Stormflow threshold behaviour in a subtropical mountainous headwater catchment during forest recovery period     

Lezhang Wei  Zhijun Qiu  Guangyi Zhou  Tsuyoshi Kinouchi  Yu Liu 《水文研究》2020,34(8):1728-1740

Forest ecohydrological feedbacks complicate the threshold behaviour of stormflow response to precipitation or wetting conditions on a long-term scale (e.g. several years). In this study, the threshold behaviours in an evergreen-deciduous mixed forested headwater catchment in southern China were examined during 2009–2015, when damaged vegetation was recovering after the great 2008 Chinese ice and snowstorm. The non-uniqueness of the thresholds and the slow and rapid responses of stormflow at the outlet of the catchment in different hydro-climate datasets with different maximum values of gross precipitation (P) and sums of precipitation and antecedent soil moisture index (P + ASI) were assessed. The thresholds of P and P + ASI required to trigger stormflows (i.e. ‘generation thresholds’) and the transition from slow to rapid responses of stormflow (i.e. ‘rise thresholds’) were compared both seasonally and annually. The results indicated significant differences in the analysed datasets, highlighting the need to compare thresholds with care to avoid misinterpretation. Seasonal variations in threshold behaviours in the catchment suggested that vegetation canopy interception contributed to higher rise thresholds, and wetter conditions resulted in higher runoff sensitivity to precipitation during the growing and rainy seasons. Furthermore, the generation thresholds were higher in the dormant season, possibly due to drier soil moisture conditions in the near-channel areas. During the vegetation recovery period, the annual generation thresholds increased, however the rise thresholds did not exhibit a similar trend. The rapid stormflow response above the threshold decreased, possibly due to transpiration and interception of the recovered vegetation. However, the slow stormflow response to small rainfall events below the thresholds was higher in wetter years but lower in drier years, suggesting that the total water input dominated the stormflow response during small rainfall events. In conclusion, the seasonal and annual variations in threshold behaviours highlight that vegetation recovery and hydro-climatic conditions had a notable impact on the stormflow response.  相似文献   

Effects of intensive aquifers exploitation on groundwater salinity in coastal wetlands     

Malva Mancuso  Lucía Santucci  Eleonora Carol 《水文研究》2020,34(11):2313-2323

The coastal plain of the Río de la Plata constitutes a large wetland which develops on the right margin of the river estuary. Anthropic activities such as intensive exploitation of groundwater carried out in the vicinity of the wetland can modify the natural hydrological regime. The aim of this work is to asses the effects of intensive aquifer exploitation in coastal wetlands using hydrogeological models. Such models allow to evaluate changes in the environmental conditions of wetland at regional level. The hydrogeological model exposed in this work shows how the intensive groundwater exploitation affects the wetland area, generating important variations both in the groundwater flows and in the salinity of the groundwater. Identification of these modifications to the environment is important to generate guidelines leading to minimize these affectations.  相似文献   

一种云端一体化的土地督察遥感监测方法     

孙久虎 《测绘通报》2020,(3):129-133

针对目前土地遥感监测工作中存在的监测频次低和数据现势性差等问题，通过统筹获取国产卫星影像数据提升监测频次，设计了多源遥感影像的空间网格组织和调度方法，改变传统的影像切片发布模式，建立实时影像服务方法，大幅提升了土地督察遥感监测时效。通过在国家土地督察济南局试点应用，研发了云端一体化的土地督察遥感监测服务平台，实践证明基于空间网格的影像组织管理效率优于传统金字塔切片管理模式，有效支撑了违法用地、永久基本农田保护和城市开发边界突破等监测预警，应用成效显著。  相似文献   

基于自然间断点分级法的土地利用数据网格化分析   总被引：4，自引：0，他引：4  

李乃强  徐贵阳 《测绘通报》2020,(4):106

土地利用在自然资源统一管理中扮演着重要角色，面对不同区域和年份的数据，统一分析比对口径尤为重要，同时也应反映出相互之间的差异。本文以宜兴市2009年和2017年土地利用现状数据为数据源，首先使用统一的分类标准提取用地类型中的3大类，通过不同大小的单元划分尝试和结果分析，发现适用于该数据的网格尺度大小；然后基于自然间断点分级法进行分级范围划定，对宜兴市三类用地类型的分布和变化趋势进行综合分析，较为真实地反映了宜兴市用地情况；最后通过选用合适的空间尺度和分级范围划定方法，进而构建一个兼具操作性和科学性的土地利用数据网格化方法，为自然资源部门统筹管理和综合治理提供依据。  相似文献   

基于自然资源管理的新型基础测绘研究     

穆增光  刘慧慧 《北京测绘》2020,(2):151-154

新一轮的职能改革赋予自然资源部门新的职责,文章在分析了现有自然资源业务数据和基础测绘数据的基础上结合自然资源管理需求,提出了新型基础测绘的相关技术要求、应用方向和地理实体数据的技术路线,为新型基础测绘的开展提供了有益探索,为基础测绘服务自然资源管理提供了理论依据。  相似文献   

