检索结果-南通市图书馆

Influences of the interannual variability of vegetation LAI on surface temperature

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2016年第4期9卷 292-297页

作者： ZHU Jia-Wen zeng xiao-dong International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology

通过两组模式的集合模拟,本论文研究了植被叶面积指数的年际变化对地表温度的影响。结果表明叶面积指数的年际变化的影响信号整体弱于大气变率的噪声。但是,就空间分布而言,热带地区的影响信号强于中高纬度地区。这主要是由于热带地区... 详细信息

通过两组模式的集合模拟,本论文研究了植被叶面积指数的年际变化对地表温度的影响。结果表明叶面积指数的年际变化的影响信号整体弱于大气变率的噪声。但是,就空间分布而言,热带地区的影响信号强于中高纬度地区。这主要是由于热带地区的叶面积指数通过影响地表蒸散发导致其与地表温度具有显著的线性关系。

关键词：叶面积指数年际变化植被特征地表温度中高纬度地区表面温度植被模型地球系统

Evaluation of the individual allocation scheme and its impacts in a dynamic global vegetation model

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2016年第1期9卷 38-44页

作者： SONG Xiang zeng xiao-dong LI Fang International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science &Technology

植物的生长策略不仅影响生态系统结构,而且对全球碳、水循环也起着至关重要的作用。本文以中国科学院大气物理研究所研发的第一代全球植被动力学模式IAP-DGVM1.0为平台,考察森林生态系统中树的个体生长方案及其影响。结果表明,与观测相... 详细信息

植物的生长策略不仅影响生态系统结构,而且对全球碳、水循环也起着至关重要的作用。本文以中国科学院大气物理研究所研发的第一代全球植被动力学模式IAP-DGVM1.0为平台,考察森林生态系统中树的个体生长方案及其影响。结果表明,与观测相比,模式高估了个体茎生物量,低估了个体叶生物量,从而进一步高估了中国森林生态系统的总生物量和成熟林受干扰后恢复的时间尺度,低估了生态系统净初级生产力和叶面积指数。

关键词：植被模型影响评价配置方案个体净初级生产力生态系统叶面积指数生物量

The Impacts of the Interannual Variability of Vegetation on the Interannual Variability of Global Evapotranspiration: A Modeling Study

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2012年第3期5卷 225-230页

作者： CHEN Hao zeng xiao-dong International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The impact of the interannual variability (IAV) of vegetation on the IAV of evapotranspiration is investigated with the Community Land Model (CLM3.0) and modified Dynamic Global Vegetation Model (DGVM). Two sets of 50-year off-line simulations are used in this study. The simulations begin with the same initial surface-water and heat states and are driven by the same atmospheric forcing data. The vegetation exhibits interannual variability in one simulation but not in the other simulation. However, the climatological means for the vegetation are the same. The IAV of the 50-year annual total evapotranspiration and its three partitions (ground evaporation, canopy evaporation, and transpiration) are analyzed. The global distribution of the evapotranspiration IAV and the statistics of evapotranspiration and its components in different ecosystems show that the IAV of ground evaporation is generally large in areas dominated by grass and deciduous trees, whereas the IAV of canopy evaporation and transpiration is large in areas dominated by bare soil and shrubs. For ground evaporation, canopy evaporation, and transpiration, the changes in IAV are larger than the mean state over most grasslands and shrublands. The study of two sites with the same IAV in the leaf area index (LAI) shows that the component with the smaller contribution to the total evapotranspiration is more sensitive to the IAV of vegetation. The IAV of the three components of evapotranspiration increases with the IAV of the fractional coverage (FC) and the LAI. The ground evaporation IAV shows the greatest increase, whereas the canopy evaporation shows the smallest increase.

