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Flux Footprint Climatology Estimated by Three Analytical Models over a Subtropical Coniferous Plantation in Southeast China

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Journal of Meteorological research 2015年第4期29卷 654-666页

作者：张慧温学发 Jinzhou Ecology and Agriculture Meteorological center Key Laboratory of ecosystem network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Spatial heterogeneity poses a major challenge for the appropriate interpretation of eddy covariance data. The quantification of footprint climatology is fundamental to improving our understanding of carbon budgets, assessing the quality of eddy covariance data, and upscaling the representativeness of a tower flux to regional or global scales. In this study, we elucidated the seasonal variation of flux footprint climatologies and the major factors that influence them using the analytical FSAM （Flux Source Area Model）, KM （Kormann and Meixner, 2001）, and H （Hsieh et al., 2000） models based on eddy covariance measurements at two and three times the canopy height at the Qianyanzhou site of ChinaFLUX in 2003. The differences in footprints among the three models resulted from different underlying theories used to construct the models. A comparison demonstrated that atmospheric stability was the main factor leading to differences among the three models. In neutral and stable conditions,the KM and FSAM values agreed with each other, but they were both lower than the H values. In unstable conditions, the agreement among the three models for rough surfaces was better than that for smooth surfaces, and the models showed greater agreement for a low measurement height than for a high measurement height. The seasonal flux footprint climatologies were asymmetrically distributed around the tower and corresponded well to the prevailing wind direction, which was north-northwest in winter and south-southeast in summer. The average sizes of the 90% flux footprint climatologies were 0.36 0.74 and 1.5-3.2 kin2 at altitudes of two and three times the canopy height, respectively. The average sizes were ranked by season as follows： spring 〉 summer 〉 winter 〉 autumn. The footprint climatology depended more on atmospheric stability on daily scale than on seasonal scale, and it increased with the increasing standard deviation of the lateral wind fluctuations.

关键词： eddy covariance flux footprint flux footprint climatology model comparison

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Prediction of carbon exchanges between China terrestrial ecosystem and atmosphere in 21st century

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Science China Earth Sciences 2008年第6期51卷 885-898页

作者： JI JinJun HUANG Mei LI KeRang chinese ecosystem research network Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.

关键词： carbon cycle AVIM2 climate change B2 scenario China terrestrial ecosystems

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Evapotranspiration of an oasis-desert transition zone in the middle stream of Heihe River, Northwest China

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Journal of Arid Land 2014年第5期6卷 529-539页

作者： LiWen ZHAO WenZhi ZHAO Linze Inland River Basin research Station Chinese Ecosystem Network Research Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences

As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters（e.g. leaf area index（LAI）） of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference（ET0） and actual evapotranspiration（ETc） using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation（Ep） measured by E601 pan evaporator, four aspects were analyzed：（1） ET0 was firstly verified by Ep;（2） Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;（3） Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient（Kp） is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;（4） Crop coefficient（Kc）, an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water（e.g. precipitation and irrigation） of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe

关键词： evapotranspiration pan evaporation water requirement arid region oasis-desert transition zone

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Spatio-temporal variation in transpiration responses of maize plants to vapor pressure deficit under an arid climatic condition

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Journal of Arid Land 2016年第3期8卷 409-421页

作者： ZHAO Wenzhi JI Xibin Linze Inland River Basin research Station Chinese Ecosystem Network Research Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

The transpiration rate of plant is physically controlled by the magnitude of the vapor pressure deficit（VPD） and stomatal conductance. A limited-transpiration trait has been reported for many crop species in different environments, including Maize（Zea mays L.）. This trait results in restricted transpiration rate under high VPD, and can potentially conserve soil water and thus decrease soil water deficit. However, such a restriction on transpiration rate has never been explored in maize under arid climatic conditions in northwestern China. The objective of this study was to examine the transpiration rate of field-grown maize under well-watered conditions in an arid area at both leaf and whole plant levels, and therefore to investigate how transpiration rate responding to the ambient VPD at different spatial and temporal scales. The transpiration rates of maize at leaf and plant scales were measured independently using a gas exchange system and sapflow instrument, respectively. Results showed significant variations in transpiration responses of maize to VPD among different spatio-temporal scales. A two-phase transpiration response was observed at leaf level with a threshold of 3.5 k Pa while at the whole plant level, the daytime transpiration rate was positively associated with VPD across all measurement data, as was nighttime transpiration response to VPD at both leaf and whole plant level, which showed no definable threshold vapor pressure deficit, above which transpiration rate was restricted. With regard to temporal scale, transpiration was most responsive to VPD at a daily scale, moderately responsive at a half-hourly scale, and least responsive at an instantaneous scale. A similar breakpoint（about 3.0 k Pa） in response of the instantaneous leaf stomatal conductance and hourly canopy bulk conductance to VPD were also observed. At a daily scale, the maximum canopy bulk conductance occurred at a VPD about 1.7 k Pa. Generally, the responsiveness of stomatal conducta

