A modified trapezoid framework model for partitioning regional evapotranspiration     

Jinhui Jeanne Huang  Han Chen  Tingting Li  Edward McBean  Vijay P. Singh 《水文研究》2020,34(25):5026-5042

While evapotranspiration (ET) is normally measured as one hydrologic component, evaporation (E), and transpiration (T) result from different physical-biological processes. Using a two-source model, a trapezoid framework has been widely applied in recent years. The key to applying the trapezoid framework model is the determination of the dry/wet boundaries of the land surface temperature-fractional vegetation coverage trapezoid (LST-f_c). Although algorithms have been developed to characterize the two boundaries, there remains a significant uncertainty near the wet boundary which scatters in a discrete and uneven manner. It is therefore difficult to precisely locate the wet boundary. To address this problem, a Wet Boundary Algorithm (WBA) was developed in this study with the algorithm applied in the region of Huang-Huai-Hai plain of China, using the Pixel Component Arranging and Comparing Algorithm (PCACA) to retrieve ET from MODerate-resolution Imaging Spectroradiometer (MODIS) Data. The eddy covariance (EC) measurements from Yucheng station was used to verify the modified model where the root mean square error (RMSE) of 17.8 W/m², Bias of −7.2 W/m² for latent heat flux (LE) simulation in 28 cloudless test days. The ratio of transpiration to evapotranspiration (T/ET) varied between 0.48 and 0.81 over the Huang-Huai-Hai plain. The spatial and temporal distribution of ET revealed that agriculture practices have a significant influence on the hydrological cycle, where crop growth promotes the magnitude of ET. Likewise, harvesting activities significantly reduce ET. The proposed WBA algorithm significantly reduces the uncertainty of the trapezoid ET model caused by wet edge positioning. The analysis of the impact of agricultural activities on ET provide a better understanding how human activities change the hydrological cycle at regional scales.  相似文献   

FFT‐based bounds on the permeability of complex microstructures     

F. Bignonnet  L. Dormieux 《国际地质力学数值与分析法杂志》2014,38(16):1707-1723

A numerical scheme for the computation of the permeability of complex microstructures is presented. As a darcean counterpart of the FFT‐based scheme in elasticity, the method is designed to be directly coupled with 3D imaging techniques of porous samples, without meshing or definition of an equivalent pore network. The method relies on the variational principle of Hashin and Shtrikman, which ensures a rigorous upper bound status to the estimated permeabilities and provides an energetically consistent rule for heterogeneous voxels comprising both the solid and fluid phases. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

A spatiotemporal mining framework for abnormal association patterns in marine environments with a time series of remote sensing images     

《International Journal of Applied Earth Observation and Geoinformation》2015

A spatiotemporal mining framework is a novel tool for the analysis of marine association patterns using multiple remote sensing images. From data pretreatment, to algorithm design, to association rule mining and pattern visualization, this paper outlines a spatiotemporal mining framework for abnormal association patterns in marine environments, including pixel-based and object-based mining models. Within this framework, some key issues are also addressed. In the data pretreatment phase, we propose an algorithm for extracting abnormal objects or pixels over marine surfaces, and construct a mining transaction table with object-based and pixel-based strategies. In the mining algorithm phase, a recursion method to construct a direct association pattern tree is addressed with an asymmetric mutual information table, and a recursive mining algorithm to find frequent items. In the knowledge visualization phase, a “Dimension–Attributes” visualization framework is used to display spatiotemporal association patterns. Finally, spatiotemporal association patterns for marine environmental parameters in the Pacific Ocean are identified, and the results prove the effectiveness and the efficiency of the proposed mining framework.  相似文献   

海南国际旅游岛数字地理空间框架建设与应用     

刘璐  卢金莎 《测绘与空间地理信息》2015,(2):165-167

数字城市和数字省区相互之间既有明确的层次关系,同时共性中又有着个性.本文首先简单介绍了海南国际旅游岛数字地理空间框架建设的总体架构,重点阐述框架建设项目的主要建设情况以及推广应用情况.  相似文献   

