MODIS V006和V005全球反照率产品精度对比分析     

冯智明  闻建光  肖青  游冬琴  林兴稳  吴小丹 《遥感学报》2018,22(1):97-109

反照率作为一种非常重要的地表能量平衡、全球变化研究的参数,在众多研究领域中得到了广泛的应用,到目前为止已经有多种全球范围的反照率产品进行业务化生产和发布,针对不同反照率产品质量评价的研究也变得愈加重要。MODLAND团队在MODIS V005反照率产品反演算法的基础上通过改进16天周期内观测数据加权的方法生产出新版本的反照率产品MODIS V006。本文针对MODIS两个版本V005及V006的反照率产品,利用FLUXNET地面站点数据,比较验证两个版本反照率的总体精度以及在不同地表类型条件下的精度差异,同时通过交叉验证的方法分析二者的差异及稳定性。验证结果表明,MODIS V006反照率产品虽然在全反演高质量的数据比例上较V005有所下降,但是在同等条件下V006在提高时间分辨率的同时其精度也有所提高,在不同的地表类型条件下精度也优于V005,且在时间序列分布上具有稳定比例的高质量数据,可以满足大多数应用的精度需求。  相似文献   

地物波谱数据库建设进展及应用现状     

张莹彤  肖青  闻建光  游冬琴  窦宝成  唐勇  彭实 《遥感学报》2017,21(1):12-26

地物以其固有的特性反射、吸收、辐射和透射电磁波。不同地物表面对不同波长的电磁波反射/辐射/散射特性不同,成为利用遥感手段进行目标物探测与识别的理论基础,而地物波谱数据库的建成对定量遥感建模、地表参数反演及环境生态监测等具有重要作用。近年来,国内外各研究机构已建成部分地物波谱数据库,通过收集典型地物波谱数据,记录长期积累且相对稳定的波谱信息及其配套参数,支持地物分类、目标识别等领域的研究。本文综述了国内外主要地物波谱数据的建库历程,阐述了波谱数据库在各专业领域的主要应用成果,分析比较现有的国内外波谱数据库平台在波段覆盖、地物类型、配套参数及共享方式的特点及不足。在此基础上,针对波谱数据库在建设中存在的数据管理分散、测量质量控制和配套参数的标准规范不完善、数据利用效率不充分等问题,给出了初步建议。最后,探讨各学科对波谱数据库平台的应用需求,并对波谱数据库建设重点将面向全波段、多尺度、多时相的通用型知识库的发展趋势进行展望。  相似文献   

藏南地区历史地图地名表达研究     

刘东琴 《测绘科学》2019,44(6):291-295

针对目前我国公开出版的地图在藏南地区仅表示9个地名,远远不符合地图表达规则的问题,该文通过对藏南地区部分历史地图上地名的表达来探索藏南地名的合理表达。通过研究,该文获取了该区近100条历史地名,为地名合理表达提供了参考依据;同时,对这些地名的研究中,该文发现藏南地区地名烙上了中国印记,具有中国基因。  相似文献   

草原牧区旅游发展对牧户生计的影响 ——以内蒙古希拉穆仁草原为例   总被引：3，自引：1，他引：2  

李文龙  匡文慧 《地理科学》2019,39(1):131-139

草原牧区旅游发展是牧区实现乡村振兴的重要引擎。以内蒙古希拉穆仁草原旅游地牧户为研究案例,分析草原牧区旅游发展对牧户生计的影响。研究结果：① 草原旅游使牧户生计模式分化为纯牧户、务工主导型、旅游主导型、旅游专营型,且呈现纯牧户向务工主导型牧户过度,务工主导型牧户向旅游主导型牧户过度,旅游主导型牧户向旅游专营型牧户过度的一般演替规律;② 草原旅游发展总体上提高了牧户的生计资本存量,但不同类型牧户生计资本存量具有显著差异,生计资本存量由高到低排序为：旅游专营型牧户、旅游主导型牧户、务工主导型牧户、纯牧户;③ 牧户参与草原旅游,准则层因子障碍度由大到小排序为：人力资本、金融资本、物质资本、社会资本、自然资本;障碍度指数前6位的指标层因子分别是：成人受教育程度、成人劳动力人数、借债情况、社团网络、生产生活设备、社会参与;④ 不 同类型牧户参与草原旅游发展的首要障碍因素不同,纯牧户是受教育程度,务工主导型牧户是家庭人均收入,旅游主导型与旅游专营型牧户是借债情况。  相似文献   

