Assessment of Wet Season Precipitation in the Central United States by the Regional Climate Simulation of the WRFG Member in NARCCAP and Its Relationship with Large-Scale Circulation Biases

Assessment of past-climate simulations of regional climate models(RCMs)is important for understanding the reliability of RCMs when used to project future regional climate.Here,we assess the performance and discuss possible causes of biases in a WRF-based RCM with a grid spacing of 50 km,named WRFG,from the North American Regional Climate Change Assessment Program(NARCCAP)in simulating wet season precipitation over the Central United States for a period when observational data are available.The RCM reproduces key features of the precipitation distribution characteristics during late spring to early summer,although it tends to underestimate the magnitude of precipitation.This dry bias is partially due to the model’s lack of skill in simulating nocturnal precipitation related to the lack of eastward propagating convective systems in the simulation.Inaccuracy in reproducing large-scale circulation and environmental conditions is another contributing factor.The too weak simulated pressure gradient between the Rocky Mountains and the Gulf of Mexico results in weaker southerly winds in between,leading to a reduction of warm moist air transport from the Gulf to the Central Great Plains.The simulated low-level horizontal convergence fields are less favorable for upward motion than in the NARR and hence,for the development of moist convection as well.Therefore,a careful examination of an RCM’s deficiencies and the identification of the source of errors are important when using the RCM to project precipitation changes in future climate scenarios.

Large-scale spatial data visualization method based on augmented reality

Background A task assigned to space exploration satellites involves detecting the physical environment within a certain space.However,space detection data are complex and abstract.These data are not conducive for researchers'visual perceptions of the evolution and interaction of events in the space environment.Methods A time-series dynamic data sampling method for large-scale space was proposed for sample detection data in space and time,and the corresponding relationships between data location features and other attribute features were established.A tone-mapping method based on statistical histogram equalization was proposed and applied to the final attribute feature data.The visualization process is optimized for rendering by merging materials,reducing the number of patches,and performing other operations.Results The results of sampling,feature extraction,and uniform visualization of the detection data of complex types,long duration spans,and uneven spatial distributions were obtained.The real-time visualization of large-scale spatial structures using augmented reality devices,particularly low-performance devices,was also investigated.Conclusions The proposed visualization system can reconstruct the three-dimensional structure of a large-scale space,express the structure and changes in the spatial environment using augmented reality,and assist in intuitively discovering spatial environmental events and evolutionary rules.

The Gestalt Function of Landscape Building in Terrain Environment

The outstanding value of landscape building is mainly reflected in the isomorphic relationship with the environment.If properly placed,it can play a key role in the natural landscape,which puts forward higher requirements for the site selection,modeling,volume and material selection of buildings.As a prerequisite,site selection is more demanding.Based on the previous studies of geomancy,the author summed up four types of site selection:gathering potential,blocking pass,bundle vein and acupoint from the isomorphic relationship between the landscape building and terrain in Wuling Area,analyzed its gestalt function and ecological ethics from the perspective of Gestalt psychology and ecological perception theory,explored the fit between the traditional Fengshui regulations and the Gestalt theory,and further revealed the influence of the accumulated genetic function of local living experience and survival wisdom on people’s deep psychological structure.

Computational fluid dynamics evaluation of the effect of different city designs on the wind environment of a downwind natural heritage site

