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Regional coupled C-N-H2O cycle processes and associated driving mechanisms

Science China Earth Sciences 2020年第9期63卷 1227-1236页

作者： Yang GAO Gui-Rui YU Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

From a molecular level to an ecosystem scale,different coupling mechanisms take place during coupled carbonnitrogen-water(C-N-H2O)cycle,of which essential are water flux and related biogeochemical processes through physicochemical reactions associated with terrestrial and aquatic ***,regional coupled C-N-H2O cycle will subsequently impact regional gross primary productivity(GPP)and C and N exchanges during air-water interactions that occur downstream of *** study aimed to first synthetically analyze the regional dynamics of C,N and H2O cycles in ecosystems and determine their interactional relationships;second,to specify regional C-N-H2O coupled relationships of ecosystems and their theoretical ecological principles;third,to classify coupled regional response and adaptation of the C-N-H2O cycle to climatic and environmental changes under anthropogenic activities,providing a theoretical basis to fully understand and make adjustments to interactional C,N and H2O cycling relationships at different ecosystem scales and under associated coupling processes.

关键词： Regional C-N-H2O cycle Coupled relationship C cycle N cycle Water cycle Driving mechanisms

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Quick estimation of parameters for the land surface data assimilation system and its influence based on the extended Kalman filter and automatic differentiation

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Science China Earth Sciences 2023年第11期66卷 2546-2562页

作者： Jiaxin TIAN Hui LU Kun YANG Jun QIN Long ZHAO Jianhong ZHOU Yaozhi JIANG Xiaogang MA Department of Earth System Science Ministry of Education Key Laboratory for Earth System ModelingInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China National Tibetan Plateau Data Center Key Laboratory of Tibetan Environmental Changes and Land Surfaces ProcessesInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouth-west UniversityChongqing 400715China Tsinghua University(Department of Earth System Science)-Xi’an Institute of Surveying and Mapping Joint Research Center for Next-Generation Smart Mapping Beijing 100084China

Soil moisture plays a crucial role in drought monitoring,flood forecasting,and water resource *** assimilation methods can integrate the strengths of land surface models(LSM)and remote sensing data to generate highprecision and spatio-temporally continuous soil moisture ***,one of the challenges of the land data assimilation system(LDAS)is how to accurately estimate model and observation *** address this,we had previously proposed a dualcycle assimilation algorithm that can simultaneously estimate the model and observation errors,LSM parameters,and observation operator ***,this algorithm requires a large ensemble size to guarantee stable parameter estimates,resulting in low efficiency and limiting its large-scale *** address this limitation,the authors employed the following approaches:(1)using automatic differentiation to compute the Jacobian matrix of LSM instead of constructing a tangent linear model of LSM,and(2)replacing the ensemble Kalman filter framework with the extended Kalman filter(EKF)framework to improve the efficiency of parameter optimization for the dual-cycle *** EKF-based dual-cycle algorithm accelerated the parameter estimation efficiency near 60 times during a 90-day time period with a model integration time step of 1 *** evaluate the dual-cycle LDAS at the regional-scale,it was applied to assimilate the SMAP soil moisture over the Tibetan Plateau,and soil moisture estimates were validated using in situ observations from four different climatic *** results showed that the EKF-based dual-cycle LDAS corrected biases in both the model and observations and produced more accurate estimates of soil moisture,land surface temperature,and evapotranspiration than did the open loop with default ***,the spatial distribution of soil parameters(sand content,clay content,and porosity)obtained from the LDAS was more reasonable than those of default *** EKF-based

关键词： Soil moisture Data assimilation Parameter optimization Bias correction Error estimation Automatic differentiation

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Significant Difference between Temporal and Spatial Scales Regarding the Response of Soil Respiration to Temperature and Precipitation in China's Terrestrial ecosystems

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SSRN 2023年

作者： Zhao, Wei Yang, Meng Yu, Guirui Chen, Zhi Wang, Qiufeng Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China