关键词： maize limited transpiration trait gas exchange sap flow stomatal conductance vapor pressure deficit

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Degradation leads to dramatic decrease in topsoil but not subsoil root biomass in an alpine meadow on the Tibetan Plateau, China

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Journal of Arid Land 2020年第5期12卷 806-818页

作者： ZHANG Zhenchao LIU Miao SUN Jian WEI Tianxing synthesis research Centre of chinese ecosystem research network Key Laboratory of Ecosystem Network Observation and ModellingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China Arid Land research center Tottori UniversityTottori 6800001Japan School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China

Understanding the effects of degradation on belowground biomass(BGB)is essential for assessment of carbon budget of the alpine meadow ecosystem on the Tibetan Plateau,*** ecosystem has been undergoing serious degradation owing to climate change and anthropogenic *** study examined the response of the vertical distribution of plant BGB to degradation and explored the underlying mechanisms in an alpine meadow on the Tibetan Plateau.A field survey was conducted in an alpine meadow with seven sequential degrees of degradation in the Zoige Plateau on the Tibetan Plateau during the peak growing season of *** measured aboveground biomass(AGB),BGB,soil water content(SWC),soil bulk density(SBD),soil compaction(SCOM),soil organic carbon(SOC),soil total nitrogen(STN),soil total phosphorus(STP),soil available nitrogen(SAN),and soil available phosphorus(STP)in the 0-30 cm soil *** results show that degradation dramatically decreased the BGB in the 0-10 cm soil layer(BGB0-10)but slightly increased the subsoil *** main reason may be that the physical-chemical properties of surface soil were more sensitive to degradation than those of subsoil,as indicated by the remarked positive associations of the trade-off value of BGB0-10 with SWC,SCOM,SOC,STN,SAN,and STP,as well as the negative correlation between the trade-off value of BGB0-10 and SBD in the soil layer of 0-10 *** addition,an increase in the proportion of forbs with increasing degradation degree directly affected the BGB vertical *** findings suggest that the decrease in the trade-off value of BGB0-10 in response to degradation might be an adaptive strategy for the degradation-induced drought and infertile soil *** study can provide theoretical support for assessing the effects of degradation on the carbon budget and sustainable development in the alpine meadow ecosystem on the Tibetan Plateau as well as other similar ecosystems in the world.

关键词： belowground biomass soil properties plant community structure degradation alpine meadow Tibetan Plateau

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Effects of shrub presence and shrub species on ground beetle assemblages (Carabidae,Curculionidae and Tenebrionidae) in a sandy desert,northwestern China

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Journal of Arid Land 2015年第1期7卷 110-121页

作者： JiLiang LIU WenZhi ZHAO FengRui LI Linze Inland River Basin research Station Chinese Ecosystem Research Network Laboratory of Ecohydrology and Integrated River Basin Science Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Shrub presence has an important effect on the structuring of ground beetles in desert ecosystems. In this study, in order to determine how shrubs and different species influence ground beetle assemblages in a sandy desert scrubland dominated by two different shrub species, namely Calligonum mongolicum and Nitraria sphaerocarpa, we sampled the ground beetles using pitfall traps during spring, summer and autumn in 2012. At the community level, the activity density of the ground beetles was shown to be significantly higher under shrubs than in intershrub bare habitats in spring; but an opposite pattern occurred in autumn, suggesting the presence of sea- son-specific shrub effects on the activity density of the ground beetles. Meanwhile, at the trophic group level, the activity density and species richness of predators were significantly greater under shrubs than in intershrub bare habitats in spring, whereas an opposite trend occurred on the activity density in autumn. N. sphaerocarpa shrubs had a positive effect on the activity density of herbivores in the three seasons, and C. mongolicum shrubs had a positive effect on the activity density of detritivores in spring and autumn. At the species level, more Microdera sp. was captured under shrubs than in intershrub bare habitats in spring. During the same time, we also found that C. mongolicum shrubs had a positive effect on Blaps gobiensis in spring, Carabus sp. in autumn, and Tentyria sp. in spring and autumn, and N. sphaerocarpa shrubs had a positive effect on Cyphogenia chinensis, Sternoplax setosa in spring and summer, and Curculionidae sp. 1 in summer and autumn. The study results suggest that shrub presence, shrub species and season variation are important factors for ground beetle assemblages in this desert ecosystem, but the responses of beetles differed among trophic and taxonomic levels.

