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Comprehensive Study on the Influence of Evapotranspiration and Albedo on Surface Temperature Related to Changes in the Leaf Area Index

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Advances in Atmospheric Sciences 2015年第7期32卷 935-942页

作者： ZHU Jiawen zeng xiaodong International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese 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

Many studies have investigated the influence of evapotranspiration and albedo and emphasize their separate effects but ignore their interactive influences by changing vegetation status in large amplitudes. This paper focuses on the comprehensive influence of evapotranspiration and albedo on surface temperature by changing the leaf area index （LAD between 30^-90~N. Two LAI datasets with seasonally different amplitudes of vegetation change between 30^-90~N were used in the simulations. Seasonal differences between the results of the simulations are compared, and the major findings are as follows. （1） The interactive effects of evapotranspiration and albedo on surface temperature were different over different regions during three seasons [March-April-May （MAM）, June-July-August （JJA）, and September-October-November （SON）], i.e., they were always the same over the southeastern United States during these three seasons but were opposite over most regions between 30°-90°N during JJA. （2） Either evapotranspiration or albedo tended to be dominant over different areas and during different seasons. For example, evapotranspiration dominated almost all regions between 30^-90~N during JJA, whereas albedo played a dominant role over northwestern Eurasia during MAM and over central Eurasia during SON. （3） The response of evapotranspiration and albedo to an increase in LAI with different ranges showed different paces and signals. With relatively small amplitudes of increased LAI, the rate of the relative increase in evapotranspiration was quick, and positive changes happened in albedo. But both relative changes in evapotranspiration and albedo tended to be gentle, and the ratio of negative changes of albedo increased with relatively large increased amplitudes of LAI.

关键词： surface temperature evapotranspiration albedo leaf area index comprehensive influence

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Interception Algorithm of S-cubed Signal Model in Stealth Radar Equipment

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Chinese Journal of Aeronautics 2012年第3期25卷 416-422页

作者： zeng xiaodong TANG Bin XIONG Ying School of Electronic Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

Radar equipment of stealth platforms such as aircraft have adopted the newest modem technology to design the signal waveforms. One of the important and effective methods is the hybrid waveform called spread spectrum stretch （S-cubed） which combines linear frequency modulation （LFM） and discrete phase code. In order to investigate the function of enemy＇s stealth radar equipment, the interception algorithm of S-cubed is needed. In this paper, a novel detection and parameter estimation approach for the reconnaissance S-cubed radar signal is presented. First, the generalized time-frequency representation of Zhao, Atlas, and Marks （ZAM-GTFR） and Hough transforms （HT） are applied to detecting the signal, and then the initial frequency and modulation slope of LFM are estimated from the ZAM-GTFR. On the basis of LFM information, the reconstructing signal is generated. Finally, the code rate of discrete phase code is extracted from the negative peaks of the ZAM-GTFR. Simulation results show that the proposed algorithm has higher estimation accuracy when the signal to noise ratio （SNR） is above 3 dB.

关键词： signal detection parameter estimation spread spectrum stretch (S-cubed) generalized time-frequency representation (GTFR) Hough transforms

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GEOLOGICAL FEATURE OF YUNKAI RIFT

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中国有色金属学会会刊：英文版 1998年第1期8卷 161-164页

作者： Li, Peizheng zeng, xiaodong Deng, Jiqiu Central South Univ of Technology Changsha China

ＧＥＯＬＯＧＩＣＡＬＦＥＡＴＵＲＥＯＦＹＵＮＫＡＩＲＩＦＴ①ＬｉＰｅｉｚｈｅｎｇ，ＺｅｎｇＸｉａｏｄｏｎｇａｎｄＤｅｎｇＪｉｑｉｕＣｏｌｅｇｅｏｆＲｅｓｏｕｒｃｅ，ＥｎｖｉｒｏｎｍｅｎｔａｎｄＣｉｖｉｌＥｎｇｉｎｅｒ... 详细信息

ＧＥＯＬＯＧＩＣＡＬＦＥＡＴＵＲＥＯＦＹＵＮＫＡＩＲＩＦＴ①ＬｉＰｅｉｚｈｅｎｇ，ＺｅｎｇＸｉａｏｄｏｎｇａｎｄＤｅｎｇＪｉｑｉｕＣｏｌｅｇｅｏｆＲｅｓｏｕｒｃｅ，ＥｎｖｉｒｏｎｍｅｎｔａｎｄＣｉｖｉｌＥｎｇｉｎｅｒｉｎｇ，ＣｅｎｔｒａｌＳｏｕｔｈＵ...

