一种近区地表地物重力改正的方法

利用重力等值原理,求物体质心的方法,针对高精度重力测量中常见的地表地形、地物的重力异常影响,提出了一种近区地表地物的改正方法。     

偏重钻铤在丁集矿冻结造孔施工中的应用

钻井技术的关键是预防及控制孔斜,通过对目前常用4种防斜钻具组合的适岩性、井深、井斜及钻效等指标对比,在冻结造孔施工中选用了适用地层广、防斜性能好并具有纠斜作用的偏重钻铤。为发挥偏重钻铤的防斜作用,宜增大转速,并使钻铤减去部分的重量应位于离轴线尽可能远的部位。在淮南丁集冻结孔施工的三十多口钻孔中,井斜一般均在0．5°以内,钻效超过2400m/台·月。     

导航卫星的单星定轨

本文对导航卫星的单星定轨进行了初步探讨，针对单星定轨时卫星钟钟差和接收机钟钟差难以处理的特点，提出了定轨的同时解算测站距离偏差和采用平均距离变化率进行定轨两种方案，采用GPS的实测数据试验计算表明，两种计算方案均能初步完成单星定轨任务。     

流域地形自动分割研究

本文提供了基于栅格数字高程模型（ＤＥＭ）提取流域空间结构,进行流域自动分割的技术方法。该方法包括地貌形态结构定义、流域结构定义和算法设计３个部分。基于本文设计的算法,可以从ＤＥＭ提取完整的汇流网络和分水线网络,两者组成的多边形集把流域分割成具有拓扑结构的多个子汇流区,这个子汇流区集作为存贮流域信息的基本地貌单元,是流域信息进入地学数据库的框架,也是进行空间分布式机理──过程流域分析模型的基础。并以山西离石黄土丘陵沟壑区的王家沟流域为试验区,获得了较为满意的结果。     

Pliocene aridity and Neogene landscape evolution recorded by a fluvial sediment system (Campaspe Formation) in northeast Queensland

Campaspe Formation, a surficial, fluviatile, sand-dominated unit, is extensively developed in the Charters Towers region of north Queensland where it covers an area of 11 000 km², overlying Paleozoic basement and erosional remnants of Paleogene Southern Cross Formation. In the northern part of its distribution, it is interlayered with, and overlain by, flows of Nulla Basalt. It is dated as mid-Pliocene, based on the 3.48 Ma age of the Myrrilumbing Flow interlayered with its upper part, an antiquity consistent with thin ferricrete locally developed at its surface. The formation defines the Campaspe Surface at an elevation of 200–440 m in the present landscape, falling gently from upland to the west towards the current channel of the Burdekin River. This surface is a relict alluvial plain little incised by easterly flowing tributaries of the Burdekin River and has survived, essentially intact, from the early Pliocene. Geometry of the formation is established from some 2000 mineral exploration drill holes and seismic profiling. It has an average thickness of some 60 m, reaching a maximum of over 200 m. It blankets a pre-existing, low relief landscape in which a basement ridge divides it into two sub-basins that mirror the present drainage. The formation consists of poorly sorted sandstone with minor conglomerate and siltstone, and contains paleosol horizons with associated calcrete. Matrix supported sandstone in the succession, indicates deposition in part from hyperconcentrated flows. Sandstones generally show poorly defined planar layering as typical of ephemeral overbank and terminal splay sediment bodies but beds with cross-lamination, indicating fluvial channel bed forms, are also present. They are characterised by pore-filling silt and mud, largely emplaced by post-depositional infiltration, such that the unit produces essentially no groundwater. Facies attributes are consistent with fluvial deposition in ephemeral, dry climate, distributary system, with inefficient cross-drainage discharge that induced aggradation, resulting in a substantial sediment body perched in the landscape. Framework grain compositions show the formation to be mineralogically mature, representing erosional debris derived from intense weathering in an earlier climatic regime recorded, at least in part, by duricrust developed in the fluviatile–lacustrine Southern Cross Formation of Paleogene age. Such duricrust intervals are now upstanding in the landscape, representing erosional remnants from inverted relief developed in a mid-Cenozoic, pluvial, landscape cycle. Paleoclimatic signature of the Campaspe Formation extends the record of Pliocene aridity, widely recognised elsewhere in Australia, to northeast Queensland. In large part the landscape of the Charters Towers district is relict from the early Pliocene and is in the process of readjusting to more pluvial climatic regimes. By implication, Pliocene aridity has, on a small scale, exerted a strong influence on the present physiography of Australian landscapes.     