Disturbance in wind regime and sand erosion deposition balance may lead to burial and eventual vanishing of a site.This study conducted 3D computational fluid dynamics(CFD)simulations to evaluate the effect of a proposed city design on the wind environment of the Crescent Spring,a downwind natural heritage site located in Dunhuang,Northwestern China.Satellite terrain data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)Digital Elevation Model(DEM)were used to construct the solid surface model.Steady-state Reynolds Averaged Navier-Stokes equations(RANS)with shear stress transport(SST)k-ωturbulence model were then applied to solve the flow field problems.Land-use changes were modeled implicitly by dividing the underlying surface into different areas and by applying corresponding aerodynamic roughness lengths.Simulations were performed by using cases with different city areas and building heights.Results show that the selected model could capture the surface roughness changes and could adjust wind profile over a large area.Wind profiles varied over the greenfield to the north and over the Gobi land to the east of the spring.Therefore,different wind speed reduction effects were observed from various city construction scenarios.The current city design would lead to about 2 m/s of wind speed reduction at the downwind city edge and about 1 m/s of wind speed reduction at the north of the spring at 35-m height.Reducing the city height in the north greenfield area could efficiently eliminate the negative effects of wind spee.By contrast,restricting the city area worked better in the eastern Gobi area compared with other parts of the study area.Wind speed reduction in areas near the spring could be limited to 0.1 m/s by combining these two abatement strategies.The CFD method could be applied to simulate the wind environment affected by other land-use changes over a large terrain.

Integrated controlling technique of ecological environment in Shendong Mining Area

To enclose the interactive relation between the underground mining with suitable protection for surface ecological environments and surface prevention of ecological environments adapting to mining disturbing was researched and developed core of this technique. There are three aspects of controlling ecological environments, to dispose and renew before exploitation, to protect surface ecological environments in the exploitative process and to repair and build up after exploitation. Based on the moving law of overburden strata in shallow seam, the surface subsidence law and the growth law of vegetation in subsidence mine area, the integrated controlling technique has been developed synthetically by methods of theoretic analysis, laboratory simulation, numerical calculation, commercial test etc.. It includes the key techniques of aquifer-protective mining, filtering and purging of mine water through goaf, preventing and extinguishing fire in shallow seam no-rock roadway layout and waste disposal in underground, frame-building ecological functional sphere before exploitation, frame-building the ecological cycle using system after mining and so on.

Study on the Marine Sedimentary Environment Evolution of the Southern Laizhou Bay Under the Impact of Port Projects

The southern Laizhou Bay is mainly composed of silt-sandy coasts with diverse landforms, and its marine hydrodynamic environment is sensitive to human activities. Marine hydrodynamic and sedimentary environments of the study area have changed under the influence of large-scale port projects in recent years. In this paper, the evolution of hydrodynamic environment, deposition rate, and geochemical characteristics were studied based on sediment grain size, element analysis and ^(210)Pb dating of two cores, in order to analyze the influence of Weifang Port on marine environmental evolution, and provide theoretical and practical basis for protecting marine environment in developing marine resources reasonably. Results showed that sediments of the two cores were relatively coarser and mainly composed of silty sand. Sediments above 230 cm in core WF1 and 218 cm in core WF2 were deposited since 1855 when the Yellow River appeared to deposit its sediments within the modern active delta, and the average deposition rate was between 0.3 and 0.5 cm a^(-1). Implement of Weifang Port projects in 1997 and 2007 created great influence on the sedimentary environment evolution in the surrounding waters, and the deposition rate was significantly increased. The average annual deposition rates were 5.1 cm and 3.5 cm in WF1 and WF2 respectively between 1997 and 2007. Content of heavy metals in sediments showed no obvious change in the vertical, indicating that the heavy metals were less affected by human activity and there was no significant accumulation of such metals in the study area.

Evaluation of Mine Geological Environment of Guqiao Coalmine

The geological environment is important for the development of coal enterprises. In the Guqiao coalmine, the information of coal mining subsidence, terrain landform, coal gangue utilization, mine water treatment and several on-site investigations have been analyzed. It holds that its geological environment can be evaluated from three aspects, i.e., geological disasters, terrain and landform destruction, and influence on water and soil environment. The results show that mining activities have serious impacts on geological disasters and terrain landform, while lighter impacts on the water and soil environment. According to the research results, a set of corresponding governance strategies are given. The findings can provide theoretical support for the geological environmental protection and restoration of the Guqiao coalmine.

