A numerical study of tidal asymmetry: preferable asymmetry of nonlinear mechanisms in Xiangshan Bay,East China Sea

In-situ measurements in Xiangshan Bay, the East China Sea, show that the duration of the rising tide is shorter than that of the falling tide around the bay mouth, while it becomes much longer in the inner bay. A finite volume coastal ocean model (FVCOM) with an unstructured mesh was applied to simulate the asymmetric tidal field of Xiangshan Bay. The model reproduced the observed tidal elevations and currents successfully. Several numerical experiments were conducted to clarify the roles of primary mechanisms underlying the asymmetric tidal field. According to the model results, the time-varying channel depth and nonlinear advection prefer shorter duration of the rising tide in Xiangshan Bay, while the time-varying bay width favors longer duration of the rising tide. The overtides generated by these two opposite types of nonlinear mechanisms are out of phase, resulting in smaller M₄ amplitude than the sumfold of each individual contribution. Although the bottom friction as a nonlinear mechanism contributes little to the generation of overtide M₄, it is regarded as a mechanism that could cause a shorter duration of the rising tide, for it can slow down the M₂ phase speed much more than it slows down the M₄ phase speed. The time-varying depth, nonlinear advection and bottom friction are dominating factors around the bay mouth, while the time-varying width dominates in the inner bay, causing the tidal elevation asymmetry to be inverted along the bay.     

Optimizing hotspot areas for ecological planning and management based on biodiversity and ecosystem services

The significance of biodiversity and ecosystem services are gradually recognized by human as an approach towards sustainability, so it is important to understand relationships and congruence between them to support conservation planning, especially in the hotspot areas with a prominent role in conservation. However, the management of most conservation hotspots mainly focused on biodiversity, and rarely concerned with ecosystem services. With the aim of proposing criteria for conservation strategies that contribute to the optimization of biodiversity and ecosystem services, in this study, a Geographic Information System(GIS)-based approach was designed to estimate and map the biodiversity and ecosystem services in Chongqing Municipality of China. Furthermore, the distributions of hotspot areas for biodiversity and ecosystem services were mapped based on the relationship between cumulative ecosystem services and areas. Finally the statistical analysis was processed focused on specific conservation objectives. The results showed that hotspot areas can conserve the most biodiversity but with the least ecosystem services under the conservation plans target to biodiversity conservation. In contrast, depending on the ecosystem services of interest, hotspot areas can conserve the largest ecosystem services but with the least biodiversity. By integrating biodiversity and ecosystem services into conservation plan, we found that the conservation and regeneration of these small areas, would contribute to a conservation of 44% of the biodiversity hotspot and 14%–42% of the ecosystem services hotspot. Moreover, the current nature reserve selection was not maximize the biodiversity and ecosystem services compared to integration strategy, indicating that hotspot areas conservation and selection is vital for optimization protection of biodiversity and ecosystem services, and has practical significance for natural resources and ecosystem management.     

从滇黔桂“金三角”区域地层地球化学演化特征探讨卡林型金矿的物质来源

选用滇黔桂地区东经103°～110°,北纬22°～26°,面积约20万km2,34幅1∶20万水系沉积物统计结果资料,全面系统地探讨本区及其邻近区域地层地球化学特征及其与成矿的关系。结果表明:(1)与华南地区相比,本区存在Sb、As、Au、Hg等低温元素矿集区的地球化学块体,金具有深源性,而砷、锑、汞则是区域性的高背景,本区金与砷、锑、汞的相伴,既有必然性,又有偶然性;(2)与基性岩浆活动有关的亲基性场元素、氧化物、矿化剂高背景的形成,是本区右江裂谷带、富宁—关岭南北向断裂带、文山—富宁逆冲推覆构造带,特别是峨眉地幔柱所产生的基性岩浆喷溢及火山碎屑浊流沉积的客观地球化学反映;(3)黔西南地区二叠纪峨眉山玄武岩喷发导致二叠系和三叠系金及大量亲基性场元素的突变,右江裂谷活动至少始于寒武纪,随着时间的推移,由桂西往黔西南逐渐裂开;(4)滇黔桂"金三角"地区卡林型金矿的物源与裂谷、特提斯和区域性深大断裂和峨眉地幔柱长期活动相伴的基性火成岩及火山碎屑浊流沉积有关。     

变质矿物生长的局部平衡体系——以贺兰山北段孔兹岩系为例

贺兰山北段孔兹岩系详细的岩石学和矿物学的研究表明 ,岩石中的特征变质矿物如石榴子石、堇青石等的成分与其周围相邻的同世代变质矿物具有很好的相关性 ,而与其寄生主岩成分的相关性较小 ,而贯通矿物如斜长石却与其寄生主岩成分的相关性较为密切 ,同时天然块状样品的脱水熔融实验的结果也显示 ,变质反应是在一个局部平衡体系中进行的。说明在变质作用过程中 ,变质反应的进行以及新矿物的形成是在一个局部平衡的体系下完成的 ,因此在矿物对温压计的使用上 ,应利用处于平衡状态的相邻变质矿物来计算。     