关键词： Yunkai rift edge faults sedimentary formation evolution history

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Parameterization of height-diameter and crown radius-diameter relationships across the globe

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Journal of Plant Ecology 2024年第2期17卷 36-48页

作者： Xiang Song Jinxu Li xiaodong zeng International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China School of Mathematics and Statistics North China University of Water Resources and Electric PowerZhengzhou 450046China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The tree height-diameter at breast height(H-DBH)and crown radius-DBH(CR-DBH)relationships are key for forest carbon/biomass estimation,parameterization in vegetation models and vegetation-atmosphere *** the H-DBH relationship has been widely investigated on site or regional scales,and a few of studies have involved CR-DBH relationships based on plot-level data,few studies have quantitatively verifed the universality of these two relationships on a global *** study evaluated the ability of 29 functions to ft the H-DBH and CR-DBH relationships for six different plant functional types(PFTs)on a global scale,based on a global plant trait *** showed that most functions were able to capture the H-DBH relationship for tropical PFTs and boreal needleleaf trees relatively accurately,but slightly less for temperate PFTs and boreal broadleaf trees(BB).For boreal PFTs,the S-shaped Logistic function ftted the H-DBH relationship best,while for temperate PFTs the Chapman-Richards function performed *** tropical needleleaf trees,the fractional function of DBH satisfactorily captured the H-DBH relationship,while for tropical broadleaf trees,the Weibull function and a composite function of fractions were the best *** CR-DBH,the ftting capabilities of all the functions were comparable for all PFTs except *** Logistic function performed best for two boreal PFTs and temperate broadleaf trees,but for temperate needleleaf trees and two tropical PFTs,some exponential functions demonstrated higher *** work provides valuable information for parameterization improvements in vegetation models and forest feld investigations.

关键词： tree height diameter at breast height crown radius ftting function parameterization vegetation model

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Parameterization of Tree and Shrub Stem Wood Density Adaptions to Multiple Climate and Soil Factor Gradients

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Advances in Atmospheric Sciences 2024年第12期41卷 2419-2431页

作者： Xiang SONG Jinxu LI xiaodong zeng International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Wood density(WD)is an important quality and functional trait of ***,despite the relationships between WD and abiotic factors being important to model or predict spatial distributions of functional traits,as well as responses of vegetation to climate changes,in current Earth system models or dynamic global vegetation models(ESMs/DGVMs),WD is often oversimplified,being defined as a globally uniform constant either for all plant functional types(PFTs)or for each individual *** oversimplifications may lead to simulation biases in the morphology of woody PFTs,as well as ecosystem transition and vegetation-atmosphere ***,existing conclusions about the relationships between WD and abiotic factors drawn from field observations remain mixed,making model parameterization improvements *** study systematically investigated the influences of climate and soil factors on WD across various *** fitting models for predicting WD within each PFT were then constructed by utilizing our collated global database of 138604 *** WDs of tree PFTs,climate emerges as a more influential factor than soil characteristics,whereas for shrub PFTs the effects of climate and soil are of equivalent *** all six PFTs,correlation coefficients between predictions by fitting models and observed WD range from 0.49 to *** predicted and observed WD exhibit good agreement across climate *** is expected that the incorporation of our research findings into DGVMs will improve the simulation of tree height and forest fractional coverage,particularly in the central forest areas and forest transition zones.