In the context of increasing CO2 concentrations and climate warming, there are large uncertainties regarding the regulatory mechanisms of soil respiration and its accurate assessment. As an area sensitive to global climate change, China covers a broad range of longitudes, latitudes, and altitudes, and it is of great significance to study the spatial and temporal patterns of soil respiration and its environmental response in China's terrestrial ecosystems to clarify the mechanisms of regional and global carbon balance processes and their assessment. Based on the expanded annual soil respiration dataset from 1993 to 2020, we re-evaluated soil respiration in China's terrestrial ecosystems and its responses to environmental factors. The mean annual soil respiration in China's terrestrial ecosystems was 777.90 ± 489.43 g C m-2 yr-1, with soil respiration in wetlands being higher than that of the forest, grassland, shrubland, cropland, and desert. Soil respiration showed a significant upward trend between 1993 and 2020, which was mainly caused by a significant increase in soil respiration in grasslands due to increasing precipitation. In addition, we found differences in the environmental factors influencing the interannual and spatial variability of soil respiration. MAP dominated the interannual variability of soil respiration in China, whereas MAT and MAP jointly controlled the spatial variability of soil respiration in China. The response sensitivity of soil respiration to interannual climate variability was significantly higher than its response sensitivity to spatial variability, possibly one of the reasons for the relatively low accuracy of the present statistical models, which do not distinguish between temporal and spatial responses. More studies are needed to quantify the response of soil respiration to environmental changes at temporal and spatial scales and to construct soil respiration models considering two-dimensional responses in time and space. © 2023, Th

关键词： Climate change

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Strong Inhibiting Effect of Daytime Warming But Weak Promoting Effect of Nighttime Warming on Carbon Use Efficiency in Northern Hemisphere

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SSRN 2023年

作者： Sun, Yihan Zhang, Yangjian Zheng, Zhoutao Zhao, Guang Zhu, Yixuan Gao, Jie Zhang, Yu Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100190 China

Asymmetric diurnal warming broadly affects terrestrial ecosystem carbon cycling in the Northern Hemisphere. Vegetation photosynthesis mostly occurs in the daytime and respiration occurs during the whole day. Then the asymmetrical diurnal warming will certainly affect the ratio between net ecosystem productivity (NPP) against gross ecosystem productivity (GPP), i.e. vegetation carbon use efficiency (CUE). However, this kind of study has rarely been reported on a global scale. Using long-term productivity datasets from MODIS and land surface models, we investigated spatiotemporal response patterns of CUE to daytime (Tmax) and nighttime (Tmin) temperature changes across the Northern Hemisphere (>30°N) spanning 2000-2019. Regions exhibiting a positive correlation between Tmax and CUE were extensive throughout the growing season in most northern ecosystems, with a greater magnitude in summer than in spring and autumn. Tmin tended to cause a positive impact on CUE in spring and autumn, while being correlated negatively with summer CUE, resulting in a weak positive relationship between CUE and Tmin. Divergences in the strength and direction of productivity and respiratory responses to diurnal warming lead to spatial and seasonal patterns between CUE and Tmax or Tmin, which is regulated by soil moisture. Our findings provide an in-depth understanding of how the interaction between asymmetric diurnal warming and water limitations regulates the spatiotemporal variations of vegetation product allocation, which is vital for predicting future carbon dynamics under climate warming. © 2023, The Authors. All rights reserved.

关键词： Vegetation

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Nitrogen storage and allocation in China’s forest ecosystems

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Science China Earth Sciences 2020年第10期63卷 1475-1484页

作者： Li XU Nianpeng HE Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Forests are important parts of terrestrial ecosystems and play a leading role in regional and global nitrogen(N)*** assessment of N storage and allocation in China’s forests is critical to improve the accuracy of regional or global N estimates and to guide policy-makers in the formulation of scientific and effective N management ***,the fore stN storage at national scale remains *** on 4420 forest field-investigated data,we investigated the N storage allocation in China’s forests,explored the spatial patterns and influence *** data included vegetation information on various organs(i.e.,leaf,branch,stem,and root)and soil information at different depths(0-30 cm and 0-100 cm).The total N storage in China’s forest ecosystems was 14.45±8.42 tN hm^–2;0.86±0.51 tN hm^–2(5.95%)in vegetation and 13.59±8.40 tN hm^–2(94.05%)in soil(0–100 cm).The storage and allocation of N varied significantly across various regions and forest *** different ecological regions,N storage varied from 10.34 to 23.11 tN hm^–2,and the allocation ratio of N storage between vegetation and soil(0–100 cm)varied from 0.03 to *** different forest types,the N storage varied from 12.87 to 18.32 tN hm^–2,and the allocation ratio of N storage between vegetation and soil(0–100 cm)varied from 0.03 to *** spatial patterns relative to N storage and allocation in forests were *** was the primary factor influencing the spatial variation in forestN storage,while soil texture was the main factor influencing the spatial variation in N *** first estimates of N storage and allocation ratio in China’s forests are keys for improving the fitting accuracy of regional N cycle models and provide a reference for regional management of forestN.