基于GIS的石家庄市雾霾分析     

苏亚聪  史娟  徐爽 《北京测绘》2020,(2):233-237

为了得出雾霾气象成因机制、影响因素和时空分布特征,以石家庄市区与郊县为研究区域,将2013年9月至2016年12月石家庄市各市区、郊县的PM2.5历史监测数据中的有效数据进行了数据分析处理得到雾霾浓度数据,还有温度、降水、风速、地形和人口密度等数据,运用GIS分析的方法,模拟绘制石家庄雾霾的时空分布图、雾霾与各影响因子的专题对比图,得到雾霾形成机制的因子、雾霾的时空分布规律、雾霾季节变化特征、雾霾与地形间的关系等;运用数据分析软件OriginPro8.SR3分析雾霾浓度与风速数据、降雨数据、温度数据间的相关性。  相似文献   

FY-3D/MERSI-II全球火点监测产品及其应用   总被引：1，自引：0，他引：1  

郑伟  陈洁  闫华  刘诚  唐世浩 《遥感学报》2020,24(5):521-530

FY-3D/MERSI-II全球火点监测产品主要包括全球范围内的火点位置、亚像元火点面积和火点强度等信息,可用于实时监测全球范围的森林草原火灾、秸秆焚烧等生物质燃烧状况。火点判识算法主要根据中红外通道对高温热源的敏感特性,即含有火点的中红外通道像元辐亮度和亮温较远红外通道的辐亮度和亮温偏高,同时较周边非火点的中红外像元偏高,建立合适的阈值可探测含有火点的像元。亚像元火点面积估算主要使用中红外单通道估算,根据亚像元火点面积估算结果对火点强度进行分级,不同的级别表示不同程度的火点辐射强度。基于全球火点自动判识结果,每日生成0.01°分辨率的卫星遥感日全球火点产品,每月生产0.25°×0.25°格点的全球月火点密度图。在利用FY-3D/MERSI-II火点产品开展的全球火点监测应用中,对多起全球重大野火事件进行了监测,为防灾减灾、全球气候变化研究、生态环境保护等方面提供卫星遥感信息支持。  相似文献   

基于GIS的高校物流代理点选址研究     

贾艳红  文帆  钟英 《测绘与空间地理信息》2020,(3):19-21,25

随着电子商务在社会生活中的广泛兴起,校园物流代理点也随之产生;物流代理点在很大程度上方便了师生快递领取,但由于高校物流代理点选址普遍存在随意性和不合理性,导致师生快递领取时浪费过多时间和精力。针对此问题,本研究结合GIS空间分析技术,通过对广西师范大学雁山校区学生宿舍、教学楼、食堂和道路分布数据的分析,利用缓冲区分析和叠置分析优选出物流代理点最佳分布区域,并对校园中现有的物流代理点分布合理性做出评价,进而给出合理的校园物流代理点选址区域建议,旨在为学校物流代理点科学选址及改善和提升校园人文品质提供合理建议,同时为物流企业规划选址及GIS空间分析应用提供参考。  相似文献   

Exploration prospects of oil and gas in the Northwestern part of the Offshore Indus Basin,Pakistan     

《China Geology》2020,3(4):633-642

Oil and gas resources are short in Pakistan and no commercially viable oil and gas sources have been yet discovered in its offshore areas up to now. In this study, the onshore-offshore stratigraphic correlation and seismic data interpretation were conducted to determine the oil and gas resource potential in the Offshore Indus Basin, Pakistan. Based on the comprehensive analysis of the results and previous data, it is considered that the Cretaceous may widely exist and three sets of source rocks may be developed in the Offshore Indus Basin. The presence of Miocene mudstones has been proven by drilling to be high-quality source rocks, while the Cretaceous and Paleocene–Eocene mudstones are potential source rocks. Tectonic-lithologic traps are developed in the northwestern part of the basin affected by the strike-slip faults along Murray Ridge. Furthermore, the Cretaceous and Paleocene–Eocene source rocks are thick and are slightly affected by volcanic activities. Therefore, it can be inferred that the northwestern part of Offshore Indus Basin enjoys good prospects of oil and gas resources.  相似文献   

南海开放共享航次关键科学问题的思考——从多尺度海洋动力学角度出发     

杜岩  陈举  经志友  王祥鹏  陈更新  徐驰  储小青  陈植武  徐杰  施震  唐世林  何云开  梁韵  施平 《热带海洋学报》2020,39(6):1-17

南海是西太平洋最大的边缘海, 通过一系列的海峡与西太平洋和印度洋相联通, 其不同时空尺度的海洋环流动力过程及其生态环境效应是南海区域海洋学研究的重要内容。自20世纪50年代末全国第一次海洋普查开始, 我国对海洋调查的支持力度不断加大, 以科学考察船为代表的海洋科学观测平台建设不断加强; 进入新千年以来, 国内海洋科考船依托的各主要研究所和院校本着开放的理念, 先后组织多单位联合进行海上观测。尤其是最近10年, 国家自然科学基金委员会支持实施了船时共享航次计划, 进一步促进了国内海洋界的交流和合作, 南海区域海洋学的相关研究取得了很多重要的成果。从多尺度环流动力学的角度出发, 本文简要回顾了南海海洋观测的发展历程, 并初步总结了近些年来南海关键科学问题的研究进展, 包括南海和西太平洋的水体交换过程、南海中小尺度过程、多尺度相互作用及其生态环境效应等; 并且在现有的研究基础上, 对未来南海的观测和科学问题提出若干思考与展望。  相似文献