关键词：植被模型年际变化蒸散量模拟地面蒸发组成部分统计显示叶面积指数

Comparison of the Influence of Interannual Vegetation Variability between Offline and Online Simulations

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2014年第5期7卷 453-457页

作者： ZHU Jia-Wen zeng xiao-dong International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology

This study investigates the influence of interannual vegetation variability. Two sets of offline and online simulations were performed using the Community Earth System Model. The interannual Global LAnd Surface Satellite(GLASS) leaf area index(LAI) dataset from 1985 to 2000 and its associated climatological LAI were used to replace the default climatological LAI data in version 4 of the Community Land Model(CLM4). The results showed that on a global scale, canopy transpiration and evaporation, as well as total evapotranspiration in offline simulations were significantly positively correlated with LAI, whereas ground evaporation and ground temperature showed significant negative correlation with LAI. However, the correlations in online simulations were reduced markedly because of interactive feedbacks between albedo, changed climatic factors and atmospheric variability. In the offline simulations, the fluctuations of differences in interannual variability of evapotranspiration and ground temperature focused on vegetation growing regions and the magnitudes were smaller. Those in online simulations spread over more regions and the magnitudes were larger. These results highlight the influence of interannual vegetation variability, particularly in online simulations, an effect that deserves consideration and attention when investigating the uncertainty of climate change.

关键词：在线模拟植被变化离线模拟气候因素地面蒸发年际变化叶面积指数地球系统

Evaluating the performance of CMIP6 Earth system models in simulating global vegetation structure and distribution

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2021年第4期12卷 584-595页

作者： SONG Xiang WANG Dan-Yun LI Fang zeng xiao-dong International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing100029China University of Chinese Academy of Sciences Beijing100049China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing210044China

Evaluation of vegetation structure and distribution simulations in Earth system models(ESMs)is the basis for understanding historical reconstruction and future projection of changes in terrestrial ecosystems,carbon cycle,and climate based on these ESMs.Such assessments can also provide important information of models'merits and shortcomings or systematic biases,and so clues for model development.Vegetation structure and distribution in ESMs are primarily characterized by three variables:leaf area index(LAI),tree height,and fractional coverage of plant functional type(PFT).However,for the ongoing Coupled Model Intercomparison Project Phase 6(CMIP6),only temporal variabilities of global-averaged LAI time series were evaluated,others remain largely uninvestigated.This study systematically investigates the spatial and/or temporal variability of the three critical variables from 27 ESMs in CMIP6 using satellite observations.Our results show that all models and the multi-model ensemble mean(MME)can generally reproduce the observed LAI spatial pattern but all of them overestimate the global mean LAI mainly due to overestimation of LAI in non-forested vegetated areas.Most CMIP6 models fail to capture the temporal variability in the annual LAI because of large biases in both the simulated trend magnitude and temporal pattern of interannual variability.The average LAI seasonal cycles in different latitude zones are roughly reproduced by the models,but 1-2 months delays in the LAI peak appear in the Arctic-boreal zone.Additionally,CMIP6 models overall overestimate tree height,and largely overestimate the global grass area but underestimate tree and shrub areas,especially in the middle and high latitudes.It should be kept in mind that such biases may have further impacts on the simulations of the related carbon and land-atmosphere interaction variables(e.g.,ecosystem production,carbon storage,transpiration,and temperature)for global change research.Hence,bias-correction should be made to improve reliability of vegetation str

关键词： Earth system model CMIP6 Leaf area index Vegetation distribution Tree height

Preliminary Assessment of the Common Land Model Coupled with the IAP Dynamic Global Vegetation Model

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2014年第6期7卷 505-509页

作者： ZHU Jia-Wen zeng xiao-dong LI Fang SONG Xiang International Center for Climate and Environment Sciences Institute of Atmospheric Physics (IAP)Chinese Academy of Sciences University of Chinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology

The Common Land Model(CoLM) was coupled with the IAP Dynamic Global Vegetation Model(IAPDGVM), and the performance of this combined CoLMIAP model was evaluated. Offline simulations using both the original Common Land Model(CoLM-LPJ) and CoLM-IAP were conducted. The CoLM-IAP coupled model showed a significant improvement over CoLMLPJ, as the deciduous tree distribution decreased over temperate and boreal regions, while the distribution of evergreen trees increased over the tropics. Some biases in CoLM-LPJ were preserved, including the overestimation of evergreen trees in tropical savanna, the underestimation of boreal evergreen trees, and the absence of boreal shrubs. However, most of these biases did not exist in a further coupled simulation of IAP-DGVM with the Community Land Model(CLM), for which the parameters of IAP-DGVM were optimized. This implies that further improvement is needed to deal with the differences between CoLM and CLM in parameterizations of landbased physical and biochemical processes.

