基于MOD17A3的图们江流域植被NPP时空变化特征

利用遥感技术,基于MOD17A3数据分析了图们江流域2000—2015年共16年的NPP动态变化.结果表明,2000—2015年图们江流域NPP总体呈上升趋势,2012年NPP值达到最大,最小值出现在2007年,平均每年上升4.04 gC·m~(-2)·a~(-1);图们江上游NPP表现出最高,为541.77 gC·m~(-2)·a~(-1),下游次之,为482.10 gC·m~(-2)·a~(-1),中游年平均NPP排在最后,为462.46 gC·m~(-2)·a~(-1),三个区域在16年的时间跨度上总体都是呈上升趋势;对年均NPP从小到大分类,其中NPP在400~600 gC·m~(-2)·a~(-1)这个范围占比最大,平均为48.7%,NPP小于400 gC·m~(-2)·a~(-1)和NPP大于600 gC·m~(-2)·a~(-1)的面积所占比例基本相差不大,分别为27.0%和25.3%;从整个流域来看,大部分地区植被的NPP值是增长的,NPP值增加的区域面积加起来占总面积的80%,下降的区域只占到20%;植被NPP与降水量、气温、湿度具有一定的线性正相关关系.     

基于MODIS17A3的呼伦贝尔沙地植被NPP时空格局变化分析

植被净初级生产力(NPP)可以直接反映植物的生产能力.为研究呼伦贝尔沙地植被NPP时空变化情况,本文选用NPP产品数据MODIS17A3进行处理后,结合气温降水以及经济产业数据,利用简单差值法、一元线性回归分析的方法对该地区沙地植被NPP的时空变化以及驱动力进行了分析.经过研究发现:(1)呼伦贝尔沙地地区植被NPP呈现由东向西递减的趋势;(2)植被NPP增长最大的是鄂温克族自治旗与新巴尔虎右旗,而满洲里与海拉尔地区呈现负增长比重较大,分别占到12.2%、6.33%;(3)15年以来该地区总体NPP呈现增长模式,生态恢复比较好.     

气候变化对漳州市植被生态影响分析

植被净第一性生产力(NPP)是反映植被生态的重要因子,通过NPP对区域植被生态变化进行研究具有重要的意义.基于气候影响的自然植被的净第一性生产力模型,应用线性倾向值估计等统计方法,分析1981-2016年漳州市气候变化及NPP变化特征.结果表明,漳州市气候呈现气温显著升高、降水增多的暖湿化倾向,全市NPP年平均值随年际变化,并呈微略增加趋势,NPP年际总体波动幅度小,植被生产力较为稳定.漳州市NPP分布具有明显的县域差别,漳州南部县(东山、诏安)为NPP最小值区,而中部县(南靖、平和、云霄县)为最大值区,内陆山区县NPP值总体较沿海县市大.NNP空间分布呈现由东南部向西北部、南部向北部递增的分布态势,但各县市各年代NPP值都保持较为稳定,有利于漳州市良好生态的维持.漳州市降水与其NPP呈显著正相关,降水对NPP有着重要影响作用.     

基于GIS、RS和CASA模型的深圳市逐月NPP估算及其变化特征研究

植被净初级生产力(NPP)及其对气候变化的响应是研究全球碳循环的重要内容之一.本文在GIS的支持下,采用深圳市2004年和2008年的MODISNDVI时间序列数据和逐月气象数据,利用CASA模型估算了逐月的NPP值,对比分析了其空间分布特征,探讨了极端暴雨天气对NPP月变化特征的影响及其气候因子对NPP的影响.结果表明:深圳市的NPP呈现显著的季节性变化;在出现极端暴雨天气的2008年6月,NPP值急剧下降,年内NPP逐月变化时间序列被延后;月均气温显著影响深圳市NPP的变化,而当极端暴雨天气出现时,太阳辐射对NPP的影响比降水量的影响更大.     

呼伦贝尔草地生产力模型适用性及对气候变化响应分析

本文利用研究区草地植被净初级生产力(NPP)实地测定资料(2008~2013年)和气象资料(1961~2013年),分析验证了Miami模型、Thornthwaite Memorial模型和周广胜综合模型对研究区草地的适用性,同时建立了草地NPP与气温和降水量间的回归预测模型,对研究区草地NPP对气候变化的响应进行预测分析.结果表明:研究区气候变化呈暖干化趋势.Miami模型、Thornthwaite Memorial模型以及周广胜综合模型对研究区气候生产力模拟适用性较差,使用时需要进行修正.降水是影响呼伦贝尔草地NPP的主要限制因子,而温度对NPP的影响相对较小.50多年来,研究区草地NPP总体呈下降趋势,下降速率为11.04 g·m-2·10a-1.     

