植物营养胁迫与光谱特性   总被引：33，自引：2，他引：31  

王珂  沈掌泉  王人潮 《国土资源遥感》1999,10(1):9-14

主要介绍了植物营养胁迫与光谱特性的关系,列举了多个用植物光谱分析方法诊断植物营养水平的实例,提出了提高诊断精度的几种途径。  相似文献   

TOVS资料的变分处理方法在青藏高原地区的数值试验   总被引：16，自引：2，他引：14  

翁永辉  徐祥德 《大气科学》1999,23(6):703-712

首次在测站稀少的高原地区引入经变分技术处理的TOVS资料,使用MM5数值模式对高原地区降水数值预报难点进行了研究。探讨了解决高原地区测站少、数值预报模式初始场信息误差大的技术关键问题,提出了采用TOVS资料在高原地区增加初始场信息的构思。数值试验结果表明,应用变分法处理后的TOVS资料,可显著地提高高原初始场信息的可靠性。考虑夏季高原地区是对流多发区特点,本文采用非静力MM5模式,并在模式初始场中增加了TOVS资料,弥补了测站稀少的高原地区使用非静力模式的不足之处。研究结果表明,本文采用的TOVS资料技术方案可能是高原区域数值模式降水预报的有效途径,并为开拓卫星资料的应用领域提供了技术思路与理论分析依据。  相似文献   

风成沉积石英绿光释光测年的单片技术   总被引：6，自引：1，他引：5  

赖忠平  周杰  卢演俦  A.K.Singhvi 《中国沙漠》1999,19(4):403-406

运用再生法进行单片技术测年所面临的主要问题是感量变化。论文探讨了石英绿光释光测年中对感量变化进行校正的方法,然后运用单片技术对沙漠黄土边界带风成沉积沙样进行等效剂量测定。结果表明,单片技术是石英绿光释光测年的理想手段。  相似文献   

Extrapolation of symplectic Integrators     

S. Blanes  F. Casas  J. Ros 《Celestial Mechanics and Dynamical Astronomy》1999,75(2):149-161

We build high order numerical methods for solving differential equations by applying extrapolation techniques to a Symplectic Integrator of order 2n. We show that, in general, the qualitative properties are preserved at least up to order 4n+1. This new procedure produces much more efficient methods than those obtained using the Yoshida composition technique. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

小型水库集约化养鱼技术研究     

赵振伦  杨沁芳 《湖泊科学》1993,5(3):244-252

江苏省瓦沟水库和石山头水库,面积为8.9和17.3hm~2,1984年起分别进行集约化养鱼试验。内容是改革我国传统的水库养鱼方式,设计多种混放密养的养殖模式,增加外源性饵料,改善水库饵料基础,加大鱼种放养规格,缩短饲养周期,实行库湾、池塘等多种培育鱼种形式,实现鱼种自给,开展网箱养鱼,设置网箱簖进行轮捕,饲养家禽家畜,种植青绿饲料,注重综合养鱼。试验结果每公顷鱼产量,瓦沟水库由试验前(1983年)每公顷195kg至1986年达4176kg;石山头水库由1984年的86kg至1989年增加至7822kg,公顷渔业利润为10140元。现这项技术已在江苏省51座小型水库中推广应用。  相似文献   

Optimum observing strategies     

L. Kahl Kristensen 《Astronomische Nachrichten》2001,322(1):47-56

The distribution of observations giving the smallest errors for specific purposes is found in the general case by a numerical procedure. Examples consider the minimum error ellipse for the recovery of a distant asteroid, a main belt object and the position in the target plane for a close approach to the Earth. The observations should be performed only on a few critical nights and inefficient times avoided. The methods are of interest for the optimum strategies for surveys and the determination of initial orbits.  相似文献   

卫星图像实时接收及回显技术研发          下载免费PDF全文

张玺 《气象》2007,33(12):98-102

为了快捷而方便地实时接收卫星图像并进行质量分析,在运行控制系统的图像子系统中开发了卫星图像实时接收及回显主控接口软件。该软件是在SGI工作站上以UNIX操作系统为平台,运用X窗口系统、MOTIF窗口管理器和SGI公司的IRISGL的图形技术,采用C语言编写的。通过控制界面和控制选项实时接收卫星图像并将从磁盘或磁带上传输过来的图像资料进行各种回放显示、加网格、黑体定标、图像定位、提取周时间表等显示处理并进行质量分析。该软件已运用在气象卫星资料的实时处理中。  相似文献   

天然地震识别与震相自动拾取技术进展     

孙印  潘素珍  刘明军 《中国地震》2018,34(4):606-620

震相拾取是地震数据处理过程中最基本的步骤之一。在传统的人工拾取技术不能满足庞大的地震数据处理需求的情况下,震相自动拾取技术从产生到发展至今经历了漫长的过程。本文回顾并总结了震相自动拾取技术的发展状况,重点介绍了长短时窗法、赤池准则法、模板匹配技术、基于自相关盲搜索的FAST法、S波偏振分析法、人工智能方法等,以及近年发展起来的多频率震相识别、全波形叠加、二次方自回归模型等方法,同时分析了每种方法的优势和局限性。  相似文献   

Gully morphological characteristics in the loess hilly‐gully region based on 3D laser scanning technique          下载免费PDF全文

Hongyan Wu  Ximeng Xu  Fenli Zheng  Chao Qin  Xu He 《地球表面变化过程与地形》2018,43(8):1701-1710

Gully morphology characteristics can be used effectively to describe the status of gully development. The Chabagou watershed, located in the hilly‐gully region of the Loess Plateau in China, was selected to investigate gully morphological characteristics using a 3D laser scanning technique (LIDAR). Thirty‐one representative gullies located at different watershed locations and gully orders were chosen to quantitatively describe gully morphology and establish empirical equations for estimating gully volume based on gully length and gully surface area. Images and point cloud data for the 31 gullies were collected, and digital elevation models (DEMs) with 10‐cm resolution were generated. ArcGIS 10.1 was then used to extract fundamental gully morphological parameters covering gully length (L), gully width (W_T) and gully depth (D), and some derivative morphological parameters, including gully head curvature (C), gully width–depth ratio (w/d), gully bottom‐to‐top width ratio (W_B/W_T), gully surface area (A_g) and gully volume (V_g). The results indicated that gullies in the upper watershed and the second order were more developed based on their high values of gully head curvature. The potential for gully development increased from the second order to the fourth order. Within the same gully orders, gullies in the lower watershed were more active with more development potential. A method for differentiating between gully head and gully sidewalls based on the gully head curvature value was proposed with a mean relative error of 8.77%. U‐shaped cross‐sections were widely distributed in the upper watershed and upper positions of a gully, while V‐shaped cross‐sections were widely distributed in the lower watershed and lower positions of a gully. V–L and V–A_g empirical equations with acceptable accuracy were established and can be used to estimate gully erosion in the Loess hilly‐gully region. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Spatial modeling of pyroclastic cover deposit thickness (depth to bedrock) in peri‐volcanic areas of Campania (southern Italy)          下载免费PDF全文

Matteo Del Soldato  Veronica Pazzi  Samuele Segoni  Pantaleone De Vita  Veronica Tofani  Sandro Moretti 《地球表面变化过程与地形》2018,43(9):1757-1767

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