透明胞外聚合颗粒物碳输运新途径

目前大家普遍认为,透明胞外聚合颗粒物(Transparent Exopolymer Particles,TEP)因其独特的凝聚效应导致碳通量向海底输出。但是,近几年的研究表明TEP不仅影响了碳沉降途径,其本身能够悬浮甚至向海水表层迁移,导致其在海洋微表层(Surface Micro-layer, SML)积累,最终显著影响海洋表层碳通量。TEP和其他颗粒物聚集形成凝聚物后,其运动趋势则由凝聚物中TEP的含量占比,即最终颗粒物密度所决定。一个新的值得注意的现象是,密度低的TEP通过与其他微粒聚合形成表面活性物质(Surface-active Substances, SAS),会在海洋–大气界面形成薄膜,显著影响海–气CO₂交换通量,甚至对全球气候变化造成影响。     

Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay,Northern South China Sea

Ocean Science Journal - The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of...     

Succession of the Nanoplankton Community during a Brown Tide in a Scallop Culture Area in China

Ocean Science Journal - Brown tides caused by Aureococcus anophagefferens have occurred frequently in the coastal waters of Qinhuangdao since 2009. The Changli coast is the area most strongly...     

旋翼无人机测算风速风向技术研究

目前大部分民用无人机没有准确测量风速、风向和预警风场的功能,然而森林火灾扑救等多种场景需要无人机可以提供准确的风速。本文提出了一种基于旋翼无人机坐标数据测算风速风向的技术,通过无人机主机RTK坐标信息及方位角、倾角数据精准获取螺旋桨点相对坐标信息,选择不同负载条件下无人机以1~16 m/s的不同速度分别飞行30 s以上,根据螺旋桨坐标信息变化数值,结合风洞测试数据及风场动力学原理,研究风速与旋翼无人机倾角关系,并通过风洞试验检验该方法精度;并可根据无人机RTK推算出的螺旋桨坐标变化信息判断风向。结果表明,无人机风速与旋翼无人机倾角呈正相关关系;无人机负载加重时,对应受风速干扰的倾角会相对减小;无人机飞行受阵风干扰出现噪点的概率,高海拔区域大于低海拔区域;并建立六旋翼无人机飞行倾角的风速估算模型y=－1.043 5+1.150 1x,该模型测算风速的中误差值为0.966,绝对值小于1,满足应急指挥现场对无人机测量风速精度要求。该方法得到风速测算精度高,可以为旋翼无人机实时获取风速风向提供一种可行方法,具有一定的实用价值。     

Improved Priority‐Flood method for depression filling by redundant calculation optimization in local micro‐relief areas

Depression filling is a critical step in distributed hydrological modeling using digital elevation models (DEMs). The traditional Priority‐Flood (PF) approach is widely used due to its relatively high efficiency when dealing with a small‐sized DEM. However, it seems inadequate and inefficient when dealing with large high‐resolution DEMs. In this work, we examined the relationship between the PF algorithm calculation process and the topographical characteristics of depressions, and found significant redundant calculations in the local micro‐relief areas in the conventional PF algorithm. As such calculations require more time when dealing with large DEMs, we thus propose a new variant of the PF algorithm, wherein redundant points and calculations are recognized and eliminated based on the local micro‐relief water‐flow characteristics of the depression‐filling process. In addition, depressions and flatlands were optimally processed by a quick queue to improve the efficiency of the process. The proposed method was applied and validated in eight case areas using the Shuttle Radar Topography Mission digital elevation model (SRTM‐DEM) with 1 arc‐second resolution. These selected areas have different data sizes. A comparative analysis among the proposed method, the Wang and Liu‐based PF, the improved Barnes‐based PF, the improved Zhou‐based PF, and the Planchon and Darboux (P&D) algorithms was conducted to evaluate the accuracy and efficiency of the proposed algorithm. The results showed that the proposed algorithm is 43.2% (maximum) faster than Wang and Liu's variant of the PF method, with an average of 31.8%. In addition, the proposed algorithm achieved similar performance to the improved Zhou‐based PF algorithm, though our algorithm has the advantage of being simpler. The optimal strategies using the proposed algorithm can be employed in various landforms with high efficiency. The proposed method can also achieve good depression filling, even with large amounts of DEM data.     

Simulation of landscape spatial layout evolution in rural-urban fringe areas: a case study of Ganjingzi District

In recent years, the rapid expansion of urban spaces has accelerated the mutual evolution of landscape types. Analyzing and simulating spatio-temporal dynamic features of urban landscape can help to reveal its driving mechanisms and facilitate reasonable planning of urban land resources. The purpose of this study was to design a hybrid cellular automata model to simulate dynamic change in urban landscapes. The model consists of four parts: a geospatial partition, a Markov chain (MC), a multi-layer perceptron artificial neural network (MLP-ANN), and cellular automata (CA). This study employed multivariate land use data for the period 2000–2015 to conduct spatial clustering for the Ganjingzi District and to simulate landscape status evolution via a divisional composite cellular automaton model. During the period of 2000–2015, construction land and forest land areas in Ganjingzi District increased by 19.43% and 15.19%, respectively, whereas farmland, garden lands, and other land areas decreased by 43.42%, 52.14%, and 75.97%, respectively. Land use conversion potentials in different sub-regions show different characteristics in space. The overall land-change prediction accuracy for the subarea-composite model is 3% higher than that of the non-partitioned model, and misses are reduced by 3.1%. Therefore, by integrating geospatial zoning and the MLP-ANN hybrid method, the land type conversion rules of different zonings can be obtained, allowing for more effective simulations of future urban land use change. The hybrid cellular automata model developed here will provide a reference for urban planning and policy formulation.     