基于CASA模型和SEVI指数的福建省植被NPP遥感估算与分析

植被净初级生产力(NPP)是评估陆地生态系统碳汇和调节过程的重要指标,但遥感影像上崎岖地形造成的光学辐射传输畸变会降低植被NPP估算精度.为了消除地形对山区植被NPP模型估算的影响,以福建省为研究区,利用阴影消除植被指数(SEVI)改进CASA模型中的植被光合有效辐射吸收比率因子(FPAR)计算模型,进行福建省2005...     

基于MODIS的广西植被NPP时空分异及驱动力分析

为探索广西植被净初级生产力(net primary productivity,NPP)变化规律及驱动因子,利用遥感数据、土壤数据和海拔高程数据,运用统计学分析方法,对比分析不同城市、土壤、海拔高度的植被NPP变化。结果表明:(1)2000—2015年广西植被NPP值(以碳累积量计)在578.51～870.48 g·m~(-2)·a~(-1)波动变化,总体呈下降趋势。梧州、防城港的植被NPP值较高。(2)广西6.45%区域的植被NPP处于重度变异状态,65.25%区域的植被NPP处于中度变异,28.30%区域的植被NPP处于轻度变异状态。(3)植被NPP对气温降水的变化响应不够显著。(4)红壤、石灰土、粗骨土地区的植被NPP呈下降趋势,而砖红壤地区的植被NPP呈增加趋势。(5)不同海拔高度的植被NPP差异较大,总体变化呈"增加-下降-增加-下降"的趋势。     

基于CASA模型的武汉市生态系统净初级生产力(NPP)遥感估算

为研究快速城市化建设地区生态系统的NPP空间分布特征,基于LANDSAT-ETM遥感影像数据和3R空间分析技术,对CASA模型进行适当改进,构建武汉市NPP估算模型,估算武汉市2013年生态系统的净初级生产力.结果表明:1)武汉市生态系统NPP总量为154.22×10~(10)g C,总体呈现远城区远高于主城区的空间分布特征,土地利用类型中林地对NPP的贡献相对最大,其中7个主城区的NPP总量为5.38×10~(10)g C,6个远城区的NPP总量为141.64×10~(10)g C,约为主城区的26倍;2)全市13个区中,NPP总量权重排名前6的区均为远城区,黄陂区植被净生产量最高(45.46×10~(10)g C),江汉区最低(0.32×10~(10)g C),两者相差142倍之多;3)单位面积NPP空间上呈现中央区域低、四周区域高的雷达辐射状的分布特征,全市生态系统单位面积平均NPP为179.76×106g C/km2,其中主城区单位面积NPP约为56×106g C/km2,远城区单位面积NPP约为186×106g C/km2,约为主城区的3.3倍;4)武汉市13个区的单位面积NPP按照大小进行排列,黄陂区蔡甸区新洲区东西湖区江夏区汉南区武昌区江汉区青山区硚口区江岸区汉阳区洪山区.研究建议武汉市远城区应注重生态农业、生态旅游业发展,主城区应高度重视生态环境保护,采取立体化、多维度的方式修建生态空间,加大生态修复力度,逐步提高城市绿地占比,为市民创造更为舒适的居住环境.     

北京市门头沟区2003-2014年植被初级生产力时空变化

采用CASA模型和30 m分辨率Landsat数据生成了门头沟区2003—2014年的植被净初级生产力(NPP)产品,分析了门头沟区NPP的空间分异特征,基于MODIS年NPP产品分析了门头沟区2003—2014年NPP的年际变化特征,基于MODIS植被总初级生产力(GPP)时间序列数据分析了门头沟区典型年份的年内GPP变化特征.结果表明:2003—2014年门头沟区NPP受地形及人为因素影响,低值区主要沿河流谷地及东部河流出山口处分布,在整体区域上呈现四周高、中间低的特征;自2005年以来年际NPP总体平稳,没有明显的增加或减少趋势;GPP年内波动明显,5—9月GPP/NPP的差异对不同年份间GPP/NPP差异的贡献最大.     

中国不同植被类型净初级生产力变化特征

收集、统计了1993—2011年所发表的98篇涉及我国不同植被NPP数据(模型模拟估算值和实测值)的代表性论文.分析了我国不同植被类型NPP研究结果及其变化和空间分布特征.结果表明:1)模型模拟和实测NPP值都较高的植被类型有热带雨林、季雨林,常绿阔叶林,常绿针叶林、混交林和落叶阔叶林;2)模型模拟的植被NPP值空间分布规律基本表现为从东南沿海地区依次向西北内陆递减;3)在模型模拟与实测NPP值所共有的9种植被类型中,除耕地、灌丛和草地的模型模拟NPP值略大于实测值,其余6种植被类型均小于实测值;4)不同模型对同一种植被类型的模拟结果之间表现出了极大的差异;5)模型模拟平均值与实测值之间的差异相对较小,采用已提出的模型模拟平均值来估算我国不同植被的NPP是基本可行的.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with