHe SUN WeiZhen AN WenLing ZENG XiaoMin 2013Chinese Science Bulletin2013,58,32:14
11Seasonal variation of CO_2 flux and its environmental factors in evergreen coniferous plantation显示文摘The effects of environmental factors on carbon flux were analyzed, the spatial and temporal variation of carbon flux was studied at the two heights of 23 m and 39 m with the eddy covariance technique, and the carbon budget was evaluated for evergreen coniferous plantation in the red earth hilly area during the year 2003. The results showed that photosynthetically active radiation (PAR) and soil temperature are essential factors strongly affecting the net ecosystem exchange (NEE); in the daytime, the response of NEE to PAR shows a rectangular hyperbola trend, and in the nighttime, the significant correlation was observed between soil temperature and soil respiration which was filtered using friction velocity. This ecosystem appeared as a carbon sink along the whole year of 2003, and the carbon flux showed the obvious seasonal fluctuation and diurnal variability. The seasonal peak of NEE occurred in May and June with the daily sum about 0.61-0.67 mg · CO2 · m-2 · s-1. For the severe drought in the mid-summer, the daily sum was 0.40-0.44 mg · CO2 · m-2 · s-1 in July which was only 2/3 of that in the last two months. For the lasted drought of the year, the nadir of NEE happened in the winder with the daily sum about -0.29 to -0.35 mg · CO2 · m-2 · s-1. The sink intensity of the ecosystem was about -0.553 to -0.645 kg · Cm-2 per year in 2003.LIU Yunfen, SONG Xia, YU Guirui, SUN Xiaomin, WEN Xuefa & CHEN Yongrui Institute of Geographic Sciences and Natural Resources Research, Chinese Academy Sciences, Beijing 100101, China Graduate School of the Chinese Academy of Sciences, Beijing 10039, China 2005Science China Earth Sciences2005,48,z1:13
12Ozone concentrations, flux and potential effect on yield during wheat growth in the NorthwestShandong Plain of China显示文摘Ozone(O3) concentration and flux(Fo) were measured using the eddy covariance technique over a wheat field in the Northwest-Shandong Plain of China. The O3-induced wheat yield loss was estimated by utilizing O3exposure-response models. The results showed that:(1) During the growing season(7 March to 7 June, 2012), the minimum(16.1 ppb V) and maximum(53.3 ppb V)mean O3 concentrations occurred at approximately 6:30 and 16:00, respectively. The mean and maximum of all measured O3 concentrations were 31.3 and 128.4 ppb V, respectively. The variation of O3 concentration was mainly affected by solar radiation and temperature.(2) The mean diurnal variation of deposition velocity(V d) can be divided into four phases, and the maximum occurred at noon(12:00). Averaged V d during daytime(6:00–18:00) and nighttime(18:00–6:00) were 0.42 and 0.14 cm/sec, respectively. The maximum of measured V d was about1.5 cm/sec. The magnitude of V d was influenced by the wheat growing stage, and its variation was significantly correlated with both global radiation and friction velocity.(3) The maximum mean F o appeared at 14:00, and the maximum measured F o was-33.5 nmol/(m2·sec). Averaged F o during daytime and nighttime were-6.9 and-1.5 nmol/(m2·sec), respectively.(4) Using O3 exposure-response functions obtained from the USA, Europe, and China, the O3-induced wheat yield reduction in the district was estimated as 12.9% on average(5.5%–23.3%). Large uncertainties were related to the statistical methods and environmental conditions involved in deriving the exposure-response functions.Zhilin Zhu Xiaomin Sun Fenghua Zhao Franz X.Meixner 2015Journal of Environmental Sciences2015,27,8:12
13Spatio-temporal variation of photosynthetically active radiation in China in recent 50 years显示文摘在中国上基于 weather/ecological 车站的长期的测量数据,计算并且生产每年平均、平均 seasonally 的光合地活跃的放射(同等) 的这份报纸从 1961 ~ 2007 的空间数据,用 climatological 计算和 spatialization 技术。在中国在上的每年平均、平均 seasonally 的同等空间数据的时间空间的变化特征最近 50 年与 Mann-Kendall 趋势分析方法和 GIS 被分析空间分析技术。结果显示出那:(1 ) 总体上,同等的空间分发越过中国复杂、不同类,与在中国的东方、南部的部分的更低的同等和在西方的部分的更高的同等。在中国上的吝啬的年度同等从 17.7 摩尔 m ? 2 d ? 1 ~ 39.5 摩尔 m ? 2 d ? 1。(2 ) 在中国上的每个象素的每年平均、平均 seasonally 的同等总体上被平均,平均数与变动进程显然珍视衰落,并且每年平均的同等的变化的率是 ? 0.138 摩尔 m ? 2 d ? 1/10a。在四个季节之中的变化振幅是不同的,与在里面的最大的落下夏天,和同等的下降速度在 1990 年代,速度在以后慢下来前是更快的。(3 ) 由每个象素的分析证明那同等显著地衰退(=0.05 ) 在中国的大多数部分。夏天和冬季在同等的 interannual 可变性起更重要的作用。诺思中国总是是在四个季节的一个减少的地区,当 Qinghai 西藏高原的西北转弯是在四个季节的一个增加的地区时。(4 ) 同等的 interannual 可变性的空间分布在不同时期之中变化。在某个区域的同等的 interannual 可变性不仅在四个季节之中,而且在不同时期之中是不同的。ZHU Xudong HE Honglin LIU Min YU Guirui SUN Xiaomin GAO Yanhua 2010Journal of Geographical Sciences2010,20,6:12