Effect of terrain on landscape patterns and ecological effects by a gradient-based RS and GIS analysis

Terrain is an important environment factor that plays a vital role in human development by influencing the spatial layout of land use patterns. The terrain niche index, combined with slope and elevation, can comprehensively present detailed information about spatial differences in terrain and is superior to single terrain factors. We applied remote sensing and geographical information system to terrain gradient, used the non-dimensional distribution index to examine spatial distribution characteristics of various landscape types, and analyzed the ecological effects of landscape were quantitatively on terrain gradients. Eco-environment quality (EEQ) was evaluated using the forestry operation area as the evaluation unit. The spatial distributions in various landscapes were significantly influenced by terrain factors, especially by bodies of water, cropland and residential land. The spatial distribution varied greatly in different terrain gradients for similar landscape types. The areas associated with good, intermediate and poor EEQ were occupied primarily by natural landscape, semi-natural and largely artificial landscapes, respectively.

Automatic Terrain Debris Recognition Network Based on 3D Remote Sensing Data

Although predecessors have made great contributions to the semantic segmentation of 3D indoor scenes,there still exist some challenges in the debris recognition of terrain data.Compared with hundreds of thousands of indoor point clouds,the amount of terrain point cloud is up to millions.Apart from that,terrain point cloud data obtained from remote sensing is measured in meters,but the indoor scene is measured in centimeters.In this case,the terrain debris obtained from remote sensing mapping only have dozens of points,which means that sufficient training information cannot be obtained only through the convolution of points.In this paper,we build multi-attribute descriptors containing geometric information and color information to better describe the information in low-precision terrain debris.Therefore,our process is aimed at the multi-attribute descriptors of each point rather than the point.On this basis,an unsupervised classification algorithm is proposed to divide the point cloud into several terrain areas,and regard each area as a graph vertex named super point to form the graph structure,thus effectively reducing the number of the terrain point cloud from millions to hundreds.Then we proposed a graph convolution network by employing PointNet for graph embedding and recurrent gated graph convolutional network for classification.Our experiments show that the terrain point cloud can reduce the amount of data from millions to hundreds through the super point graph based on multi-attribute descriptor and our accuracy reached 91.74%and the IoU reached 94.08%,both of which were significantly better than the current methods such as SEGCloud(Acc:88.63%,IoU:89.29%)and PointCNN(Acc:86.35,IoU:87.26).

电大山区地物环境中电波传播的电磁计算

在无人驾驶与无人机等新兴行业中,信号覆盖范围的要求较高,不仅仅在城市,在人迹罕至的山地、沙漠、森林中也需要无线信号的覆盖才能真正完成远程操控,这些地区更多需要考虑的是地势变化对电磁传播所带来的影响。计算电磁学中的一致性几何绕射理论方法是分析电大环境电磁问题的有效方法,使用计算电磁学的方法研究电磁波在山区地物环境中的传播规律。给出了一种建立不规则地形模型的新方法,可以通过数字高程的网格数据生成电磁算法可用的三次多项式曲面,使用多个立方曲面对不规则地形进行拼接,使用平均均方根误差验证模型数据的准确性。基于所得的地形数据,完成了并行的几何光学算法,并对区域电磁场的分布进行了仿真计算。选取了实际山区地物环境进行了实地测量,测量结果与仿真结果对比趋势一致,验证了该方法在非规则地形中电磁波传播分析中的有效性。考虑环境电磁计算的规模,建立了相应的并行策略,100核测试的并行效率可以保持在80%以上。

