柽柳灌丛沙堆及丘间地蚀积分布随背景植被变化的风洞实验

以塔克拉玛干沙漠南缘沙漠-绿洲过渡带广泛分布的柽柳灌丛沙堆及丘间地植物为原型,依据风沙运动相似理论,制作背景植被盖度依次为0%、4%、10%、16%和26%五组灌丛沙堆模型,在风洞中进行蚀积变化规律模拟实验。结果表明：柽柳灌丛沙堆及丘间地蚀积分布可划分为6个区域,依次为沙堆前积沙区、沙堆迎风坡风蚀区、沙堆两侧风蚀区、沙堆背风侧涡流积沙区、沙堆后尾流积沙区和不受沙堆影响区。随着指示风速增大,沙堆前积沙区和尾流积沙区范围缩小而沙堆两侧风蚀区面积明显增大。随着背景植被盖度的增大,沙堆前积沙区和尾流积沙区范围增大而沙堆两侧风蚀区范围明显减小。灌丛沙堆及丘间地整体风蚀面积比、风蚀率、各分区蚀积强度均呈指数规律递减。背景植被盖度为0%时,灌丛沙堆影响区风蚀率明显高于不受沙堆影响区,说明裸露地表条件下灌丛沙堆的存在会加剧地表风蚀;当背景植被盖度为4%~16%时,灌丛沙堆影响区风蚀率均低于不受沙堆影响区,可见丘间地植被存在可使灌丛沙堆起到一定的防风阻沙作用。当背景植被盖度>16%时,柽柳灌丛沙堆及丘间地整体蚀积强度和风蚀率变化趋于平稳。据此认为维持不低于16%的背景植被覆盖,是沙漠-绿洲过渡带柽柳灌丛沙堆科学保育的关键。     

CLOUD RADIATIVE AND MICROPHYSICAL EFFECTS ON THE RELATION BETWEEN SPATIAL MEAN RAIN RATE, RAIN INTENSITY AND FRACTIONAL RAINFALL COVERAGE

Cloud radiative and microphysical effects on the relation between spatial mean rain rate, rain intensity and fractional rainfall coverage are investigated in this study by conducting and analyzing a series of two-dimensional cloud resolving model sensitivity experiments of pre-summer torrential rainfall in June 2008. The analysis of time-mean data shows that the exclusion of radiative effects of liquid clouds reduces domain mean rain rate by decreasing convective rain rate mainly through the reduced convective-rainfall area associated with the strengthened hydrometeor gain in the presence of radiative effects of ice clouds, whereas it increases domain mean rain rate by enhancing convective rain rate mainly via the intensified convective rain intensity associated with the enhanced net condensation in the absence of radiative effects of ice clouds. The removal of radiative effects of ice clouds decreases domain mean rain rate by reducing stratiform rain rate through the suppressed stratiform rain intensity related to the suppressed net condensation in the presence of radiative effects of liquid clouds, whereas it increases domain mean rain rate by strengthening convective rain rate mainly via the enhanced convective rain intensity in response to the enhanced net condensation in the absence of radiative effects of liquid clouds. The elimination of microphysical effects of ice clouds suppresses domain mean rain rate by reducing stratiform rain rate through the reduced stratiform-rainfall area associated with severely reduced hydrometeor loss.     

科尔沁沙地东南缘近3000年来植被演化与人类活动

在科尔沁沙地东南部,以蒙古栎为代表的乔木花粉从３１００ａＢ．Ｐ．开始显著下降,蒿属和藜科等草本植物花粉逐渐上升,藜科花粉开始上升时间又迟于蒿属花粉。这说明,原业的固定沙丘有一部分首先转化为半固定沙丘,半固定沙丘后来又转变成半流动和流动沙丘。     

Scale Matching with Factorial Kriging for Improved Porosity Estimation from Seismic Data

When seismic data and porosity well logs contain information at different spatial scales, it is important to do a scale-matching of the datasets. Combining different data types with scale mismatch can lead to suboptimal results. A good correlation between seismic velocity and rock properties provides a basis for integrating seismic data in the estimation of petrophysical properties. Three-dimensional seismic data provides an unique exhaustive coverage of the interwell reservoir region not available from well data. However, because of the limitations of measurement frequency bandwidth and view angles, the seismic image can not capture the true seismic velocity at all spatial scales present in the earth. The small-scale spatial structure of heterogeneities may be absent in the measured seismic data. In order to take best advantage of the seismic data, factorial kriging is applied to separate the small and large-scale structures of both porosity and seismic data. Then the spatial structures in seismic data which are poorly correlated with porosity are filtered out prior to integrating seismic data into porosity estimation.     

Mapping Submerged Aquatic Vegetation with GIS in the Caloosahatchee Estuary: Evaluation of Different Interpolation Methods

This article evaluates different spatial interpolation methods for mapping submerged aquatic vegetation (SAV) in the Caloosahatchee Estuary, Florida. Data used for interpolation were collected by the Submersed Aquatic Vegetation Early Warning System (SAVEWS). The system consists of hydro-acoustic equipment, which operates from a slow-moving boat and records bottom depth, seagrass height, and seagrass density. This information is coupled with geographic location coordinates from a Global Positioning System (GPS) and stored together in digital files, representing SAV status at points along transect lines. Adequate spatial interpolation is needed to present the SAV information, including density, height, and water depth, as spatially continuous data for mapping and for comparison between seasons and years. Interpolation methods examined in this study include ordinary kriging with five different semivariance models combined with a variable number of neighboring points, the inverse distance weighted (IDW) method with different parameters, and the triangulated irregular network (TIN) method with linear and quintic options. Interpolation results were compared with survey data at selected calibration transects to examine the suitability of different interpolation methods. Suitability was quantified by the determination coefficient (R2) and the root-mean-square error (RMSE) between interpolated and observed values. The most suitable interpolation method was identified as the one yielding the highest R2 value and/or the lowest RMSE value. For different geographic conditions, seasons, and SAV parameters, different interpolation methods were recommended. This study identified that kriging was more suitable than the IDW or TIN method for spatial interpolation of all SAV parameters measured. It also suggested that transect data with irregular spatial distribution patterns such as SAV parameters are sensitive to interpolation methods. An inappropriate interpolation method such as TIN can lead to erroneous spatial representation of the SAV status. With a functional geographic system and adequate computing power, the evaluation and selection of interpolation methods can be automated and quantitative, leading to a more efficient and accurate decision.     

