适应气候变化的国际行动和农业措施研究进展

针对气候变暖采取稳健的适应措施已成为国际社会共识。该文综合了当前适应气候变化的国际谈判进展及已有的农业适应气候变化措施,指出适应资金严重不足,技术研发、应用与转让难以实施,以及适应气候变化行动实施能力的不足严重制约着适应气候变化行动的有效实施;关于农业适应气候变化的技术措施仍缺乏系统的理论研究与应用示范。在此基础上,提出了未来中国农业适应气候变化需要重点开展的研究任务,即农业气象灾变过程的新特点及其风险管理, 农业适应气候变化的大数据决策管理系统研发及适应气候变化的农业气候区划与减灾保产技术研究,以切实推进农业适应气候变化,为确保国家粮食安全与农业可持续发展提供支撑。     

2001年四川省雅江-康定6.0级地震烈度考察及发震构造背景雏议

2001年2月23日四川省发生的6.0级地震,其宏观震中位于雅江县与康定县之间的高山峡谷地带．极震区烈度可达Ⅷ 度,Ⅷ 度区、Ⅶ 度区和Ⅵ 度区面积分别为180km2,1472 km2和3998 km2,等震线分布总体形态呈椭圆形,长轴近南北向．震区建筑物普遍受损,极震区山地灾害较为严重．初步分析认为,此次地震的发生与理塘断裂和玉农希断裂的长期活动有关,主干断裂活动造成的地壳应力调整和集中,最终在块体内部的次级断裂上释放而产生地震．     

地震动参数速报技术研究

本论文内容涵盖传感器组网,数据获取、存储、管理、迁移与服务,以及地震动参数计算与发布等检测系统各个环节,在研究过程中,以地震动参数速报技术研究为主题,并注意把相关的技术应用在实际的工作中。“基于IPV6对地震烈度传感器网络”部分直接使用了ShakeMap开发过程中有关数据流的接收、服务,操作系统的重编译,事件检测,图片产出,     

阿拉善高原古湖岸堤释光测年与晚第四纪湖面变化

阿拉善高原位于现代西风环流与东亚季风环流过渡带,该地区分布的湖泊对全球性气候变化响应极为敏感,阿拉善高原广泛分布的古湖岸堤为较准确地重建晚第四纪湖泊水位变化提供了良好载体。近年对黑河、石羊河尾闾湖泊以及吉兰泰盐池、雅布赖盆地等地的古湖岸堤的沉积地层以及石英和钾长石释光测年研究,重建了不同区域较高分辨率的末次间冰期以来湖泊时空演化过程。发现早在300 ka以前阿拉善高原就已经形成了高水位湖泊,黑河尾闾额济纳盆地在MIS 11或更早、MIS 9、MIS 7、MIS 5和MIS 1形成了高湖面湖泊,高湖面湖泊形成存在100 ka的周期。阿拉善高原在末次间冰期及全新世形成了稳定高湖面湖泊,但间冰期内部湖面波动具有空间差异性,东部区域湖泊高湖面出现在MIS 5e~5c和中全新世,西部湖泊高湖面出现在MIS 5a~5c和晚全新世。湖面变化的空间差异性很可能与冰期-间冰期旋回尺度及间冰期内部东亚夏季风与西风气候系统在阿拉善高原的相互作用密切相关。

     

Computational model coupling mode II discrete fracture propagation with continuum damage zone evolution

We propose a numerical method that couples a cohesive zone model (CZM) and a finite element‐based continuum damage mechanics (CDM) model. The CZM represents a mode II macro‐fracture, and CDM finite elements (FE) represent the damage zone of the CZM. The coupled CZM/CDM model can capture the flow of energy that takes place between the bulk material that forms the matrix and the macroscopic fracture surfaces. The CDM model, which does not account for micro‐crack interaction, is calibrated against triaxial compression tests performed on Bakken shale, so as to reproduce the stress/strain curve before the failure peak. Based on a comparison with Kachanov's micro‐mechanical model, we confirm that the critical micro‐crack density value equal to 0.3 reflects the point at which crack interaction cannot be neglected. The CZM is assigned a pure mode II cohesive law that accounts for the dependence of the shear strength and energy release rate on confining pressure. The cohesive shear strength of the CZM is calibrated by calculating the shear stress necessary to reach a CDM damage of 0.3 during a direct shear test. We find that the shear cohesive strength of the CZM depends linearly on the confining pressure. Triaxial compression tests are simulated, in which the shale sample is modeled as an FE CDM continuum that contains a predefined thin cohesive zone representing the idealized shear fracture plane. The shear energy release rate of the CZM is fitted in order to match to the post‐peak stress/strain curves obtained during experimental tests performed on Bakken shale. We find that the energy release rate depends linearly on the shear cohesive strength. We then use the calibrated shale rheology to simulate the propagation of a meter‐scale mode II fracture. Under low confining pressure, the macroscopic crack (CZM) and its damaged zone (CDM) propagate simultaneously (i.e., during the same loading increments). Under high confining pressure, the fracture propagates in slip‐friction, that is, the debonding of the cohesive zone alternates with the propagation of continuum damage. The computational method is applicable to a range of geological injection problems including hydraulic fracturing and fluid storage and should be further enhanced by the addition of mode I and mixed mode (I+II+III) propagation. Copyright © 2016 John Wiley & Sons, Ltd.     