川西南山区县域数字土壤制图研究

【目的】研究环境变量的筛选和土壤类型空间推理方法的选择,为有效提高县域数字土壤制图精度提供参考。【方法】以四川省盐源县为研究区,将气候要素、地形数据和遥感影像作为推理制图的辅助因子,利用野外采样点数据和环境协变量因子,采用决策树分类方法对环境特征进行重要性排序,特征筛选和组合优选,通过对比决策树分类、支持向量机和随机森林3种土壤分类方法的制图精度,探索基于土壤-环境关系理论提高具有立体气候特征的山区县域数字土壤制图精度的途径。【结果】(1)气候和地形特征在研究区土壤分类中起重要作用,采用单一气候因素作为土壤筛选分类的环境变量可获得土壤分类筛选精度为83.22%,依次增加地形和生物特征可分别使筛选精度提升至85.78%和89.43%;(2)与其他模型相比,随机森林模型制图效果更好,对比采样点数据的土壤分类总体精度为77.10%,Kappa系数为0.72;(3)气候因子以及地形因素对水热条件的影响是决定研究区土壤类型空间分布异质性的主要原因,年均气温、年积温、年降水量、相对湿度、高程、地形湿润度等环境特征因子与研究区主要土壤类型的空间分布关系密切。【结论】在具有立体气候特征的山区,基于随机森林方法使用气候、地形和遥感数据进行数字土壤分类制图有较好的效果。

滆湖北部人工地形重塑下风浪场变化研究

风浪是影响浅水湖泊物理生境环境重要的水动力要素之一。基于滆湖实测风浪数据,建立了滆湖风浪模型,验证结果表明模型可以较好模拟滆湖风浪随风场变化情况。在此基础上开展滆湖北部水域在人工地形重塑工程实施后的风浪变化情况分析。结果表明,不同季节盛行风下,风浪强度和湖底扰动强度均有一定程度的衰减,这有利于水体透明度和水底光照条件的改善。风浪强度的衰减使得具有有利于水生植物生长与发育风浪条件的水域面积显著扩增。人工地形重塑的实施,有利于滆湖北部水域水生植被物理生境环境改善,从而为滆湖北部水域水生植被的修复提供较好的环境支撑,也为其他浅水湖泊地形重塑工程的实施提供借鉴。

非结构地形环境下基于特征融合的倾斜摄影测绘建模优化方法

[目的]利用无人机进行大尺度非结构地形环境测绘时,由于无人机倾斜摄影得到的图像在测绘建模时会存在仿射变形较大、透视畸变严重、局部特征变化各异等问题,进而导致建模数据匹配困难.为解决这一问题,本文提出了一种基于特征融合的倾斜摄影测绘建模优化方法.[方法]首先融合图像的颜色信息及近似最近邻快速库(fast library for approximate nearest neighbors, FLANN)优化的加速稳健特征(speed up robust feature, SURF),然后结合优化的SURF与最稳定颜色区域特征(maximally stable color regions, MSCR)实现仿射变形图像间快速准确的特征提取及匹配.[结果]本文的特征匹配算法在1.25 s内得到757个最佳匹配点;相对于基于尺度不变特征(scale-invariant feature transform, SIFT)、SIFT+MSCR和SURF的特征匹配算法,最佳匹配点的数量分别提高141%、29%和34%,匹配时间与SURF接近,远低于SIFT和SIFT+MSCR.测绘建模得到的点云与参考点在三个方向上的距离均方根误差在7 cm以内,平均误差在11 cm以内.[结论]本文提出的算法能够实现非结构地形环境的全局三维模型快速准确构建,同时数据匹配过程中具有更良好的匹配效果和匹配效率.

山地城市居民低碳出行意愿组态路径研究——以贵阳市为例

为切实缓解城市拥堵,营造绿色生态环境,居民低碳出行已成为学界研究热点。基于贵阳市居民低碳出行意愿调查数据,借鉴计划行为理论,考虑主观建成环境感知、环境意识因素,同时,引入地形感知变量(坡度感知、出行过程感知、绕行距离感知),运用模糊集定性比较方法(fsQCA),探讨因素间组态构型对居民低碳出行意愿的影响。结果表明:环境意识可单独构成居民低碳出行意愿的必要条件;通过分析得出6条高低碳出行意愿路径组合,即知觉控制主导型、环境意识主导型、建成环境主导型、均衡性、缺失过程感知主导型、坡度感知主导型;其中,主观建成环境感知、知觉行为控制成为触发居民低碳出行意愿的重要核心条件,在坡度感知方面,低绕行距离感知、低出行过程感知,可激发居民低碳出行意愿,而坡度感知的影响存在差异。结论有助于拓展低碳出行意愿研究视角,为政府有效提高山地城市居民低碳出行意愿提供了实践启示。