14The Limiting Effect of Deep Soil Water on Evapotranspiration of a Subtropical Coniferous Plantation Subjected to Seasonal Drought显示文摘Seasonal drought is a common occurrence in humid climates. The year 2003 was the driest year during the period 1985– 2011 in southeastern China. The objective of this study was to elucidate the impact of the exceptional drought in 2003, compared with eddy flux measurements during 2004–11, on the dynamics of evapotranspiration(ET) and related factors, as well as their underlying mechanisms, in a subtropical coniferous plantation in southeastern China. It was found that daily ET decreased from 5.34 to 1.84 mm during the intensive drought period and recovered to 4.80 mm during the subsquent recovering drought period. Path analysis indicated that ET was mainly determined by canopy conductance and deep soil water content(50 cm) during the intensive drought and recovering drought periods, respectively. The canopy conductance offset the positive effect of air vapor pressure deficit on ET when suffering drought stress, while the canopy conductance enhanced the positive effect of air temperature on ET during the late growing season. Because the fine roots of this plantation are mainly distributed in shallow soil, and the soil water in the upper 40 cm did not satisfy the demand for ET, stomatal closure and defoliation were evident as physiological responses to drought stress.TANG Yakun WEN Xuefa SUN Xiaomin ZHANG Xinyu WANG Huimin 2014Advances in Atmospheric Sciences2014,31,2:11
15Major advances in studies of the physical geography and living environment of China during the past 70 years and future prospects显示文摘The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.Fahu CHEN Bojie FU Jun XIA Duo WU Shaohong WU Yili ZHANG Hang SUN Yu LIU Xiaomin FANG Boqiang QIN Xin LI Tingjun ZHANG Baoyuan LIU Zhibao DONG Shugui HOU Lide TIAN Baiqing XU Guanghui DONG Jingyun ZHENG Wei YANG Xin WANG Zaijun LI Fei Wang Zhenbo HU Jie WANG Jianbao LIU Jianhui CHEN Wei HUANG Juzhi HOU Qiufang CAI Hao LONG Ming JIANG Yaxian HU Xiaoming FENG Xingguo MO Xiaoyan YANG Dongju ZHANG Xiuhong WANG Yunhe YIN Xiaochen LIU 2019Science China Earth Sciences2019,62,11:11
16Correcting method of eddy covariance fluxes over non-flat surfaces and its application in ChinaFLUX显示文摘Although Eddy Covariance (EC) technique is one of the best methods for estimating the energy and mass exchanges between underlying surface and atmosphere in micrometeorology, errors and uncertainties still exist without necessary corrections. In this paper, we will focus on the effect of coordinate system on the eddy fluxes. Based on the data observed over four sites (one farmland site, one grassland site and two forest sites), the effects of three coordinate system transforming methods (Double Rotation-DR, Triple Rotation-TR and Planar Fit-PF)on the turbulent fluxes are analyzed. It shows that (i) the corrected fluxes are more or less than the uncorrected fluxes, which is related mainly to the sloping degree of surface, wind speed and wind direction; and (ii) pitch angle has a sinusoidal dependence on wind direction, especially in the regular sloping terrain; and (iii) PF method is something like the simplification of TR or DR,and there are not obvious distinctions in correction in sloping grassland and flat farmland, but PF method is not suitable for uneven and irregular forest sites.ZHU Zhilin, SUN Xiaomin, ZHOU Yanlian, XU Jinping, YUAN Guofu & ZHANG Renhua 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 2005Science China Earth Sciences2005,48,z1:10
