Effects of N:P ratio of Artemisia ordosica on growth influenced by soil calcium carbonate

Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth of plants on sand land and its mechanism of plant physiology, we performed pot experiments with a two-factor randomized block design and a three-factor orthogonal design for different soil CaCO_3 content treatments using Artemisia ordosica seedlings. In the experiments, we surveyed plant height, aboveground biomass, root length and root weight and analyzed N, P concentrations and RNA content of the seedlings, and discussed the relationships between relative growth rate(RGR) of the seedlings and N:P ratio as well as RNA. Results show that, the RGRs of plant height and above-ground biomass of the seedlings decreased significantly with the increase of soil CaCO_3 content, and those for root length and root weight decreased. The RGRs of plant height and above-ground biomass of the seedlings were significantly negatively correlated with leaf N:P ratios, but significantly positively correlated with leaf RNA content and leaf P concentrations. It can be seen that soil CaCO_3 is a stress factor for the growth of A. ordosica seedlings, and the growth response of the seedlings under the influence of soil CaCO_3 is in line with the Growth Rate Hypothesis.     

库布齐沙漠3种沙产业模式的经济效益评价

库布齐沙漠是中国第七大沙漠,2000-2015年沙产业发展迅速,规模较大。库布齐模式在国内外影响力很大,实现了防沙治沙和生态经济的双赢。但库布齐模式在科学界也存在较大争议,主要表现在库布齐模式的水资源承载力和沙产业的效益评价方面。运用数据包络分析方法（DEA法）评价了库布齐模式中3种沙产业模式2015年的经济效益。结果表明：在3种沙产业模式中,光伏发电综合利用模式和生态旅游模式投入产出综合效率最高,达到1.000,高于生态饲料加工模式的综合效率且3种沙产业模式的纯技术效率均实现DEA有效;3种沙产业模式投入产出规模效率均较高,均值为0.978,最优为光伏发电综合利用模式和生态旅游模式。在此基础上,提出了库布齐模式存在的问题、沙产业今后发展的方向与对策建议。     

辽宁省城市人居环境系统耦合协调度时空格局演变及驱动力研究

人居环境系统内部的耦合协调是保证人居环境均衡发展的基础。基于“人类-居住-支撑-自然-社会”5个子系统,构建人居环境系统耦合协调发展评价指标体系,将2个系统间的容量耦合模型扩展运用到人居环境5个子系统中,综合熵值法、GIS空间分析以及地理探测器对辽宁省2005~2016年人居环境系统耦合协调度的时空演化特征与驱动力进行探讨,阐述人居环境系统内部协调性。研究表明:①2005~2016年辽宁省人居环境系统内部的耦合度与耦合协调度整体呈缓慢浮动上升趋势;②辽宁省人居环境耦合协调度呈分散格局,并且呈现从中间向两侧递减的“屋脊”式格局和“双核结构”;东西方向上,空间演变趋势由倒U型逐渐向一字型演变,南北方向上由斜线型向“L”型演变。③全省出现了中耦合低协调区、中耦合过渡协调区、高耦合低协调区、高耦合过渡协调区、高耦合高协调区5种类型区。④空间分异驱动力主要包括人的需求、经济发展、住房、互联网发展等。     

吉林省村域尺度下居民点空间分布特征及优化重组模式

乡村聚落的空间优化与重构是提高土地资源利用效率,改善农村生产生活条件,促进乡村可持续发展的重要手段。以吉林省为例,采用核密度估计方法和景观形状指数分析了农村居民点空间分布特征,基于农户调查数据估算了吉林省不同区域的农村宅基地闲置情况,将农村居民点长期存在的“破碎化”和日益突出的“空心化”相结合,提出了在行政村尺度下农村居民点优化重组的“整小填大”新模式。结果表明：① 吉林省农村居民点规模小且零散分布,尤其中部呈破碎化分布,形态不规则,具有较大的整治潜力;② 吉林省农村宅基地平均闲置率为18.32%,西部地区最高（24.48%）,分别高于东部和中部地区约6%和12%;③“整小填大”模式可使农村居民点数量减少44.6%,增加有效耕地面积1 046.66 km²。     

Paleogene evolution and demise of the proto‐Paratethys Sea in Central Asia (Tarim and Tajik basins): Role of intensified tectonic activity at ca. 41 Ma