基于遥感生态指数的河南连康山国家级自然保护区生态环境质量时空变化研究

基于2013、2017和2021年的Landsat-8 OLI/TIRS影像,计算河南连康山国家级自然保护区的遥感生态指数(RSEI),并结合高程、坡度和坡向等数据探讨RSEI的变化与地形特征的关系。结果表明:(1)研究区2013、2017和2021年的RSEI平均值分别为0.251、0.397和0.597,呈现出逐渐上升态势,生态环境质量持续改善。核心区和缓冲区的生态环境质量不均衡发展趋势加重,实验区则趋于平衡。(2)RSEI变化以轻微改善和显著改善为主,主要集中分布于中部和南部,净改善面积为79.67 km^(2),占比75.30%。(3)中海拔(309~464 m)、坡度5°~35°以及阳坡(南、西南、西、西北)区域是RSEI降低的主要区域,建议加大该区域的保护治理力度,促进保护区生态环境质量的提升。

汾河谷地大气环境容量与大气污染过程的数值模拟与敏感性分析

对汾河谷地及太原市在2015年1月的一次重污染过程运用WRF-Chem模式进行污染过程的数值模拟、观测验证和地形敏感性实验,分析了河谷地形对区域污染过程和大气环境容量的影响机制。结果表明:太原市及周边汾河谷地大气边界层环流和大气污染传输受天气系统、地形和城市化共同影响;地形环流强度明显强于太原城市热岛环流,且对其发展存在明显抑制作用,从而限制了城市大气环境容量,加剧城市近地面大气污染物的堆积和空气质量恶化;研究区域大气环境容量受气象主导风向影响:当天气主导风向偏南北向,也即与狭长的汾河谷地走向一致时,有利于该区域大气污染物的扩散清除,而当天气主导风向偏东西向时,则该区域大气环境容量明显减小,且近地面大气污染物浓度与大气环境容量之间呈强相关性,相关系数达到0.74;当地形敏感组实验中取消太原市周边河谷地形特征时,上述相关系数降低到0.21。

基于三维地形优化的水源保护区划定研究

为保护和合理利用水资源,因地制宜划定饮用水水源保护区,本研究基于三维地形提取水流量和分水岭,优化类比经验法、地形边界法、缓冲区法等传统方法,构建了符合南方丘陵区地形破碎特点的饮用水水源保护区划定方法。并以湖南省武冈市为例开展实证研究,研究结果表明基于三维地形优化的方法可行,结果可靠,对比传统方法精度更高。随着实景三维建设与应用技术的提升,本研究的方法优势将扩大,结果更可行。

废弃露天矿山地质环境特征及生态修复

为了治理和改善研究区矿山生态环境,分析研究区主要矿山地质环境问题,认为其主要问题为地形地貌景观破坏、土地资源破坏等。通过采用场地整理工程、边坡修整工程、废弃建筑物拆除工程、挡土保水岸墙工程、蓄水池工程、排水渠工程、垫渣和覆土工程、植被重建工程、道路工程以及管护工程,使治理区地质灾害体达到安全状态,使生态环境得到一定程度的保护恢复。

矿山环境下的多台无人矿车协同作业调度与协调策略研究

矿山环境的复杂性为多台无人矿车的协同作业调度和协调策略实施带来一系列挑战。基于先进技术,提出一种矿山环境下多台无人矿车协同作业的调度与协调策略,以优化运行效率、提高资源利用率。通过高精度地图构建、自组织通信网络和分布式资源分配等手段,实现无人矿车的智能化协同作业,从而为矿业生产的提升与优化提供技术支持。

三维对象模型与地形的匹配方法研究

提出并详细论述了四点匹配的方法并对该方法中的悬空点计算、姿态突变等问题 ,给出了相应的解决方案 针对点、线、面匹配方法中存在的问题 ,各种方法的效率、质量、适用范围进行了比较 。