关键词： Forest Nitrogen cycling Nitrogen storage Allocation Climate Soil nutrient Soil texture

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The Facilitation of Restoration by Cushion Plant Androsace tapete in a Degraded Alpine Grassland

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Journal of Resources and Ecology 2022年第1期13卷 107-112页

作者： HE Yongtao WANG Fang NIU Ben WANG Zhipeng LI Meng SHI Peili ZHANG Xianzhou Lhasa Plateau Ecosystem Research Station Key Laboratory of Ecosystem Network Observation and ModelingInstitute of Geographic Sciences andNatural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100190China

The cushion plant Androsace tapete is an endemic species that is widely distributed in the Qinghai-Tibetan Plateau, and also predominant in the alpine grassland that is locally degraded due to overgrazing and other reasons. As an ecosystem engineer cushion plant, its ability to facilitate the restoration of degraded alpine grassland was studied in a degraded alpine grassland at an elevation of 4500 m on the southern slope of the Nyainqentanglha Mountains in Damxung. The species diversity, soil nutrients and water content underneath and outside the cushion plant A. tapete were investigated. The results showed that soil nutrients underneath the A. tapete cushion were significantly increased by about 16%-48% compared to outside the cushion, of which the organic matter and total N were increased by 16.2% and 18.9% respectively, and the soil water content was increased about 12%. The index of species diversity of richness(S), Shannon-Wiener’s H and Simpson’s D all increased with the coverage of cushion plant A. tapete. Our results suggested that this cushion plant can facilitate restoration of the degraded alpine grassland by modifying the local soil environment and increasing the community diversity, so it should be conserved for the restoration of degraded alpine grasslands on the Qinghai-Tibetan Plateau.

关键词： cushion plant facilitation degraded alpine meadow species diversity soil nutrients

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Variations of Vegetation Phenology Extracted from Remote Sensing Data over the Tibetan Plateau Hinterland during 2000–2014

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Journal of Meteorological Research 2020年第4期34卷 786-797页

作者： Ya LIU Junbang WANG Jinwei DONG Shaoqiang WANG Hui YE Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural ResourcesChinese Academy of SciencesBeijing 100101 Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008

How vegetation phenology responds to climate change is a key to the understanding of the mechanisms driving historic and future changes in regional terrestrial ecosystem productivity. Based on the 250-m and 8-day moderate resolution imaging spectroradiometer(MODIS) normalized difference vegetation index(NDVI) data for 2000-2014 in the Three-River Source Region(TRSR) of Qinghai Province, China, i.e., the hinterland of the Tibetan Plateau, we extracted relevant vegetation phenological information(e.g., start, end, and length of growing season) and analyzed the changes in the TRSR vegetation in response to climate change. The results reveal that, under the increasingly warm and humid climate, the start of vegetation growing season(SOS) advanced 1.03 day yr-1 while the end of vegetation growing season(EOS) exhibited no significant changes, which led to extended growing season length. It is found that the SOS was greatly affected by the preceding winter precipitation, with progressively enhanced precipitation facilitating an earlier SOS. Moreover, as the variations of SOS and its trend depended strongly on topography, we estimated the elevation break-points for SOS. The lower the elevations were, the earlier the SOS started. In the areas below 3095-m elevation, the SOS delay changed rapidly with increasing elevation;whereas above that, the SOS changes were relatively minor. The SOS trend had three elevation break-points at 2660, 3880, and 5240 m.

关键词： Three-River Source Region(TRSR) start of vegetation growing season(SOS) spatiotemporal change elevation climate change China

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The role of herbivores in the grassland carbon budget for Three-Rivers Headwaters region,Qinghai-Tibetan Plateau,China

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Grassland Research 2022年第3期1卷 207-219页

作者： Junbang Wang Xinquan Zhao Xihuang Ouyang Liang Zhao Wenying Wang Chan Zuo Zhenhua Zhang Huakun Zhou Alan Watson Yingnian Li Key Laboratory of Ecosystem Network Observation and Modeling National Ecosystem Science Data CenterInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina State Key Laboratory of Plateau Ecology and Agriculture Qinghai UniversityXiningChina Qinghai Provincial Key Laboratory of Restoration Ecology for Cold Region Northwest Institute of Plateau BiologyChinese Academy of SciencesXiningChina University of Chinese Academy of Sciences BeijingChina College of Life Sciences Qinghai Normal UniversityXiningChina Rocky Mountain Research Station USDA Forest ServiceMissoulaMontanaUSA

