作物胁迫无人机遥感监测研究评述   总被引：1，自引：0，他引：1  

黄耀欢  李中华  朱海涛 《地球信息科学学报》2019,21(4):512-523

作物胁迫是全球农业发展的一个重要制约因素,实现快速、大范围、实时的作物胁迫监测对于农业生产具有重要意义。传统的作物胁迫监测方式,如田间调查、理化检测和卫星遥感监测总是受到各种田间条件或大气条件的制约。随着无人机和各种轻量化传感器的快速发展,其凭借高频、迅捷等优势为各种作物胁迫监测提供了一套全新的解决方案。本文在介绍了目前主流的多种无人机和传感器的基础上,首先对目前无人机遥感用于作物监测的主要胁迫类型进行了梳理,然后重点阐述了基于光谱成像和热红外传感器进行作物胁迫无人机遥感监测的应用和技术方法,最后提出了作物胁迫无人机遥感监测尚需解决的关键问题,并展望了未来无人机遥感用于作物胁迫监测的前景。  相似文献   

我国红黏土物理力学性能研究现状及展望     

邓绍云 《岩土工程技术》2020,(1):43-47

采用文献综述研究方法,梳理了红黏土研究成果并进行了评述,对红黏土的物理力学性质进行了归纳和总结,对红黏土的性能改良研究成果进行了汇总,指出红黏土的物理力学性能的差异性根源在于微观结构的个性差异存在,红黏土性能改良的困难在于红黏土的水敏性和热敏性,红黏土性能改良的关键在于控制其含水率。最后指出了研究不足在于普适性理论和知识体系没有构建,改良方法和技术探究应该加强,展望了红黏土性能改良的物理—化学—生物耦合作用的机理及复合技术开发和应用的研究。  相似文献   

全球尺度水文模型： 机遇、 挑战与展望   总被引：4，自引：2，他引：2  

高红凯  赵舫 《冰川冻土》2020,42(1):224-233

水循环发生在全球尺度， 局地和流域水问题的解决也往往需要全球视角， 因此全球尺度水文模型应运而生。从科学意义和国家需求等多个视角， 论述了全球水文学研究的意义和巨大的发展潜力， 系统总结了现有全球尺度水文模型发展现状， 剖析了十余个主流全球尺度水文模型的结构和功能， 以及全球水文-气象-地理信息等全球模型所需数据集。进而分析了现有全球尺度水文模型存在的主要问题和挑战， 为进一步完善模型提供参考。最终分别从模型机理、 大数据、 新技术、 多部门模型耦合等几个方面， 探讨了全球尺度水文模型未来发展的重要方向。  相似文献   

Significance of post‐peak metamorphic reaction microstructures in the ultrahigh temperature Eastern Ghats Province,India          下载免费PDF全文

David E. Kelsey  Laura J. Morrissey  Martin Hand  Chris Clark  Renee Tamblyn  Adrian A. Gaehl  Sarah Marshall 《Journal of Metamorphic Geology》2017,35(9):1081-1109

Ultrahigh temperature (UHT) granulites in the Eastern Ghats Province (EGP) have a complex P–T–t history. We review the P–T histories of UHT metamorphism in the EGP and use that as a framework for investigating the P–T–t history of Mg–Al‐rich granulites from Anakapalle, with the express purpose of trying to reconcile the down‐pressure‐dominated P–T path with other UHT localities in the EGP. Mafic granulite that is host to Mg–Al‐rich metasedimentary granulites at Anakapalle has a protolith age of c. 1,580 Ma. Mg–Al‐rich metasedimentary granulites within the mafic granulite at Anakapalle were metamorphosed at UHT conditions during tectonism at 960–875 Ma, meaning that the UHT metamorphism was not the result of contact metamorphism from emplacement of the host mafic rock. Reworking occurred during the Pan‐African (c. 600–500 Ma) event, and is interpreted to have produced hydrous assemblages that overprint the post‐peak high‐T retrograde assemblages. In contrast to rocks elsewhere in the EGP that developed post‐peak cordierite, the metasedimentary granulites at Anakapalle developed post‐peak, generation ‘2’ reaction products that are cordierite‐absent and nominally anhydrous. Therefore, rocks at Anakapalle offer the unique opportunity to quantify the pressure drop that occurred during so‐called M2 that affected the EGP. We argue that M2 is either a continuation of M1 and that the overall P–T path shape is a complex counter‐clockwise loop, or that M1 is an up‐temperature counter‐clockwise deviation superimposed on the M2 path. Therefore, rather than the rocks at Anakapalle having a metamorphic history that is apparently anomalous from the rest of the EGP, we interpret that other previously studied localities in the EGP record a different part of the same P–T path history as Anakapalle, but do not preserve a significant record of pressure decrease. This is due either to the inability of refractory rocks to extensively react to produce a rich mineralogical record of pressure decrease, or because the earlier high‐P part of the rocks history was erased by the M1 loop. Irrespective of the specific scenario, models for the tectonic evolution of the EGP must take the substantial pressure decrease during M2 into account, as it is probable the P–T record at Anakapalle is a reflection of tectonics affecting the entire province.  相似文献   

多年冻土区石油污染物迁移过程研究回顾与展望   总被引：3，自引：1，他引：2  

李国玉  马巍  李兴柏  穆彦虎  毛云程 《冰川冻土》2011,33(4):947-952

多年冻土区泄漏石油污染物会引起严重的环境和工程问题．通过对国内外石油污染物迁移过程、迁移机理、迁移模型、影响因素等研究进行回顾,基于国内外冻土区石油污染的研究进展和社会经济发展要求,提出了多年冻土区石油污染物可能引起的环境与工程问题,并对相关的科学问题进行展望,期望对以后研究工作有所指导并逐渐得到解决．  相似文献   