X-ray activity from different types of stars

X-ray emission is an important indicator of stellar activity. In this paper, we study stellar Xray activity using the XMM-Newton and LAMOST data for different types of stars. We provide a sample including 1259 X-ray-emitting stars, of which 1090 have accurate stellar parameter estimations. Our sample size is much larger than those used in previous works. We find a bimodal distribution of the X-ray to optical flux ratio(log(fX/fV)) for G and K stars. We interpret that this bimodality is due to two subpopulations with different coronal heating rates. Furthermore, using the full widths at half maxima calculated from Hα and Hβ lines, we show that these stars in the inactive peaks have smaller rotational velocities. This is consistent with the magnetic dynamo theory that presumes stars with low rotational velocities have low levels of stellar activity. We also examine the correlation between log(fX/fV) and luminosity of the excess emission in the Hα line, and find a tight relation between the coronal and chromospheric activity indicators.     

检测前跟踪框架下利用蒙特卡洛算法的空间碎片跟踪策略研究（英文）

在轨卫星或者空间碎片数量的增多,是对空间目标地基自动观测的一个挑战。尽管北美防空司令部编目管理了绝大多数直径超过10 cm的空间物体,但由于轨道摄动,空间目标的位置信息(基于6个轨道根数)依然非常重要,并需要定期更新。在过去的几十年里,配备电子传感器的现代地基光电望远镜已广泛用于天体测量领域。然而,这种设备的跟踪性能主要取决于空间目标的大小和亮度。这些目标所在的天文图像会有不同的背景;而且,在基于凝视模式的短曝光实时观测过程中,运动目标和背景恒星在不同的信噪比下显示为类似的点扩散函数,难以辨认。本研究是为了实现对非高斯和动态背景的高灵敏度检测和跟踪能力的提高,并具有简单的系统机制和出色的计算效率。为突破该限制,将重点放在利用状态估计技术对微小卫星和暗弱目标进行跟踪上。提出一种基于神经网络的自适应运行高斯平均算法,用以从恒星背景及干扰下提取运动的空间目标。该方法随后被集成到了一个检测前跟踪框架中。该框架利用基于蒙特卡洛的粒子滤波跟踪空间目标。三段来自亚太地基光学空间目标观测系统(APOSOS)图像序列被用来对该跟踪策略进行评估。实验结果表明,该方法能够达到满意的跟踪性能。     

鲁西地区矽卡岩型铜金矿He—Ar同位素测定及其地质意义——以沂南地区铜井式铜金矿为例

铜井式铜金矿(包括铜井铜金矿、金场铜金矿)是鲁西地区发现和开采最早、矿化最普遍的矽卡岩型铜金矿。该文通过矿床的He-Ar同位素测试分析,并结合前人的H,O,S,C稳定同位素分析和年代学测试结果,对铜井式铜金矿成因及成矿机制进行探讨。研究认为,铜井式金矿主要形成于燕山晚期(128~121Ma),黄铁矿中流体包裹体的~(3 )He/~(4 )He值为0.112 9~0.120 9R/Ra,高于地壳物质值,低于典型地幔物质值;~(40 )Ar/~(36 )Ar=364.1~458.0,高于大气值,低于地幔值,成矿流体中存在来源于地壳的放射成因Ar;~(4 )He/~(40 )Ar=1.16~3.433,平均2.296 5,略高于地幔值(1.36~2.23),低于典型地壳值(6.4),表明成矿流体中存在地幔He,Ar;同时有地壳He,Ar加入。综上认为,矿床成矿物质和流体具有深源特征,应来自地幔或下地壳,金成矿主要是与燕山晚期浅成—超浅成中酸性侵入岩有关,这些侵入体在侵位过程中与古生代碳酸盐岩地层发生接触交代作用,形成矽卡岩型铜金矿床。     

风城油田重油SAGD蒸汽腔微震监测

中国石油新疆油田分公司风城油田1845井区目前有13个井组正在实施蒸汽辅助重力泄油(SAGD).2018年12月至2019年4月期间,我们应用微破裂向量扫描对该井区实施了共35天的微震监测,试图定量确定热蒸汽腔的4D变化.由于微震活动的间歇性和跳跃性,一定期间的监测,很难用含震级或能量的震源分布对蒸汽腔实施解释;故,我...