Effect of combining biogeotextile and vegetation cover on the protection of steep slope of highway in northern China: A runoff plot experiment

Biogeotextiles can be used to facilitate the formation of vegetation cover and to reduce soil erosion.Studies have demonstrated that only biogeotextile or vegetation cover can greatly reduce soil erosion.However, information about the effects of the combination of biogeotextile and vegetation cover on soil erosion is still limited, despite that the combination is the commonly practical form for bare road slope protection. Experimental plots, consisting of a relatively loose surface layer and a c...     

四川甲基卡锂矿伟晶岩转石分布区“3定2参”大比例尺填图法及其在青藏高原应用的意义

我国西部地区无论是新疆阿尔泰还是地处青藏高原的西昆仑地区或是松潘-甘孜成矿带,都是我国伟晶岩型矿床找矿远景区,但要么剥蚀严重,要么第四系覆盖,难以找到好的地质露头。本文以地处青藏高原东南缘的川西甲基卡矿田为例,通过近10年来的实践,探索出一套在第四系覆盖严重但又有伟晶岩转石分布地区的填图找矿方法--"3定2参"1∶2000伟晶岩转石填图法,即:定伟晶岩转石类型、尺度、密度,参考矿区内伟晶岩脉产状和地形条件。实践证明,该方法能够快速有效识别伟晶岩转石类型(冰碛物、坡积物和原地或半原地型),并可进一步确定第四系覆盖区内伟晶岩脉的类型、产状及规模,为钻探工程部署提供依据。2019年在甲基卡经8个钻孔验证,在日西柯第四系覆盖区内发现16条花岗伟晶岩脉,其中锂辉石伟晶岩脉10条,实现了新的找矿突破。这一方法同样在可尔因矿集区适用,并指导2019年"松潘-甘孜成锂带锂铍多金属大型资源基地综合调查评价"项目在上述两个地区实施钻探验证,初步探获新增氧化锂资源量超过15万吨,值得进一步推广应用。     

导航星座抗毁路由方法与技术研究

基于分群管理、群首备份、链路冗余、链路修补的二代导航卫星网络组网结构,提出并设计了一种基于GEO星层、MEO星层、地面节点联合组网的抗毁路由算法（DRRA）。基于二代导航动态卫星网络中卫星移动的动态卫星网络中,提出的DRRA算法在定位信号稳定、数据包路由抗毁、数据包路由最短延时等方面具有优势,并分析了其主要原因。     

导航星座抗毁组网结构研究

为提高整个二代导航卫星网络的抗毁性能,对其抗毁组网结构进行了研究。基于分群管理、链路冗余与修补方法,提出并设计分析了一种基于GEO星层、MEO星层以及地面节点联合组网的二代导航卫星网络组网结构,根据快照周期内位置固定的方法对星座中MEO星层进行分群管理,设计其群首的备份选择机制,以及群首MEO替代失效群管理者GEO机制,提高了星座网络的通信链路的抗毁性。通过分析二代导航卫星网络中数据传输过程与类型,设计网络结构中群内、星层以及整个二代导航星座的通信链路,特别是对星座中MEO星层的通信链路进行充分的冗余设计,启用视距范围内间隔失效卫星间次相邻卫星节点链路连接的链路设计,并同时提高了整个二代导航卫星网络的通信性能和通信容量,可以满足各种不同业务需求的数据包传输。     

国家1:50000数据库更新工程总体设计研究与技术创新

为了全面提高1:50000数据库的信息现势性和要素完整性,我国"十一五"期间组织实施了国家1:50000数据库更新工程.介绍该工程总体技术研究与技术创新工作,包括研究设计以地形数据全要素更新、全区域变化检测和全过程质量控制为主要特征的1:50000数据库全面更新模式,研究提出符合我国大面积快速更新实际需要的缩编更新优先、影像一体化更新为主的主体更新方法,设计研制规模化更新所需的生产技术系统,制定配套的生产技术规定,建立规模化更新生产业务体系,并在全国大规模更新生产中广泛使用.

Abstract：

The currency of geographic data refers to its consistency with respect to the real world, and plays a criti-cal role in geographic information service and applications. In order to improve the quality of geographic informa-tion service, State Bureau of Surveying and Mapping of China had launched a five year's national campaign to up-date 1 : 50000 topographic database. This paper outlines the master design and technical development of this na-tional updating engineering, which adopts a full coverage updating strategy characterized by all element topo-graphic data modeling, change detection in all related areas, and whole process data quality controlling. High resolution image-based updating and large-scale data generalization-based updating were developed and used as two majors updating techniques, a series of technical production specifications were made, Based on the above, a technical system for large scale updating production, mainly including image based updating software and data generalization based updating software, has been developed and equipped to a large number of production units. The new technical pro-duction system has been successfully implemented in national campaign to update 1 : 50000 topographic database.