武汉居民建筑物碳排放反演计算和时空分析

居民建筑物（民用住宅建筑物）碳排放对节能减排策略制定及城市可持续发展具有重要影响。针对目前城市碳排放计算方法尺度较大且缺乏居民建筑物碳排放一致性计算的问题,本文提出一种多源数据融合的城市居民建筑物碳排放定量计算方法。该方法首先采用自上而下的策略,结合夜间灯光图像,将武汉市居民碳排放总量分配到每个地块;然后采用自下而上的策略,构建由地块规划因子、社会经济因子以及单体居民建筑物形态因子组成的居民建筑物碳排放反演模型。论文使用该方法计算了武汉市所有单体居民建筑物的电能消耗碳排放量,研究结果表明：① 居民建筑物碳排放量在空间分布上呈现由中心城区向郊区不断递减的模式,和人口分布有着密切的关系;② 居民建筑物碳排放量分布具有异质性,呈现出长尾分布的特性,其中89%的居民建筑物的碳排放量低于平均值1.28 t,而11%的居民建筑物的碳排放量高于平均值;③ 同一地块上的居民建筑物碳排放量差异相对较小,地块之内平均标准差为7.66 t,而不同地块上的居民建筑物碳排放量差异相对较大,地块之间平均标准差达到51.30 t;④ 居民建筑物的碳排放量更容易受到规划因子中的容积率影响,社会经济因子中的人口密度影响,以及居民建筑物形态类型的影响。论文研究方法及相关研究成果可以为城市居住区可持续规划等问题提供决策支持。     

Effects of organic carbon consumption on denitrifier community composition and diversity along dissolved oxygen vertical profiles in lake sediment surface

At present, the understanding of the dynamics of denitrifiers at different dissolved oxygen (DO) layers under organic carbon consumption within the surface sediments remains inadequate. In this study, high-throughput sequencing and quantitative PCR targeting nirS gene were used to analyze the denitrifier abundance dynamics, community composition, and structure for aerobic (DO 0.5–6.9 mg/L), hypoxic-anoxic (DO 0–0.5 mg/L), and anoxic (DO 0 mg/L) layers in surface sediments under organic carbon consumption. Based on the analysis of nirS gene abundance, the values of denitrifying bacteria decreased with organic carbon consumption at different DO layers. When the bacterial species abundance at the genus level were compared between the high-carbon and low-carbon sediments, there was significant increase in 6 out of 36, 7 out of 36 and 6 out of 36 genera respectively for the aerobic, hypoxic-anoxic and anoxic layers. On the other hand, 14 out of 36, 9 out of 36 and 15 out of 36 genera showed significant decrease in bacterial species abundance respectively for the aerobic, hypoxic-anoxic and anoxic layers. Additionally, 14 out of 36, 20 out of 36, and 15 out of 36 genera had no change in bacterial species abundance respectively for the aerobic, hypoxic-anoxic, and anoxic layers. This indicates that the carbon utilization ability of different denitrifiers on each DO layers was generally different from each other. Diversity of denitrifying bacteria also presented significant differences in different DO layers between the high- and low-carbon content sediment layers. Moreover, under the high-carbon and low-carbon content, the abundance of nirS gene showed a high peak within the hypoxic-anoxic regions, suggesting that this region might be the main distribution area for the denitrifying bacteria within the surface sediments. Furthermore, community of unique denitrifiers occurred in different DO layers and the adaptive changes of the denitrifier community followed the organic carbon consumption.     

3D tree modeling from incomplete point clouds via optimization and L1-MST

Reconstruction of 3D trees from incomplete point clouds is a challenging issue due to their large variety and natural geometric complexity. In this paper, we develop a novel method to effectively model trees from a single laser scan. First, coarse tree skeletons are extracted by utilizing the L₁-median skeleton to compute the dominant direction of each point and the local point density of the point cloud. Then we propose a data completion scheme that guides the compensation for missing data. It is an iterative optimization process based on the dominant direction of each point and local point density. Finally, we present a L₁-minimum spanning tree (MST) algorithm to refine tree skeletons from the optimized point cloud, which integrates the advantages of both L₁-median skeleton and MST algorithms. The proposed method has been validated on various point clouds captured from single laser scans. The experiment results demonstrate the effectiveness and robustness of our method for coping with complex shapes of branching structures and occlusions.     