重复航空摄影测量方法在乌鲁木齐河流域冰川变化监测中的应用

介绍重复航空摄影测量对比成图方法在监测乌鲁木齐河流域冰川规模和形态要素变化中的应用，以及成图过程中对控制加密和精度等问题的处理。检验表明，航空摄影测量对比成图方法能较准确地量测冰川长度、面积和储量等全形态要素的变化量，可以用于区域冰川变化的监测研究。测量资料表明，１９６４～１９９２年间，乌鲁木齐河流域１５５条冰川的规模均在缩小，冰川末端平均后退率为１２．４％，面积平均缩小率为１３．８％，冰储量减少１５．５％。     

红层地区砂泥岩互层状斜坡岩体流变特性研究

本文在对侏罗系砂溪庙组砂，泥岩进行的系统流变试验的基础上，详细研究了砂，泥岩的流变特性及其相应的长期强度，以及砂，泥岩互层状组成的斜坡碉体流变特征，特别是模拟研究了风化深度较厚的泥岩产生的粘塑性流动对斜坡应力场及斜坡变形破坏所起的不可忽视的作用。     

辽河三角洲滨海湿地水域初级生产力研究进展

滨海湿地位于海洋与陆地生态系统的交错过渡带,具有极高的生产力和光合固碳效率,是海岸带蓝色碳汇的重要组成部分。滨海湿地生产力不仅由芦苇、翅碱蓬、红树林等陆上植被提供,水体中浮游植物的光合固碳也是提供初级生产力的重要途径。以往较多的调查和研究集中在陆上植被,而对于滨海湿地水域浮游植物和底栖微藻的报道较少。近年来随着各国政府和学者对二氧化碳排放和气候变化的关注,滨海湿地多圈层生态系统的碳循环和碳汇过程成为研究热点,而湿地水域生产力和光合固碳过程作为多圈层碳循环中重要的一个环节亦应受到足够的重视。以中国北方典型的盐沼湿地区域——辽河三角洲滨海湿地为案例,对湿地水域生产力研究进展进行综述,并对其影响因素进行讨论,以期为国家碳循环与碳中和目标调查提供参考资料。     

Hydrothermal plume mapping as a prospecting tool for seafloor sulfide deposits: a case study at the Zouyu-1 and Zouyu-2 hydrothermal fields in the southern Mid-Atlantic Ridge

Seafloor hydrothermal polymetallic sulfide deposits are a new type of resource, with great potential economic value and good prospect development. This paper discusses turbidity, oxidation–reduction potential, and temperature anomalies of hydrothermal plumes from the Zouyu-1 and Zouyu-2 hydrothermal fields on the southern Mid-Atlantic Ridge. We use the known location of these vent fields and plume data collected in multiple years (2009, 2011, 2013) to demonstrate how real-time plume exploration can be used to locate active vent fields, and thus associated sulfide deposits. Turbidity anomalies can be detected 10 s of km from an active source, but the location precision is no better than a few kilometers because fine-grained particles are quasi-conservative over periods of many days. Temperature and oxidation–reduction potential anomalies provide location precision of a few hundred meters. Temperature anomalies are generally weak and difficult to reliably detect, except by chance encounters of a buoyant plume. Oxidation–reduction potential is highly sensitive (nmol concentrations of reduced hydrothermal chemicals) to discharges of all temperatures and responds immediately to a plume encounter. Real-time surveys using continuous tows of turbidity and oxidation–reduction potential sensors offer the most efficient and precise surface ship exploration presently possible.