香蒲、灯心草人工湿地的研究——Ⅰ.净化污水的效果   总被引：75，自引：5，他引：70  

成水平  况琪军  夏宜琤 《湖泊科学》1997,9(4):351-358

本文研究了种植香蒲Ｔｙｐｈａ ａｎｇｕｓｔｉｆｏｌｉａ或灯心草Ｊｕｎｃｕｓ ｅｆｆｕｓｕｓ的人工湿地对城镇污水和人工不污染物的净化效果,调查了香蒲,灯心草不同季节的生长差异及高浓度污水冲击负荷对其生长的影响。香蒲,灯心草人工湿地净化城镇污水,出水水质总体上达到国家Ⅱ,Ⅲ类地面水标准,灯心草湿地对人工污水中凯氏氮,总磷,化学耗氧量地去除率维持在９４％以上,氨氮的去除率为８２．７％－９９．７％;在正常  相似文献   

Continuous land cover change monitoring in the remote sensing big data era   总被引：3，自引：0，他引：3  

JinWei Dong  WenHui Kuang  JiYuan Liu 《中国科学:地球科学(英文版)》2017,60(12):2223-2224

<正>Since the late 20th century,global change issues have attracted lots of attention.As a key component of global changes,land cover and land use information has been increasingly important for improved understanding of global environmental changes and feedbacks between social and environmental systems(Verburg et al.,2015).A set of national and global scale land cover/use products with higher spatial and temporal resolutions have been developed to fill this gap.In China,existing efforts include China’s National  相似文献   

Importance Profiles for Water Vapor     

Brian Mapes  Arunchandra S. Chandra  Zhiming Kuang  Paquita Zuidema 《Surveys in Geophysics》2017,38(6):1355-1369

Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I ^m and TOA clear-sky outgoing longwave flux I ^OLR, in order to establish notation and illustrate graphically how the sensitivity profile or “kernel” depends on whether specific humidity S, relative humidity R, or ln(R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I ^con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I ^sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.  相似文献   

云县地震台DSQ水管倾斜仪与VP垂直摆观测资料对比分析     

曹白伦  何应文  匡福江  段勇 《地震地磁观测与研究》2017,38(3):128-133

云县地震台架设DSQ水管倾斜仪和VP垂直摆2套数字化地倾斜观测仪器,2套仪器的结构和原理差别较大,但观测的物理量一致。本文从数据完整率、内在精度、年变幅度、相关性、形态特征等角度出发,对数据进行对比分析,结果表明:2套仪器稳定性均较强,数据完整率较高,且地倾斜变化规律一致,均能反映监测区域大地倾斜变化特征,年变趋势受降雨干扰明显。  相似文献   

危机矿山深部及其外围盲矿预测的化探新方法及其最佳组合   总被引：10，自引：1，他引：9  

李惠 岑况沈镛立  吴悦斌张国义  张连发禹斌 《地质与勘探》2006,42(4):62-66

文章全面总结了国内外在找盲矿或隐伏矿方面的化探新方法、新技术研究成果,论述了各种方法的特点、用于盲矿或隐伏矿预测的有效性及其应用条件,在此基础上,提出了在危机矿山深部及其外围进行盲矿或隐伏矿定位预测的化探最佳方法及在不同条件下的最佳方法组合.  相似文献   

Reconstruction of nearshore chemical conditions in the Mesoproterozoic: evidence from red and grey beds of the Yangzhuang formation,North China Craton     

Yu Zou  Dongna Liu  Hongwei Kuang  Changgui Song  Yuxiang Sun 《International Geology Review》2020,62(11):1433-1449

ABSTRACT

Mesoproterozoic red beds near ancient coasts have not aroused extensive interest. A new geochemical study of the alternating red and grey dolostones from the Yangzhuang Formation provides a better understanding of the redox conditions of nearshore sedimentary environments. In this contribution, whole-rock samples are characterized by positive correlations of rare earth elements (REE) vs. Th and Fe_T vs. Th and flat-type REE distribution patterns, indicating massive terrigenous input, which is considered to be inherited from felsic rocks. Relatively high (Fe_mag+Fe_ox)/Fe_T and Fe³⁺/Fe²⁺ ratios in red beds indicate more oxidized conditions in supratidal environments compared with the lower oxygen contents in intertidal environments. Under these two distinct chemical sedimentary conditions, acetic acid-leached red and grey samples both have HREE-depleted distributions, suggesting significant freshwater invasion. Moreover, limited terrigenous redox-sensitive elements (RSEs) can reach the coast where the red beds are deposited, whereas relatively high RSE enrichment factors originating from shallow oceans are recorded in grey beds. In the Mesoproterozoic, limited oxidative weathering, shallow seawater desalination, and low organic production occurred near the coast. Meanwhile, a prolonged period of low Mo and U availability preserved in carbonate minerals confirmed that marine oxygen levels failed to satisfy the deposition of offshore red beds. During the regression, potentially exposed sediments connected to atmospheric oxygen guaranteed the oxidation of iron and the formation of red beds, and these events were coupled with negative δ¹³C_carb shifts in the Yanliao rift zone.  相似文献