城市群空间性质的透视与中原城市群的构建   总被引：5，自引：2，他引：3  

苗长虹  胡志强 《地理科学进展》2015,34(3)

区域是地理学理论建构的核心论题。在地理学发展进程中,对区域的论争主要围绕地域空间、网络空间和空间的生产展开,并呈现出由单一维度向多维度转变的趋势。城市群空间是一种新的区域空间,具有地域空间、网络空间、空间的生产与建构等多重属性。空间具有社会性和历史建构性,对空间的关注正从空间中的生产向空间本身的生产转变。空间生产离不开权力运作,空间是话语建构的产物。中国对城市群概念的认知和范围界定的争议源于区域概念的多重属性。以中原城市群的构建过程为实证案例,提出了中原城市群构建过程中存在的问题,围绕"城市群究竟是什么?"这一核心论题,透视了城市群空间的多重性质。最后,针对单一维度的局限性,提出了认知和界定城市群的多维度框架,包括领土(Territory)、地方(Place)、尺度(Scale)、网络(Network)和功能(Function)五个方面,并指出了今后进行城市群研究需要关注的理论重点。  相似文献   

电子政务顶层设计方法研究   总被引：1，自引：0，他引：1  

金江军 《国土资源信息化》2011,(4):3-5,36

人们对电子政务顶层设计的重要性已经达成广泛共识。本文首先介绍了美国、英国、德国、新加坡的电子政务顶层设计进展,然后设计了电子政务总体框架,该框架由业务架构、服务架构、应用架构、信息架构、技术架构、管理架构六个部分构成。最后提出了电子政务顶层设计推进策略,指出了顶层设计与规划的区别。  相似文献   

物联网中的地理信息系统     

易雄鹰  任应超  李晓锋  唐建智 《测绘软科学研究》2011,9(1):48-51

物联网的建设为地理信息系统提供了巨大的发展机遇。本文分别从支撑框架、核心技术和应用领域等几个方面,研究了在物联网建设中引入地理信息系统相关理论和技术的必要性和可行性,并指出了地理信息系统应用于物联网环境需要解决的关键问题。  相似文献   

北京市基础地理信息框架数据初探   总被引：1，自引：1，他引：0  

王旭辉  张保钢 《北京测绘》2011,(3):1-3

结合北京市基础地理信息产品应用现状,提出北京市基础地理信息框架数据概念,开展基于框架数据的制图与可视化表达技术及数据更新机制研究,生产满足不同用户需求的地理信息产品,促进基础地理信息在各行业更加深入应用,为提高北京市地理信息公共服务水平奠定数据基础。  相似文献   

"应急一张图"与应急信息资源整合框架研究——以重庆市为例     

李莉  丁忆  张红文 《测绘科学》2011,36(1):125-127

本文分析了应急信息资源整合的意义和重庆市应急信息资源的基本情况,介绍了重庆市地理空间信息内容及要素代码标准和重庆市应急数据资源分类与编码规范,对应急信息资源整合模式进行了研究,分析了应急资源整合关键技术,并以重庆市为例进行了应用分析.  相似文献   

塔里木盆地东南缘阿克塔什塔格地区古元古代精细年代格架的确定及其地质意义     

辛后田  赵凤清  罗照华  刘永顺  万渝生  王树庆 《地质学报》2011,85(12):1977-1993

塔里木盆地东南缘的阿克塔什塔格地区,基底变质杂岩中含有较多的古元古代变质侵入体及敦煌岩群孔兹岩系.变质侵入体规模一般较小,它们以岩体特征明显、与米兰岩群的侵入接触界线清晰、钠质混合岩化不发育、角闪岩相变质等特征区别新太古代TTG岩系.其中,以岩体形式较大规模出露的有闪长质片麻岩、片麻状石英闪长岩、角闪石英正长岩、碳酸岩...  相似文献