Background:An accurate assessment of the carbon budget is a crucial part of projecting future climate change and its impact on *** foster multiple ecological functions including support for wild animals and *** intake forage biomass carbon,then digest and metabolize,and finally retain some *** carbon processes have not been well quantified,resulting in uncertainties in the estimation of regional carbon budgets for grassland ***:An animal metabolic carbon flux model was developed for herbivores in the Three-Rivers Headwaters region of *** forage intake and metabolic carbon rates were estimated through metabolic body weight and daily digested measures for the main herbivore ***:The carbon intake was 5.52 Tg C year−1(45%)from partial aboveground biomass(12.2 Tg C year−1),in which 39.31%was released into the atmosphere by respiration CO_(2),43.77%was returned to the ecosystem as feces and urine,and 16.96%was retained in herbivores for population regeneration or for human ***:This study,as the first research on this topic,quantified the carbon flux of herbivores and found livestock accounts for a major part of consumed carbon on grasslands,which is important for understanding regional carbon budgets to mitigate and adapt to climate change over grasslands worldwide.

关键词： aboveground biomass alpine grassland carbon budget herbivores livestock metabolism

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Correction to: Species-specific and generalized allometric biomass models for eight Fagaceae species in the understory of evergreen broadleaved forests in subtropical China

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Journal of Forestry Research 2024年第6期35卷 374-374页

作者： Meng, Shengwang Qianyanzhou Ecological Research Station Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing People’s Republic of China

In the original publication, the author has found few errors in the equations as below:1. The ε_(fO) symbol in Wag model of Eq. (6) should be deleted. The incorrect equation appears as below.

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Terrestrial carbon sinks in China and around the world and their contribution to carbon neutrality

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Science China(Life Sciences) 2022年第5期65卷 861-895页

作者： Yuanhe Yang Yue Shi Wenjuan Sun Jinfeng Chang Jianxiao Zhu Leiyi Chen Xin Wang Yanpei Guo Hongtu Zhang Lingfei Yu Shuqing Zhao Kang Xu Jiangling Zhu Haihua Shen Yuanyuan Wang Yunfeng Peng Xia Zhao Xiangping Wang Huifeng Hu Shiping Chen Mei Huang Xuefa Wen Shaopeng Wang Biao Zhu Shuli Niu Zhiyao Tang Lingli Liu Jingyun Fang State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China College of Environmental and Resource Sciences Zhejiang UniversityHangzhou 310058China State Key Laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020China Institute of Ecology College of Urban and Environmental SciencesLaboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China School of Ecology and Nature Conservation Beijing Forest UniversityBeijing 100083China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Enhancing the terrestrial ecosystem carbon sink(referred to as terrestrial C sink) is an important way to slow down the continuous increase in atmospheric carbon dioxide(CO_(2)) concentration and to achieve carbon neutrality *** better understand the characteristics of terrestrial C sinks and their contribution to carbon neutrality,this review summarizes major progress in terrestrial C budget researches during the past decades,clarifies spatial patterns and drivers of terrestrial C sources and sinks in China and around the world,and examines the role of terrestrial C sinks in achieving carbon neutrality *** to recent studies,the global terrestrial C sink has been increasing from a source of (-0.2±0.9) Pg C yr^(-1)(1 Pg=1015g)in the 1960s to a sink of (1.9±1.1) Pg C yr^(-1) in the *** synthesizing the published data,we estimate terrestrial C sink of 0.20–0.25 Pg C yr^(-1) in China during the past decades,and predict it to be 0.15–0.52 Pg C yr^(-1) by *** terrestrial C sinks are mainly located in the mid-and high latitudes of the Northern Hemisphere,while tropical regions act as a weak C sink or *** C balance differs much among ecosystem types:forest is the major C sink;shrubland,wetland and farmland soil act as C sinks;and whether the grassland functions as C sink or source remains *** might be a C sink,but the magnitude and the associated mechanisms are still *** atmospheric CO_(2) concentration,nitrogen deposition,climate change,and land cover change are the main drivers of terrestrial C sinks,while other factors such as fires and aerosols would also affect ecosystem C *** driving factors of terrestrial C sink differ among *** CO_(2) concentration and climate change are major drivers of the C sinks in North America and Europe,while afforestation and ecological restoration are additionally important forcing factors of terrestrial C sinks in *** future studies,we recommend th

关键词： terrestrial ecosystem carbon sink carbon neutrality carbon cycle global warming

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