Advances in lunar exploration detectors

Due to the rapid development of modern science and technology, many advanced sensors have been put into use to explore our solar system, including the Moon. With the help of those detectors,we can retrieve more information to about the Moon‘ s composition and evolution. The Clementine (January, 1994), Lunar Prospector (January, 1998) and especially Smart-1 ( September, 2003) launched successively have demonstrated the next-generation planet exploration techniques. Now China has decided to send a probe to the Moon. So it is necessary to overview the development of detectors used for the scientific observation of the Moon. In this paper, some main instruments used to acquire geochemistry information are described, which include UV-VIS-NIR CCD imaging spectroscope, neutronray, gamma-ray, and X-ray spectrometers. Moreover, the payloads of China‘ s first lunar satellite are introduced briefly.     

中国地震预报论坛2021年度学术交流暨中国地震学会地震预报专业委员会委员换届大会在云南大理召开

中国地震学会地震预报专业委员会和云南省地震局于2021年9月13—17日在云南省大理市联合举办了中国地震预报论坛2021年度学术交流暨第十届地震预报专业委员会委员换届大会,来自全国地震行业内外的27个单位的89名代表参加了此次大会。学术交流设置了8个专题;会前征集到论文113篇,会期交流报告40篇,其中口头报告21篇,张贴展板19篇;21篇口头报告中,大会特邀报告1篇;从19篇张贴报告中,评选出优秀报告6篇,最佳设计创意报告1篇。大会按照惯例举行了以“临震的过程特征、信号捕捉、异常提取与临震预报的瓶颈问题”为主题的圆桌讨论。大会闭幕式后还特别针对本次会议中来自行业内外的各种预报方法涉及的相关问题组织了跨学科融通式讨论。充分而积极的讨论不仅增加了行业内外地震预报科研工作者的了解,同时,在对强震临震预测瓶颈问题与突破瓶颈问题途径方面达成了共识：以中国地震科学实验场为平台,以多学科多方法长期实践积累的资料与模型、实验、理论相结合,利用大数据和人工智能方法,不断推动强震临震预报技术瓶颈问题的解决。按照中国地震学会的要求,完成了中国地震学会地震预报专业委员会第十届委员换届,对到会的委员代表颁发了聘书。大会不仅重视学术交流,还兼顾了科学传播的普及,利用当地的科普资源,因地制宜地组织了永胜古地震破裂遗址的现场科普学习;利用中国地震科学实验场大理中心科普馆的有利条件组织了对地震观测技术发展历程的学习,对日常分析预报资料的来历有了更加深入的理解,强化了学术交流的效果。     

Data Fusion Technique for Multibeam Echosoundings

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Adsorption and desorption characteristics of ammonium in eight loams irrigated with reclaimed wastewater from intensive hogpen

There are many reports of NO₃ ^? violating safety standards in the neighboring areas of concentrated animal feeding operations (CAFOs), which have become the bottleneck of the CAFOs development. The high concentration of ammonium nitrogen (NH₄ ⁺-N), which transforms into nitrate nitrogen (NO₃ ^?-N) through nitrification, and then leaches into the groundwater, is a potential threat to the environment. Adsorption and desorption characteristics of ammonium can reduce the amount of NH₄ ⁺-N in soils, which effectively prevents or slows down the nitrate leaching. Researches on the adsorption and desorption of ammonium mainly focus on the simple NH₄ ⁺ solution. Researches on the adsorption and desorption from hogpen wastewater are few, which is a complex system coexisting with many ions. In this paper, ammonium was selected as the object of pollutant, a batch of equilibration experiments was conducted to evaluate the adsorption–desorption and its kinetics in eight loams, typically found in Northern China, irrigated with original wastewater (OW) and reclaimed wastewater (RW) from intensive hogpen and a simple one consisting of clean water (CW). This study showed that the Freundlich and Langmuir model described the ammonium adsorption properties very well in multi-ion coexistensive system of hogpen wastewater; the ammonium adsorbed amount in the corresponding matrices followed by OW < RW < CW tendency, although the adsorption model parameters had great diversity. The adsorbed amount increased as the adsorption time went on and then approached to a stable state. CW had the shortest reaction time to reach equilibrium, whereas OW had the longest. The normal adsorption kinetics equation could not depict the adsorption behavior of loams but characterized by the ExpAssoc equation well. The study could provide references for the wastewater treatment and recycling, and rural water pollution controlling.     

基于LSTM网络的在线藻类时序数据预测研究:以三峡水库为例

三峡水库在不同水位调控期支流回水区末端水深变化幅度较大,加之复杂水动力变化产生的生境异质性,塑造出有别于浅水湖泊的水华暴发特征.本研究基于库区4条支流——香溪河、澎溪河、大宁河及草堂河部署的自动监测数据,利用小波变换(WT)和长短期记忆网络(LSTM)构建藻类时序变化预测模型,并探讨神经网络层数、每层隐藏神经元数、时间...