地下水温度示踪理论与方法研究进展   总被引：6，自引：0，他引：6  

吴志伟  宋汉周 《水科学进展》2011,22(5):733-740

对地下水温度示踪理论与方法的相关研究做了评述,介绍了当前地质体中温度场与渗流场耦合作用模型、数值模拟技术和渗流参数反演方法,并从温度示踪方法的两个主要应用领域:地表水与地下水交换和工程地下水渗漏探测(以堤坝为例),说明地下水温度示踪的应用研究.在地质体中温度场与渗流场耦合模型方面,裂隙介质、非饱和带、复杂边界条件和非D...  相似文献   

“广西型花岗岩"的地球动力学意义——答汪洋(2015)的质疑     

张旗 《岩石矿物学杂志》2015,34(3):440-444

汪洋撰文批评笔者提出的"广西型花岗岩"没有任何意义,认为花岗岩类的全岩Sr、Yb含量不是指示花岗质岩浆起源压力的可靠指标,以Sr-Yb为基础的花岗岩分类没有地球动力学意义。笔者认为,花岗岩可以形成于不同的压力条件下不是笔者的发明,国外早有论述,例如Defant和Drummond(1990)关于埃达克岩和岛弧ADR的认识。汪洋认为,花岗质岩浆可以形成于下地壳部位,也可以形成于中地壳深度,还认为基性岩浆分离结晶可以形成花岗质岩浆,这都是笔者不赞同的,因为缺乏野外证据。广西型花岗岩以富Sr和Yb为特征,指示在相图上位于石榴石出现线之下和斜长石消失线之上,暗示残留相既无石榴石也无斜长石。汪洋引用了不同地区不同作者对广西型花岗岩成因的不同见解,与笔者关于广西型的概念没有任何关系,也不能据此否定笔者关于广西型花岗岩的认识。  相似文献   

Arctic sea ice and Eurasian climate: A review   总被引：12，自引：0，他引：12  

GAO Yongqi  SUN Jianqi  LI Fei  HE Shengping  Stein SANDVEN  YAN Qing  ZHANG Zhongshi  Katja LOHMANN  Noel KEENLYSIDE  Tore FUREVIK  SUO Lingling 《大气科学进展》2015,32(1):92-114

The Arctic plays a fundamental role in the climate system and has shown significant climate change in recent decades,including the Arctic warming and decline of Arctic sea-ice extent and thickness. In contrast to the Arctic warming and reduction of Arctic sea ice, Europe, East Asia and North America have experienced anomalously cold conditions, with record snowfall during recent years. In this paper, we review current understanding of the sea-ice impacts on the Eurasian climate.Paleo, observational and modelling studies are covered to summarize several major themes, including: the variability of Arctic sea ice and its controls; the likely causes and apparent impacts of the Arctic sea-ice decline during the satellite era,as well as past and projected future impacts and trends; the links and feedback mechanisms between the Arctic sea ice and the Arctic Oscillation/North Atlantic Oscillation, the recent Eurasian cooling, winter atmospheric circulation, summer precipitation in East Asia, spring snowfall over Eurasia, East Asian winter monsoon, and midlatitude extreme weather; and the remote climate response(e.g., atmospheric circulation, air temperature) to changes in Arctic sea ice. We conclude with a brief summary and suggestions for future research.  相似文献   

A critical appraisal of Sustainable Consumption and Production research: The reformist,revolutionary and reconfiguration positions     

《Global Environmental Change》2015

This conceptual review article provides a critical appraisal of Sustainable Consumption and Production research, which is currently framed by two generic positions. First, the ‘reformist’ position, which focuses on firms pursuing green eco-innovations and consumers buying eco-efficient products, represents the political and academic orthodoxy. Second, the ‘revolutionary’ position, which is a radical critique of the mainstream, advocates the abolishment of capitalism, materialism, and consumerism, and promotes values such as frugality, sufficiency, and localism. We find this dichotomous debate problematic, because it is intellectually stifling and politically conservative (in its outcomes). To move beyond this dichotomy, we propose a third position, ‘reconfiguration’, which focuses on transitions in socio-technical systems and daily life practices and accommodates new conceptual frameworks. For each of the three positions, we discuss: (1) the scale and type of change, (2) views on consumption and production in exemplary approaches, (3) underlying theoretical, epistemological and normative orientations, (4) policy implications, and (5) critical appraisal. The conclusion compares the three positions, provides arguments for the fruitfulness of the reconfiguration-position and offers four critical reflections about future Sustainable Consumption and Production research agendas.  相似文献   

农作物长势遥感监测业务化应用与研究进展   总被引：1，自引：0，他引：1  

陈怀亮  李颖  张红卫 《气象与环境科学》2015,38(1):95-102

农作物长势监测可为田间管理提供及时的决策支持信息和早期估产提供依据。为了更好地研究作物生长过程中不同遥感监测作物长势方法的适用性,从多光谱遥感数据、高光谱遥感数据和微波遥感数据的应用及遥感监测指标与模型模拟方面综述了国内外农作物长势遥感监测研究及业务化应用的最新进展,指出了未来拟重点加强的研究任务,包括高时空分辨率和高光谱分辨率遥感数据的业务化技术、多遥感反演参数协同监测作物长势技术研发、基于遥感信息与作物过程模型的集合预报技术研究、全球尺度作物长势监测业务运行系统研发。  相似文献