黄河三角洲新生湿地土地覆被演替图谱

本文根据黄河三角洲新生湿地盐生、湿生、中生以及人工等不同生境的生态景观类型 ,将本区土地覆被类型分为 9类 ,即研究区海域、滩涂、柽柳 -翅碱蓬群落、獐毛 +白茅群落、芦苇 +荻群落、有林地、天然河流与人工水体、耕地和居民工矿用地。从遥感影像数据 (包括LandsatTM432、CBERS 1CCD432 )和专题矢量数据中提取了 1 984、 1 991、 1 996和 2 0 0 0年四期土地覆被数据 ,采用区域质心函数计算四个时期 9类覆被的分布重心 ,并合成土地覆被重心演替过程图谱 ,通过图谱分析 ,归纳出湿地植被演替的三种模式 ,即陆进模式、海退模式以及人类活动影响模式 ,为认识新生湿地植被演替规律以及人类活动的影响、制定湿地保护措施提供参考依据。     

2017年西藏米林MS6.9地震发震构造初探

2017年11月18日在西藏米林发生了M_S6.9地震,目前尚未发现地表破裂带,发震构造尚不明确.震源机制解表明该次地震为逆冲型地震.精定位结果显示余震集中在加拉白垒东北坡上一个NW走向的长约36 km、宽约8 km的狭长条带之内.余震条带的走向及长度严格受到派乡构造岩片NE边界走向及长度的控制,垂直于该条带的地震剖面清晰地揭示出一条倾向NE的低倾角逆冲断层面,结合震源机制解及GPS同震位移场的已有结果,初步推断它可能就是发震断层面.雅鲁藏布江大拐弯上游加拉-米林河段两岸的湖相基座阶地面和山脊线在南迦巴瓦、加拉白垒脚下都发生了倾向SW的翘起变形,发震断层面构成了其上盘加拉白垒、南迦巴瓦强烈隆升区与其下盘地貌发生翘起变形的弱隆升区的分界面,推断加拉白垒峰沿着这一断层面不断地逆冲、隆升,以此来调节其两侧的不均匀挤出,而下盘近断层处的褶皱、拖曳等作用逐渐造成了阶地面、山脊线的翘起、弯曲变形.基于夷平面的区域变形分析,认为雅江缝合带作为主干断裂带从整体上控制着印度板块与欧亚板块在东构造结地区的碰撞-挤压格局.印度板块东北犄角的强烈顶撞引起了东构造结附近强烈的断块运动,嘉黎断裂带北侧的地壳显著增厚,主夷平面随之发生裂解.与此同时,由于碰撞带来的强烈挤压,派乡构造岩片、多雄拉变质穹隆沿着缝合带大拐弯内侧不均匀地挤出,南迦巴瓦、加拉白垒随之隆升.此次的米林地震仅仅是该不均匀挤出过程所引发的一次具体的事件,是派乡构造岩片内部的一条次级断层发生的一次逆冲运动造成的.此外,紧邻此次余震条带的南迦巴瓦NEE边界以及SE边界是一个潜在的地震空区,其未来地震危险性值得关注.

     

现代黄河三角洲地区地面沉降的机理分析

利用前人在现代黄河三角洲地区进行的大量的野外调查和研究结果,对黄河三角洲地面沉降与第四系沉积体系、构造之间的对应关系进行了研究。研究结果表明现代黄河三角洲地区地面沉降除了因人类活动导致地面缓慢沉降外,新构造运动、第四系沉积相的分布也与三角洲沉降存在很好的相关性。研究区沉降区域的分布与主要断裂带相对应,软土的分布基本上控制了主沉降区的边界。研究结果可为以后三角洲的开发利用和管理以及其他三角洲地面沉降或地质灾害的监测提供必要的基础资料。     

A multi-scale study on land use and land cover quality change: The case of the Yellow River Delta in China

This paper presents a case study of the Yellow River Delta in China, to trace land use and land cover changes during the past 20 years, with an emphasis on land quality changes. Three sets of data are used in this case study: remote sensing data derived from satellite images; crop yield data from statistics; and soil data collected by the researchers in the field. Our study reveals that at the regional scale, LUCC has taken place in a positive direction: vegetation cover has been expanding and crop yields per hectare have been on rise. However, while the overall eco-environment has improved, the improvement is uneven across the Delta region. At local levels, some areas show signs of increased salinization and declining organic content. Both natural forces and human activities are responsible for the LUCC, but human activities play a more important role. While some impacts of human activities are positive, the damages are often long-lasting and irreversible. We also conclude that it is necessary to use both macro data (such as remote sensing data) and micro data (data collected in the field) to study land quality change. The former are efficient in examining land quality changes at the regional scale, the latter can serve to verify ground patterns revealed from macro data and help to identify local variations, so as to get a comprehensive understanding of LUCC and promote sustainable land use and land management. This revised version was published online in July 2006 with corrections to the Cover Date.     