Importance of no‐rain measurements on the comparison of radar and rain gauge rain rate

This study evaluated four possible cases of comparing radar and rain gauge rain rate for the detection of mean‐field bias. These four cases, or detection designs, consider in this study are: (1) design 1‐uses all the data sets available, including zero radar rain rate and zero rain gauge rain rate, (2) design 2—uses the data sets of positive radar rain rate and zero or positive rain gauge rain rate, (3) design 3—uses the data sets of zero or positive radar rain rate and positive rain gauge rain rate and (4) design 4—uses the data sets of positive radar rain rate and positive rain gauge rain rate. A theoretical review of these four detection designs showed that only the design 1 causes no design bias, but designs 2, 3 and 4 can cause positive, negative and negative design biases, respectively. This theoretical result was also verified by applying these four designs to the rain rate field generated by a multi‐dimensional rain rate model, as well as to that of the Mt Gwanak radar in Korea. The results from both applications showed that especially the design 4, which is generally used for the detection of mean‐field bias of radar rain rate, causes a serious design bias; therefore, is inappropriate as a design for detecting the mean‐field bias of radar rain rate. Copyright © 2009 John Wiley & Sons, Ltd.     

疫情防控期“数字地形测量学”线上教学实践

疫情之下,在线教学为“停课不停教、停课不停学”提供了理想的教学方案。基于超星泛雅网络教学平台,以“数字地形测量学”在线课程建设为例,探索在线课程的建设方法与途径,构建“能学、辅教”的立体化教学资源,进行“超星泛雅+学习通+腾讯课堂+课程QQ群”混合教学模式的探索和实践,为在线课程建设与应用提供借鉴。     

基于FME的CASS格式地形图入库方案及程序设计

结合秦皇岛市2018年基础图入库工作,针对原始数据的特点,基于FME设计了入库方案,编写了转换模版,使大部分数据处理、检查等工作由计算机自动完成。其转换成果精度好,属性完整,错误率低,有效的减轻了人工作业负担,提高了生产效率。     

利用众源地理数据快速测制大比例尺军事地形图

针对特战实训演练中大比例尺军事地形图数据不足、现势性较差的问题,从特战用图需求出发,基于众源地理数据提出了一种快速、高效、经济、准确的大比例尺军事地形图测制方法。首先,介绍了众源地理数据的概念和特点,研究了众源地理数据的来源和获取方法。然后,在顾及军事地形图与民用地形图之间制图表达的差异后,设计了利用众源地理数据绘制大比例尺军事地形图的工艺流程。最后,基于ArcMap,绘制了某地1∶1万军事地形图并进行实验验证和精度分析。实验结果表明,该方法既可有效提高作业效率,又能满足成图精度要求,可为军事教学训练、指挥员用图决策提供重要参考。     

Seasonal prediction of June rainfall over South China: Model assessment and statistical downscaling

The performances of various dynamical models from the Asia-Pacific Economic Cooperation(APEC) Climate Center(APCC) multi-model ensemble(MME) in predicting station-scale rainfall in South China(SC) in June were evaluated.It was found that the MME mean of model hindcasts can skillfully predict the June rainfall anomaly averaged over the SC domain.This could be related to the MME's ability in capturing the observed linkages between SC rainfall and atmospheric large-scale circulation anomalies in the Indo-Pacific region.Further assessment of station-scale June rainfall prediction based on direct model output(DMO) over 97 stations in SC revealed that the MME mean outperforms each individual model.However,poor prediction abilities in some in-land and southeastern SC stations are apparent in the MME mean and in a number of models.In order to improve the performance at those stations with poor DMO prediction skill,a station-based statistical downscaling scheme was constructed and applied to the individual and MME mean hindcast runs.For several models,this scheme can outperform DMO at more than 30 stations,because it can tap into the abilities of the models in capturing the anomalous Indo-Paciric circulation to which SC rainfall is considerably sensitive.Therefore,enhanced rainfall prediction abilities in these models should make them more useful for disaster preparedness and mitigation purposes.