The proto‐Paratethys Sea covered a vast area extending from the Mediterranean Tethys to the Tarim Basin in western China during Cretaceous and early Paleogene. Climate modelling and proxy studies suggest that Asian aridification has been governed by westerly moisture modulated by fluctuations of the proto‐Paratethys Sea. Transgressive and regressive episodes of the proto‐Paratethys Sea have been previously recognized but their timing, extent and depositional environments remain poorly constrained. This hampers understanding of their driving mechanisms (tectonic and/or eustatic) and their contribution to Asian aridification. Here, we present a new chronostratigraphic framework based on biostratigraphy and magnetostratigraphy as well as a detailed palaeoenvironmental analysis for the Paleogene proto‐Paratethys Sea incursions in the Tajik and Tarim basins. This enables us to identify the major drivers of marine fluctuations and their potential consequences on Asian aridification. A major regional restriction event, marked by the exceptionally thick (≤ 400 m) shelf evaporites is assigned a Danian‐Selandian age (ca. 63–59 Ma) in the Aertashi Formation. This is followed by the largest recorded proto‐Paratethys Sea incursion with a transgression estimated as early Thanetian (ca. 59–57 Ma) and a regression within the Ypresian (ca. 53–52 Ma), both within the Qimugen Formation. The transgression of the next incursion in the Kalatar and Wulagen formations is now constrained as early Lutetian (ca. 47–46 Ma), whereas its regression in the Bashibulake Formation is constrained as late Lutetian (ca. 41 Ma) and is associated with a drastic increase in both tectonic subsidence and basin infilling. The age of the final and least pronounced sea incursion restricted to the westernmost margin of the Tarim Basin is assigned as Bartonian–Priabonian (ca. 39.7–36.7 Ma). We interpret the long‐term westward retreat of the proto‐Paratethys Sea starting at ca. 41 Ma to be associated with far‐field tectonic effects of the Indo‐Asia collision and Pamir/Tibetan plateau uplift. Short‐term eustatic sea level transgressions are superimposed on this long‐term regression and seem coeval with the transgression events in the other northern Peri‐Tethyan sedimentary provinces for the 1st and 2nd sea incursions. However, the 3rd sea incursion is interpreted as related to tectonism. The transgressive and regressive intervals of the proto‐Paratethys Sea correlate well with the reported humid and arid phases, respectively in the Qaidam and Xining basins, thus demonstrating the role of the proto‐Paratethys Sea as an important moisture source for the Asian interior and its regression as a contributor to Asian aridification.     

Detecting arbitrarily shaped clusters in origin-destination flows using ant colony optimization

An origin-destination (OD) flow can be defined as the movement of objects between two locations. These movements must be determined for a range of purposes, and strong interactions can be visually represented via clustering of OD flows. Identification of such clusters may be useful in urban planning, traffic planning and logistics management research. However, few methods can identify arbitrarily shaped flow clusters. Here, we present a spatial scan statistical approach based on ant colony optimization (ACO) for detecting arbitrarily shaped clusters of OD flows (AntScan_flow). In this study, an OD flow cluster is defined as a regional pair with significant log likelihood ratio (LLR), and the ACO is employed to detect the clusters with maximum LLRs in the search space. Simulation experiments based on AntScan_flow and SaTScan_flow show that AntScan_flow yields better performance based on accuracy but requires a large computational demand. Finally, a case study of the morning commuting flows of Beijing residents was conducted. The AntScan_flow results show that the regions associated with moderate- and long-distance commuting OD flow clusters are highly consistent with subway lines and highways in the city. Additionally, the regions of short-distance commuting OD flow clusters are more likely to exhibit ‘residential-area to work-area’ patterns.     

污染物排放量增长与经济增长脱钩状态评价研究

污染物排放量增长与经济增长的脱钩本质之一就是污染物排放减量化直至去污化,实现生态与经济的共生.选择废水、化学需氧量、氨氮、二氧化硫和烟尘作为污染物指标,GDP、工业增加值和消费支出作为经济指标,进行脱钩分析.结果表明:1998-2010年,污染物排放量与经济增长脱钩状态总体上处于增长弱脱钩和强正脱钩,但是部分污染物排放量脱钩状态出现短暂的恶化情形.结构性分析发现:生活领域的废水、化学需氧量和氨氮对废水、化学需氧量和氨氮排放总体脱钩影响显著;工业SO2排放直接决定着SO2总量脱钩状态;生活烟尘对烟尘脱钩状态产生扰动性影响.     

柴达木河都兰区植被覆盖率变化特征

柴达木河都兰区位于青海柴达木盆地东南部,干旱少雨,生态环境脆弱。基于MODIS NDVI数据,应用遥感方法,对都兰区2000—2011年的植被覆盖率进行了计算,并分析了其影响因素。结果表明：研究区内裸土和低覆盖率植被的面积逐年减小,而较低覆盖率、中等覆盖率、较高覆盖率及高覆盖率植被的面积均逐年增加;研究区植被覆盖率与降水及相对湿度呈正相关关系,区域植被生长与地下水埋深的关系较为密切;宗加-诺木洪植被区的地下水埋深范围为0.7～3.5 m,在水埋深为1.7 m的地方,植被长势最好;当研究区的地下水水质矿化度小于3 g·L^-1时,植被发育较好。     

Remote Sensing Image On‐Demand Computing Schema for the China ZY‐3 Satellite Private Cloud‐Computing Platform

Time is a crucial factor for many remote sensing applications such as emergency response. The traditional approach requires users to spend a lot of time downloading, processing, and viewing satellite images with specialized software. Realizing interactive real‐time processing and visualization of satellite images online is our focus. This article presents an On‐Demand computing schema for remote sensing images. A processing chain model is proposed for satellite images on a private cloud computing platform designed for the China Centre for Resources Satellite Data and Application (CCRSDA). The architecture, processing flow, optimization method, fault tolerance, and user interface are described in detail. To test the efficiency and scalability of the platform, 11 processing chains were created and three load balance experiments were executed. The results from these experiments show the validity of the proposed methods and architecture.     

伊拉克M油田白垩系Mishrif组潟湖环境碳酸盐岩储集层成因机理

为深化潟湖相碳酸盐岩储集层非均质性认识,以伊拉克M油田白垩系Mishrif组为例,基于岩心观察、物性分析数据、铸体薄片及压汞实验,对潟湖相储集层特征及成因机理开展研究.结果显示:研究区潟湖环境岩石类型复杂,生物碎屑具有多样性,储集层以低渗、特低渗为主,孔隙度分布范围宽,发育大量的基质微孔、铸模孔和晶间孔.储集层强非均质...