Intraseasonal Variations of Summer Convection over the Tibetan Plateau Revealed by Geostationary Satellite FY-2E in 2010–14

Based on the infrared black body temperature (TBB) observed by the geostationary meteorological satellite FY-2E from 2010 to 2014, the seasonal migration, occurrence frequency, and intraseasonal variability of summer convection over the Tibetan Plateau (TP) and its surrounding areas are analyzed. The results show that in May, convection mainly occurs over the eastern edge of the TP;in June, following the onset of the Asian summer monsoon, the strongest (severe) convection occurs in the southeastern part of the TP;and in July-August, strong southwesterly winds transport abundant moisture to the eastern and central areas of the TP, leading to formation of an active convection belt over southeastern TP. The results also show that in the western TP, the area with convection frequency greater than 6% occupies the southern plateau around the 37th pentad, and gradually moves northward until the end of July;in the central plateau, convection (severe convection) becomes active since early (mid) June, and maintains through the entire late summer with three major northward movements until reaching 34°N;and in the eastern TP, the convection is relatively active since the beginning of May and its northward stretching is slightly later than that over the central plateau. Overall, summer convective activities are unevenly distributed over the TP, with frequency of convection decreasing from south to north;and they also exhibit considerable intraseasonal variability, the maximum of which is found over the middle reach of the Yarlung Zangbo River and the southeastern plateau. EOF analysis of summer convection frequency over the TP reveals two leading modes, with the first mode being a dipole variation pattern between the Indian monsoon region and the southeastern TP, and the second mode a tripole pattern over the western TP, the Indian continent west of 80°E, and the South Asian continent east of 80°E.     

A Review on Hydraulic Fracture Height Growth for Layered Formation

Geotechnical and Geological Engineering - The fracture vertical stretching distance and fracture morphologies have great impact on the stimulated reservoir volume and well production in layered...     

Himawari-8静止气象卫星时序法火点探测

随着新一代静止气象卫星的发射,高频次和高时效的观测特性对于火点探测具有独特优势。本文基于Himawari-8新一代静止气象卫星高频次观测特点,提出有利于火情初期火点判识的时序探测方法。与传统的极轨气象卫星遥感火情监测采用的上下文法不同,时序探测法判识火点的方法依据为探测像元亮温在观测时间上的差异。研究结果显示,在无云及无异常热源条件下,相邻时次中红外亮温差异较小,当前后时次亮温差达到3K时,可判识出火点,而上下文法的阈值均在6 K以上,时序法的火点判识阈值较上下文法明显降低,探测相应的亚像元火点面积减小一倍以上,从而提高了火情判识的灵敏度,实现火点早期发现。本文介绍了时序法火点判识方法,并以黑龙江桦川县的星地同步观测实验进行验证,研究表明,时序法较上下文法在初发火点探测灵敏度方面有明显优势,时序法和上下文法的结合可提高气象卫星对火情发展过程的监测能力。     

中国梭螺科一新记录属

本研究记述了采集自海南陵水海域的梭螺科(Ovulidae)一新记录属：舟梭螺属(Naviculavolva)及一新记录种：折唇舟梭螺(N.deflexa),对标本进行了形态描述并附标本照,且通过比对样品的COⅠ基因序列证实了形态鉴定的准确性。本研究为梭螺科分类与研究提供参考资料,丰富了我国海域梭螺科物种的多样性,并使得折唇舟梭螺的分布范围延伸至海南省海域。     

旋转多基线对工业摄影测量精度的影响

在工业摄影测量中,影响测量精度的要素较多,为了提高摄影测量精度,在控制网型、被测物体、摄影距离等其它条件相同的情况下,采用不同的工业摄影测量相机,研究每个摄站不同旋转基线次数对精度的影响.通过对比不同旋转基线个数工况下的测量重复性,得出16个相机旋转基线比传统的2个相机旋转基线的测量重复性精度有明显提高;且随着相机旋转...     

从断层擦痕反演的郯庐断裂带南段合肥盆地白垩纪构造应力场

本文通过断层擦痕应力场反演方法,对郯庐断裂带南段合肥盆地白垩纪伸展活动进行了详细研究,厘清了郯庐断裂带南段合肥盆地白垩纪拉伸方向的演变规律。研究结果显示：从早白垩世早-中期、晚期到晚白垩世,拉伸方向由NWW-SEE向、NW-SE向到近SN向转变,具顺时针旋转特征。与西太平洋区大洋板块运动方向对比分析认为：郯庐断裂带南段合肥盆地白垩纪伸展活动发生在弧后拉张的动力学背景下,拉伸方向的演变可能是西太平洋区大洋板块运动方向改变的结果。