关键词：植被模型 IAP 土地评估常绿乔木热带稀树草原过程模型耦合模型

在线全文

学校读者我要写书评

暂无评论

教师质量:一个概念框架

当代教育与文化 2024年第2期16卷 27-33,82页

作者：都丽萍曾晓东北京联合大学师范学院北京100011 北京师范大学教育学部北京100875

长期以来对基础教育教师质量的内涵缺乏共识,其重要原因在于教师质量观的多元和动态。基于质量内涵的变迁和教师职业特征分析,教师质量应包括教师个人质量、教师团队质量、学校组织质量三个层次。当前,提升基础教育教师质量的重点要从... 详细信息

长期以来对基础教育教师质量的内涵缺乏共识,其重要原因在于教师质量观的多元和动态。基于质量内涵的变迁和教师职业特征分析,教师质量应包括教师个人质量、教师团队质量、学校组织质量三个层次。当前,提升基础教育教师质量的重点要从监管教师个体转向引导和培育教师团队和建设卓越学校。

关键词：教师质量个人质量团队质量学校组织卓越

A Simulation for Stinulus-dependent Neuronal Oscillations in the Visual Cortex

在线全文

学校读者我要写书评

暂无评论

A Simulation for Stinulus-dependent Neuronal Oscillations in...

Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China

IJCNN International Joint Conference on Neural Networks

作者： Qi Xiang lin Wang Meng zeng xiao dong Wang Yun jiu Visual Information Processing Laboratory Institute of BiophysicsAcademia Sinica

In recent years there has been a growing interest in the description of dynamics in complex systems,both at the theoretical and experimental level.In the field of brain research,some investigators attempted to adapt these methods to the analysis of single neuron spike trains,others to the description of more global electrophysiological measurements.Stimulus-related oscillatory firing activity of neural responses has been found in the olfactory bulb as well as in the cat visual cortex.Gray and Singer have shown that neurons in the cat visual cortex have oscillatory responses in the range 40-60 Hz which occur in synchrony for cells in a functional column and are tightly correlated with a local oscillatory field potential.Recently,they obtained evidence that such oscillatory responses can synchronize across columns.Many researchers are very interested in this discovery in biology.These results of their experiments support the theoretical viewpoint of neural wave representation proposed by us. We could consider the oscillations in the visual cortex as an intrinsic phenomenon of a single column.In this paper,the emergence of oscillations in single column was simulated by means of AST 336 personal computer.Some physiological evidence indicate that within relatively small volumes of cortical tissue there exist many cells with very nearly identical responses to identical stimuli.According to the assumption that all nervous processes of any complexity are dependent upon the interaction of excitatory and inhibitory cells,we consider a localized neural population as being composed of an excitatory subpopulation and an inhibitory subpopulation in our model.Each neuron in the two subpopulations can be defined the proportion of excitatory neurons firing per unit time at the instant t,e(t) or i(t) for inhibitory neurons.Within a column each neurons is coupled to all others.We take the following set of differential equations proposed by H.G. Schuster and P.Wagner as a model to simulating:

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Plant Diversity 2024年第3期46卷 353-361页

作者： Jingya Zhang Cui xiao xiaoyu Duan Xin Gao Hao zeng Rong'an dong Gang Feng Keping Ma Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau&Inner Mongolia Key Laboratory of Grassland Ecology School of Ecology and EnvironmentInner Mongolia UniversityHohhot 010021China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China

Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.

关键词： Biological specimen Collection preference Dominant plant species Environmental range Geographical range Species traits