九龙江-河口表层水体营养盐含量的时空变化及潜在富营养化评价

分别于2012年9月、2013年1、6月,对九龙江两大支流北溪、西溪及河口区开展了3个航次的营养盐监测.研究结果表明,河口区表层水体溶解无机氮（DIN）、总磷（TP）和活性磷酸盐（PO4-P）质量浓度范围分别为0.13-17.35、0.14-1.00和0.00-0.38 mg/dm3,受上游输入和海水稀释作用,营养盐浓度由淡水端至海水端逐渐降低.北溪表层水体的DIN、TP和活性磷酸盐质量浓度范围分别为1.99-24.92、0.12-1.47和0.04-0.68 mg/dm3,受龙岩地区工农业生产及城市进程影响,由上游至下游逐渐降低.西溪表层水体的DIN、TP和活性磷酸盐质量浓度范围分别为2.74-20.61、0.14-0.92和0.02-0.37 mg/dm3,受上游农业生产和下游漳州地区人类活动影响,上下游的DIN质量浓度较高.此外,九龙江沿岸的人类活动可能影响了该地区水体中的溶解无机氮形态组成：北溪和西溪上游的NH4-N和NO3-N占比分别较高.水期分析表明,2013年1月的DIN浓度显著高于其他水期,而不同区域TP和活性磷酸盐的水期波动不尽相同.营养盐结构分析表明,九龙江总体处于磷限制状态,但在河口及北溪部分站位,CDIN/CPO4-P比值已达到适合浮游生物生长繁殖的水平.潜在富营养化程度评价表明,九龙江河口多数站位均处于N或P限制的富营养化级别,但由于N、P营养盐的绝对浓度较高,具有水华暴发的潜在风险.     

珠江口水域微表层中的痕量金属

采用自制滚筒式自动采样器采样，研究了珠江口水域微表层中Ｆｅ，Ｍｎ，Ｃｕ，Ｐｂ，Ｚｎ，Ｃｄ的含量、分布变化及富集状况。并通过颗粒痕量金属／颗粒Ｆｅ比值计算，探讨了痕量金属的来源。结果表明：Ｃｕ，Ｐｂ，Ｚｎ，Ｃｄ在微表层的平均富集系数分别为２．３，１．４，３．０和１．９。颗粒态Ｆｅ，Ｍｎ的平均富集系数为１．１和０．９。各种金属有明显的季节和空间变化，有各种不同的来源。     

Thermal and tectonic evolution of the southern Alps (northern Italy) rifting: Coupled organic matter maturity analysis and thermokinematic modeling

The Pearl River Mouth Basin (PRMB) is one of the most petroliferous basins on the northern margin of the South China Sea. Knowledge of the thermal history of the PRMB is significant for understanding its tectonic evolution and for unraveling its poorly studied source-rock maturation history. Our investigations in this study are based on apatite fission-track (AFT) thermochronology analysis of 12 cutting samples from 4 boreholes. Both AFT ages and length data suggested that the PRMB has experienced quite complicated thermal evolution. Thermal history modeling results unraveled four successive events of heating separated by three stages of cooling since the early Middle Eocene. The cooling events occurred approximately in the Late Eocene, early Oligocene, and the Late Miocene, possibly attributed to the Zhuqiong II Event, Nanhai Event, and Dongsha Event, respectively. The erosion amount during the first cooling stage is roughly estimated to be about 455–712 m, with an erosion rate of 0.08–0.12 mm/a. The second erosion-driven cooling is stronger than the first one, with an erosion amount of about 747–814 m and an erosion rate between about 0.13–0.21 mm/a. The erosion amount calculated related to the third cooling event varies from 800 m to 3419 m, which is speculative due to the possible influence of the magmatic activity.     

地质灾害的非线性数据处理与建模技术

本文简略地介绍了几种地质灾害数据处理与建模的非线性方法,主要包括GMDH自组织建模技术、神经网络方法。GMDH是一种高阶非线性回归建模方法,它是以简单的二元二次回归方程为基础,通过"代复一代"的"生产"过程,客观、自动地求得实际资料的非线性模型。而神经网络则是用工程技术手段模拟生物神经网络的结构特征和功能特征的一类人工系统。与常规统计方法相比,神经网络最突出的优点为它是通过对网络的学习和训练,来掌握变量之间的非线性关系。因此,其处理复杂问题的能力更强大。实例检验效果表明,这些非线性数据处理与建模技术考虑了地质灾害问题的非线性特性,其比基于常规统计理论的数据处理方法的精度要高得多。     

Habitat use and preference of adult pike (Esox lucius L.) in an anthropogenically impacted lowland river

To efficiently manage northern pike (Esox lucius), information is needed on its habitat use and preference. However, knowledge gaps still exist, especially on pike habitat use and preference in rivers characterised by artificial environments. We investigated the use of the main river, tributaries and side arms at the macro-scale, and the use and preference of riparian habitats by adult pike at the meso-scale in an anthropogenically impacted river basin. Adult pike were followed in winter and spring by radio telemetry. At the macro-scale pike intensively used the main river in winter and spring, but also frequented specific side arms in winter and specific tributaries in spring, which may indicate the importance of these habitats to adult pike. At the meso-scale, reedy semi-natural banks were used the most, irrespective of any assumption on habitat availability or use. The findings underline the value of protecting the least impacted, (semi)natural habitats for adult pike in an anthropogenically impacted river system. The large behavioural differences in habitat use between individuals at both habitat scales further underline the importance of habitat heterogeneity. The results also provide insight into the impact of riparian habitat restoration on adult pike and may be used to more efficiently manage pike rivers, e.g. by enhancing the lateral connectivity with river side arms or by reconstructing natural riparian habitats.     

农业科技园技术扩散的机制与模式研究——以杨凌示范区为例

农业科技园是我国农业技术创新的重要源头和崭新模式,园区不仅要解决自身发展问题．而且肩负着技术扩散和推广的使命。通过技术创新一中介平台一技术受体之间关系的分析,构建了农业科技园技术扩散系统,分析了园区技术扩散的动力机制和主要类型,并以杨凌示范区为例．归纳和总结出市场经济条件下农业科技园技术扩散的成功模式,以图为我国农业科技园的技术扩散和持续发展提供借鉴。