关键词： Calligonum mongolicum Nitraria sphaerocarpa ground beetle assemblages sandy desert ecosystem Heihe River basin

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The ecological role of dew in assisting seed germination of the annual desert plant species in a desert environment, northwestern China

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Journal of Arid Land 2016年第2期8卷 264-271页

作者： ZHUANG Yanli ZHAO Wenzhi Linze Inland River Basin research Station Chinese Ecosystem Research Network Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences

It is important to understand the effects of dew events on non-mucilaginous seed germination of annual desert plant species during dry seasons, which is critical to maintaining long-term soil seed banks in a harsh desert environment. We hypothesize that dew deposition also assists in the non-mucilaginous seed germination of annual desert species. A common field dew treatment experiment was conducted in the Linze Inland River Basin research Station to investigate the effects of dew deposition on the seed germination of four annual species, including Agriophyllum squarrosum, Corispermum mongoficum, Bassia dasyphylla and Halogeton arachnoideus. The results showed that the presence of dew significantly increased seed germination percentages and decreased the nonviable seed percentages of B. dasyphylla and H. arachnoideus, whereas there was no such trend for the seeds of C. mongolicum and A. squarrosum. The ecological effects of dew on the seed germination and viability of the annual desert plants were species specific. Although dew wetting is insufficient to cause seed germination, it may help in priming the seeds.

关键词： dew deposition seeds hydration and dehydration seeds viability

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Climate warming increases biodiversity of small rodents by favoring rare or less abundant species in a grassland ecosystem

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Integrative Zoology 2013年第2期8卷 162-174页

作者： Guangshun JIANG Jun LIU Lei XU Guirui YU Honglin HE Zhibin ZHANG College of Wildlife Resources Northeast Forestry UniversityHarbinChina Inner Mongolia center for Endemic Diseases Control and research HuhehotChina Information Management Group for the synthesis center of chinese ecosystem research network Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture Institute of ZoologyChinese Academy of SciencesBeijingChina

Our Earth is facing the challenge of accelerating climate change,which imposes a great threat to *** published studies suggest that climate warming may cause a dramatic decline in biodiversity,especially in colder and drier *** this study,we investigated the effects of temperature,precipitation and a normalized difference vegetation index on biodiversity indices of rodent communities in the current or previous year for both detrended and nondetrended data in semi-arid grassland of Inner Mongolia during *** results demonstrate that temperature showed predominantly positive effects on the biodiversity of small rodents;precipitation showed both positive and negative effects;a normalized difference vegetation index showed positive effects;and cross-correlation function values between rodent abundance and temperature were negatively correlated with rodent *** results suggest that recent climate warming increased the biodiversity of small rodents by providing more benefits to population growth of rare or less abundant species than that of more abundant species in Inner Mongolia grassland,which does not support the popular view that global warming would decrease biodiversity in colder and drier *** hypothesized that higher temperatures might benefit rare or less abundant species(with smaller populations and more folivorous diets)by reducing the probability of local extinction and/or by increasing herbaceous food resources.

关键词： climate change cross-correlation function rare species small mammal biodiversity time lag

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Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China,2004-2010

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Journal of Environmental Sciences 2013年第5期25卷 1007-1014页

作者： Xinyu Zhang Zhiwei Xu Xiaomin Sun Wenyi Dong Deborah Ballantine Key Laboratory of ecosystem network Observation and Modelling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences National Institute of Water and Atmospheric research HamiltonNew Zealand

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 *** 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 *** 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 *** 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 *** 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.

关键词： chinese ecosystem research network shallow groundwater agricultural forest ecosystems nitrate concentration

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The Limiting Effect of Deep Soil Water on Evapotranspiration of a Subtropical Coniferous Plantation Subjected to Seasonal Drought

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Advances in Atmospheric Sciences 2014年第2期31卷 385-395页

作者： TANG Yakun WEN Xuefa SUN Xiaomin ZHANG Xinyu WANG Huimin Key Laboratory of ecosystem network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences University of chinese Academy of Sciences

Seasonal drought is a common occurrence in humid *** year 2003 was the driest year during the period 1985-2011 in southeastern *** 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 *** 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 *** 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,*** 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 *** 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.

关键词： ChinaFLUX evapotranspiration seasonal drought subtropical coniferous plantation

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