关键词： wood density abiotic factors fitting models plant functional type vegetation model

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Investigation of Uncertainties of Establishment Schemes in Dynamic Global Vegetation Models

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Advances in Atmospheric Sciences 2014年第1期31卷 85-94页

作者： zeng xiaodong LI Fang SONG Xiang International Center for Climate and Environmental Sciences Institute of Atmospheric Physics Chinese Academy of Sciences

In Dynamic Global Vegetation Models （DGVMs）, the establishment of woody vegetation refers to flowering, fertiliza- tion, seed production, germination, and the growth of tree seedlings. It determines not only the population densities but also other important ecosystem structural variables. In current DGVMs, establishments of woody plant functional types （PFTs） are assumed to be either the same in the same grid cell, or largely stochastic. We investigated the uncertainties in the competition of establishment among coexisting woody PFTs from three aspects： the dependence of PFT establishments on vegetation states; background establishment; and relative establishment potentials of different PFTs. Sensitivity experi- ments showed that the dependence of establishment rate on the fractional coverage of a PFT favored the dominant PFT by increasing its share in establishment. While a small background establishment rate had little impact on equilibrium states of the ecosystem, it did change the timescale required for the establishment of alien species in pre-existing forest due to their disadvantage in seed competition during the early stage of invasion. Meanwhile, establishment purely fiom background （the scheme commonly used in current DGVMs） led to inconsistent behavior in response to the change in PFT specification （e.g., number of PFTs and their specification）. Furthermore, the results also indicated that trade-off between irtdividual growth and reproduction/colonization has significant influences on the competition of establishment. Hence, further development of es- tablishment parameterization in DGVMs is essential in reducing the uncertainties in simulations of both ecosystem structures and successions.

关键词： Dynamic Global Vegetation Model uncertainty establishment scheme PFT classification fractional coverage

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Development of the IAP Dynamic Global Vegetation Model

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Advances in Atmospheric Sciences 2014年第3期31卷 505-514页

作者： zeng xiaodong LI Fang SONG Xiang International Center for Climate and Environmental Sciences Institute of Atmospheric Physics Chinese Academy of Sciences

ABSTRACT The lAP Dynamic Global Vegetation Model （IAP-DGVM） has been developed to simulate the distribution and structure of global vegetation within the framework of Earth System Models. It incorporates our group＇s recent developments of major model components such as the shrub sub-model, establishment and competition parameterization schemes, and a process-based fire parameterization of intermediate complexity. The model has 12 plant functional types, including seven tree, two shrub, and three grass types, plus bare soil. Different PFTs are allowed to coexist within a grid cell, and their state variables are updated by various governing equations describing vegetation processes from fine-scale biogeophysics and biogeochemistry, to individual and population dynamics, to large-scale biogeography. Environmental disturbance due to fire not only affects regional vegetation competition, but also influences atmospheric chemistry and aerosol emissions. Simulations under observed atmospheric conditions showed that the model can correctly reproduce the global distribution of trees, shrubs, grasses, and bare soil. The simulated global dominant vegetation types reproduce the transition from forest to grassland （savanna） in the tropical region, and from forest to shrubland in the boreal region, but overestimate the region of temperate forest.

关键词： Dynamic Global Vegetation Model individual and population dynamics biogeography disturbance

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Trend in seasonal amplitude of northern net ecosystem production:Simulated results from IAP DGVM in CAS-ESM2

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Atmospheric and Oceanic Science Letters 2024年第2期17卷 45-51页

作者： Jiawen Zhu xiaodong zeng International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjingChina University of Chinese Academy of Sciences BeijingChina

北方陆地净生态系统生产力(NEP)具有明显的季节变化特征,这是大气CO_(2)季节变化的关键驱动.研究这些碳循环过程并理解潜在的驱动因素是气候研究的一个关键问题.本文利用第二代中国科学院地球系统模式(CAS-ESM2)中的全球植被动态模型(IA... 详细信息

北方陆地净生态系统生产力(NEP)具有明显的季节变化特征,这是大气CO_(2)季节变化的关键驱动.研究这些碳循环过程并理解潜在的驱动因素是气候研究的一个关键问题.本文利用第二代中国科学院地球系统模式(CAS-ESM2)中的全球植被动态模型(IAPDGVM),研究了1990-2014年北方NEP(40°-90°N)的季节振幅及其变化趋势.在初始化试验的基础上,本文开展了一个控制试验来评估模拟的北方NEP季节幅度的变化趋势,同时开展了三个敏感性试验来研究气候和大气CO_(2)的贡献.结果表明:1990-2014年,模拟的北方NEP季节振幅显著增加,趋势为9.69万吨碳/月/年,这主要是由于最大NEP增加所致.当分别排除CO_(2)施肥效应和气候效应时,上述增加趋势大大减弱.这些显著的减少表明大气CO_(2)和气候变化对北方NEP的季节性振幅有重要影响.尽管模式存在不确定性,但这些结果有利于进一步提升IAPDGVM对陆地碳循环的精确模拟,也为CAS-ESM研究碳-气候相互作用的应用提供了重要参考.