17Internet of Things to network smart devices for ecosystem monitoring显示文摘Smart, real-time, low-cost, and distributed ecosystem monitoring is essential for understanding and managing rapidly changing ecosystems. However, new techniques in the big data era have rarely been introduced into operational ecosystem monitoring, particularly for fragile ecosystems in remote areas.We introduce the Internet of Things(IoT) techniques to establish a prototype ecosystem monitoring system by developing innovative smart devices and using IoT technologies for ecosystem monitoring in isolated environments. The developed smart devices include four categories: large-scale and nonintrusive instruments to measure evapotranspiration and soil moisture, in situ observing systems for CO2 and d13 C associated with soil respiration, portable and distributed devices for monitoring vegetation variables, and Bi-CMOS cameras and pressure trigger sensors for terrestrial vertebrate monitoring. These new devices outperform conventional devices and are connected to each other via wireless communication networks. The breakthroughs in the ecosystem monitoring IoT include new data loggers and longdistance wireless sensor network technology that supports the rapid transmission of data from devices to wireless networks. The applicability of this ecosystem monitoring IoT is verified in three fragile ecosystems, including a karst rocky desertification area, the National Park for Amur Tigers, and the oasis-desert ecotone in China. By integrating these devices and technologies with an ecosystem monitoring information system, a seamless data acquisition, transmission, processing, and application IoT is created. The establishment of this ecosystem monitoring IoT will serve as a new paradigm for ecosystem monitoring and therefore provide a platform for ecosystem management and decision making in the era of big data.Xin Li Ning Zhao Rui Jin Shaomin Liu Xiaomin Sun Xuefa Wen Dongxiu Wu Yan Zhou Jianwen Guo Shiping Chen Ziwei Xu Mingguo Ma Tianming Wang Yonghua Qu Xinwei Wang Fangming Wu Yuke Zhou 2019Science Bulletin2019,64,17:10
18Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China,2004-2010显示文摘The nitrate-nitrogen(NO 3-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations,representing typical agroand forest ecosystems,were assessed using monitoring data collected between 2004 and 2010.Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater,and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made.Results indicated that most of the NO 3--N concentrations in groundwater from the agroand forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard:Quality Standard for Ground Water(≤ 20 mg/L).Over the study period,the average NO 3--N concentrations were significantly higher in agro-ecosystems(4.1 ± 0.33 mg/L) than in forest ecosystems(0.5 ± 0.04 mg/L).NO 3-N concentrations were relatively higher(> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems.These elevated concentrations occurred mainly in the Ansai,Yucheng,Linze,Fukang,Akesu,and Cele field sites,which were located in arid and semiarid areas where irrigation rates are high.We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.Xinyu Zhang Zhiwei Xu Xiaomin Sun Wenyi Dong Deborah Ballantine 2013Journal of Environmental Sciences2013,25,5:10
19Short-term variations of vapor isotope ratios re- veal the influence of atmospheric processes显示文摘大气的水蒸汽的稳定的同位素在空气在水运动和阶段变化上揭示富有的信息。这里,我们介绍了 D 的二将近连续的时间系列和测量在的大气的水蒸汽(v ) 的 18O 时时,在表面的间隔在在原处使用测量的 Shijiazhuang 在北京并且在一顶冬季小麦华盖上面通风技术。在降水事件期间,在北京和 Shijiazhuang 的 v 价值处于有降水水的平衡的状态,揭示降水过程的影响。然而,来自平衡状态的 v 离开断然与本地相对湿度被相关。注意 v 趋于在北京充实,但是在降水事件期间在 Shijiazhuang 弄空,它主要源于在 Shijiazhuang 充实 v 的蒸发过程的影响。在季节的时间规模上, v 值是在北京和 Shijiazhuang 混合比率的水蒸汽的木头线性的函数。混合比率的水蒸汽是由瑞利蒸馏机制的 v 的一个优秀预言者,显示空气团移流能也起在决定 v 的一个重要作用。在上一日报时间规模, v 与边界层乘火车的大气的过程有关仔细在是的北京在早下午小时到达了最小。在种冬季小麦的季节的山峰期间,然而, v 在清早到达了最小,并且整个白天逐渐地增加了,并且在迟了的下午到达了最大值,它由在边界层乘火车和本地大气的过程之间的相互作用是负责的,例如蒸发和露水形成。这研究在决定表面 v 为植被的重要角色有含意并且加亮需要进行 v 测量在上短期(例如日报) 时间规模。ZHANG Shichun SUN Xiaomin WANG Jianlin YU Guirui WEN Xuefa 2011Journal of Geographical Sciences2011,21,3:10
20Eddy flux corrections for CO_2 exchange in broad-leaved Korean pine mixed forest of Changbai Mountains显示文摘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.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 2005Science China Earth Sciences2005,48,z1:8
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