【摘 要】
：
With the implementation of the Grain for Green Project,vegetation cover has expe-rienced great changes throughout the Loess Plateau (LP).These changes substantially in-fluence the intensity of evapotranspiration (ET),thereby regulating the local microclim
【机 构】
：
School of Geography,South China Normal University,Guangzhou 510631,China;School of Geography and Tou
论文部分内容阅读
With the implementation of the Grain for Green Project,vegetation cover has expe-rienced great changes throughout the Loess Plateau (LP).These changes substantially in-fluence the intensity of evapotranspiration (ET),thereby regulating the local microclimate.In this study,we estimated ET based on the Penman-Monteith (PM) method and Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model and quantitatively estimated the mass of water vapor and heat absorption on the LP.We analyzed the regulatory effect of vegetation resto-ration on local microclimate from 2000 to 2015 and found the following:(1) Both the leaf area index (LAI) value and actual ET increased significantly across the region during the study period,and there was a significant positive correlation between them in spatial patterns and temporal trends.(2) Vegetation regulated the local microclimate through ET,which increased the absolute humidity by 2.76-3.29 g m-3,increased the relative humidity by 15.43％-19.31％and reduced the temperature by 5.38-6.43℃ per day from June to September.(3) The cooling and humidifying effects of vegetation were also affected by the temperature on the LP.(4) Correlation analysis showed that LAI was significantly correlated with temperature at the monthly scale,and the response of vegetation growth to temperature had no time-lag effect.This paper presents new insights into quantitatively assessing the regulatory effect of vege-tation on the local microclimate through ET and helps to objectively evaluate the ecological effects of the Grain for Green Project on the LP.
其他文献
对大规模三维模型的Web传输与可视化渲染进行了研究.基于Cesium JS框架搭建网页三维地形场景,实现了glTF和3D Tiles两种模型的三维可视化;对不同层级的模型加载进行了对比;并从文件结构、数据存储方式等方面对两种三维模型进行了解析.结果 表明,两种模型在网络传输和渲染方面具有很大优势,可在复杂的三维地理信息可视化研究中发挥作用.
为解决轨道工程中工程测量业务计算复杂、内业滞后等实际问题,设计并实现了城市轨道测量信息系统.系统运用J2EE、Android和数据库技术,将Web主站端系统与移动端App相结合,满足了业务管理流程化、外业数据采集智能化、测量人员和仪器调配信息化等用户对城市轨道工程测量的需求.在实际应用中,系统明显提高了测量工作的效率,提升了工程测量业务的信息化管理水平,对工程施工单位项目建设具有一定的实用价值.
针对传统既有铁路曲线重构方式图形化交互程度低,无法实现既有铁路图形和属性数据的统一管理,从而导致曲线重构步骤繁琐的问题,利用GIS建立了既有铁路曲线重构系统,实现了既有铁路图形和属性数据的一体化管理、数据查询以及既有铁路正交最小二乘曲线重构.计算实例表明,该图形化作业方式人机交互方便、操作简单、效率高,能快速实现既有铁路曲线重构,重构曲线的拨正量能满足精度要求,拟合结果更加接近工务台账,具有很好的用户体验.
基于GNSS、全站仪、倒垂数据,提出了一套适用于水电站二维测量基准建立与一致性维护的理论和方法.该方法首先将GNSS基线和全站仪边角观测值进行联合处理,再采用粗差探测、粗差剔除和方差分量估计等方法,按照一点一方向的模式进行边角网平差,最后对平差后的点位坐标进行精度评定.以大渡河某水电站监测数据为例,验证了该方法的可靠性和稳定性.
对利用高精度全站仪、自动水位计等多种监测方法开展湖北国际物流核心枢纽花马湖水系综合治理工程施工以及运营期安全监测工作进行了研究;详细介绍了基坑、连通渠等不同监测对象采用的监测方法,并对监测结果进行了分析,实现了对项目安全施工的监测预警,消除了可能产生的安全隐患,能为同类项目安全监测提供监测经验和参考依据.
随着时代发展和技术演进,地图学的内容不断丰富和演化.《地图学》是很多地学相关专业的专业基础课,但在教学过程中仍存在一些问题,结合多年教学经验,从教学内容、教学方法、实践应用等方面进行了一些思索与探讨.
国内Cesium三维地图引擎研究方兴未艾,但在地质公园领域的应用却寥寥无几.基于Cesium技术进行开发研究,建立了三维地质公园导览系统.以3D Tiles格式的倾斜数据为基础,融合了地质公园二维专题数据;通过调用Cesium平台的相关接口,实现了地质公园的二三维可视化展示、空间量测和空间查询等功能.系统支持加载海量倾斜数据,兼容性强、浏览速度快,为在线浏览三维地质公园提供了可行的技术方法.
Mountainous landscapes are particularly vulnerable and sensitive to climate change and human activities,and a clear understanding of how ecosystem services (ES) and their relationships continuously change over time,across space,and along altitude is there
The glaciers in the Sanjiangyuan Nature Reserve of China (SNRC) are a significant water resource for the Yangtze,Yellow,and Mekong rivers.Based on Landsat Thematic Mapper(TM)/Operational Land Imager (OLI) images acquired in 2000,2010,and 2018,the outlines
目前各高校在道路勘测设计实践环节多采用基于团队作业的考核方法,即小组打分法.受限于教学资源,教师利用该方法难以根据学生的个人能力给出公正客观的成绩.为避免片面、主观的考评现状,发挥团队作业的教学优势,提出了批量量化的考核方法,并详细介绍了其设计思路,以期在师生比偏小的现状下提高实践教学的质量、增加学生的积极性和参与度、为高校其他课程的实习考核提供参考.