关键词：净生态系统生产力北方陆地生态系统季节变化幅度 CO_(2)施肥效应气候效应

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Development of an Establishment Scheme for a DGVM

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Advances in Atmospheric Sciences 2016年第7期33卷 829-840页

作者： Xiang SONG xiaodong zeng Jiawen ZHU Pu SHAO International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of lnformation Science&TechnologyNanjing 210044 University of Chinese Academy of Sciences Beijing 100049

Environmental changes are expected to shift the distribution and abundance of vegetation by determining seedling estab- lishment and success. However, most current ecosystem models only focus on the impacts of abiotic factors on biogeophysics （e.g., global distribution, etc.）, ignoring their roles in the population dynamics （e.g., seedling establishment rate, mortality rate, etc.） of ecological communities. Such neglect may lead to biases in ecosystem population dynamics （such as changes in population density for woody species in forest ecosystems） and characteristics. In the present study, a new establishment scheme for introducing soil water as a function rather than a threshold was developed and validated, using version 1.0 of the IAP-DGVM as a test bed. The results showed that soil water in the establishment scheme had a remarkable influence on forest transition zones. Compared with the original scheme, the new scheme significantly improved simulations of tree population density, especially in the peripheral areas of forests and transition zones. Consequently, biases in forest fractional coverage were reduced in approximately 78.8% of the global grid cells. The global simulated areas of tree, shrub, grass and bare soil performed better, where the relative biases were reduced from 34.3% to 4.8%, from 27.6% to 13.1%, from 55.2% to 9.2%, and from 37.6% to 3.6%, respectively. Furthermore, the new scheme had more reasonable dependencies of plant functional types （PFTs） on mean annual precipitation, and described the correct dominant PFTs in the tropical rainforest peripheral areas of the Amazon and central Africa.

关键词： establishment scheme soil water IAP-DGVM1.0 forest population density fractional coverage

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Changes in the seasonal amplitude of northern ecosystem productivity under future global warming

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Atmospheric and Oceanic Science Letters 2023年第3期16卷 1-6页

作者： Jiawen Zhu Xiaofei Gao xiaodong zeng International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjingChina University of Chinese Academy of Sciences BeijingChina

观测显示过去几十年北半球大气二氧化碳季节幅度大幅增加,这主要是由北半球陆地净生态系统生产力季节幅度的增加所致。但是,因为气候变化和植被动态的不确定性,未来陆地净生态系统生产力季节幅度的变化还很不清楚.本工作利用全球植被动... 详细信息

观测显示过去几十年北半球大气二氧化碳季节幅度大幅增加,这主要是由北半球陆地净生态系统生产力季节幅度的增加所致。但是,因为气候变化和植被动态的不确定性,未来陆地净生态系统生产力季节幅度的变化还很不清楚.本工作利用全球植被动力学模式研究了全球变暖背景下北纬45°以北陆地净生态系统生产力季节幅度的变化.作者做了两大类试验:当代试验(1981-2000)和CMIP5RCP8.5变暖情景驱动的未来试验(2081-2100).结果显示,在RCP8.5变暖情景下北半球中高纬陆地净生态系统生产力季节幅度整体增加,这是因为陆地净生态系统生产力的月最大值增加且月最小值减小.最大(最小)陆地净生态系统生产力的增加(减小)是由于总初级生产力的增加强(弱)于生态系统总呼吸,总初级生产力和生态系统总呼吸的变化都主要受地表气温和植被动态的驱动.本工作强调了植被动态对北半球中高纬陆地生态系统碳循环的关键调制作用,也强调了在地球系统模式中包含全球植被动力学模式的重要性。

关键词：陆地生态系统碳循环全球变暖植被动态碳循环的季节变化

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