象山港海域分区评价方法研究

文章根据2011-2018年在象山港海域调查的象山港水文、水团、水环境、沉积物环境、生物生态等调查数据,将象山港海域划分为若干个具有不同生态变化特征的区域,研究象山港海域内的空间异质性,以便剖析各区域环境的问题。研究发现：象山港水交换特征、水团分布、水环境、沉积环境和生物生态特征将象山港划分为A、B、C、D、E 5个区评价较为合理。该方法可以有效并合理地对象山港海域做出评价,并为相关海洋科学工作者和管理者提供科学依据。     

基于GIS/RS的海岸带生态环境变化研究综述

近年来,随着沿海地区经济建设的脚步的不断加快,人们逐渐加大了对海岸带环境资源的开发利用。海岸带填海造陆、滩涂围垦等人类活动的增多使得区域生物及非生物物质发生了剧烈的改变,进而对海岸带生态环境产生了重要的影响。基于此,各国学者尝试通过一系列的技术手段与方法模型对海岸带生态环境时空变化进行相关探究。其中,遥感与地理信息系统技术作为生态环境的重要分析工具,在区域生态环境变化的评估与监测中有着较为广泛的应用。在海岸带生态环境变化的探究中,由于研究目的、角度以及方向的不同,相关学者所使用的研究方法及模型也存在着一定的差别。本文结合海岸带生态环境研究现状,将海岸带生态环境变化研究分成海岸带土地利用/覆被变化研究、景观格局变化研究、海岸线变迁变迁研究、植被变化研究、水土环境表征因子变化研究以及基于指标体系的生态环境变化研究6个主要部分,并分别从这6个部分出发,对海岸带生态环境变化研究的技术、方法与模型进行归纳总结,从而提出未来我国海岸带生态环境变化研究中需要解决的问题以及重点研究方向,为今后海岸带生态环境的深入研究打下坚实的基础。     

基于景观格局变化的海岸带生态风险评价——以辽宁省瓦房店市为例

文章利用RS和GIS技术手段对辽宁省瓦房店市1990—2015年的变迁过程进行监测,得出各历史时期的土地利用变化信息。将各类土地利用信息与景观生态学相结合,利用景观格局破碎度、景观分离度、景观优势度作为指标构建景观损失指数,并利用景观组分的面积比重构建海岸带生态风险指数。基于ArcGIS和Fragstats软件平台,通过空间采样和插值方法得到区域生态风险的空间分布,据此重构了瓦房店市1990—2015年的生态风险值变化过程。监测表明,1990—2015年期间,耕地、林地和滩涂呈减少趋势,水域和建设用地逐年增加,其他类型变化幅度不大。虽然耕地所占总面积比例由45.37%减少至37.23%,但一直是瓦房店最主要的景观。25年间瓦房店生态安全总体呈下降态势,1990—2015年6时段的生态风险年平均值分别为0.211 9、0.200 3、0.203 2、0.194 9、0.209 7和0.209 1。在时间维度,1990—2005年和2010—2015年生态安全度下降明显;在空间维度,瓦房店市海岸带的李官镇-三台满族乡和谢屯镇-炮台镇的生态风险度高,西杨乡、东岗镇和驼山乡生态风险由极高降为高或中,生态安全度有所提高。研究表明,人口和社会经济发展是影响瓦房店市景观格局变化的主要因素,该区域未来海岸带要实现可持续开发必须要进行科学的规划。     

Improvement of photorefractive properties in Hf:Fe:LiNbO3 crystals with various [Li]/[Nb] ratios

Photorefractive properties of Hf:Fe:LiNbO₃ crystals with various [Li]/[Nb] ratios have been investigated at 488 nm wavelength based on the two-wave coupling experiment. High diffraction efficiency and large recording sensitivity are observed and explained. The decrease in Li vacancies is suggested to be the main contributor to the increase in the photoconductivity and subsequently to the induction of the improvement of recording sensitivity. The saturation diffraction efficiency is measured up to 80.2%, and simultaneously the recording sensitivity of 0.91 cm/J is achieved to in the Hf:Fe:LiNbO₃ crystal grown from the melt with the [Li]/[Nb] ratio of 1.20, which is significantly enhanced as compared with those of the Hf:Fe:LiNbO₃ crystal with the [Li]/[Nb] ratio of 0.94 in melt under the same experimental conditions. Experimental results definitely show that increasing the [Li]/[Nb] ratio in crystal is an effective method for Hf:Fe:LiNbO₃ crystal to improve its photorefractive properties.     

Effects of different types of mechanical disturbances on a charophyte dominated macrophyte community

Charophytes are unique and endangered macroalgae. Mechanical stress is known to damage charophyte communities, however, virtually nothing is known how such disturbance affect seasonal succession and recovery of charophyte communities. We examined the response of a shallow water charophyte community to different types and timing of disturbances by conducting seasonal in situ field experiment in a brackish water ecosystem. The disturbances associated with mechanical removal of vegetation or sediment had the largest impact on the charophyte community. Disturbances that only partly damaged the plants had minor effects and communities were characterized by fast recovery. The timing of disturbance had significant effects on the charophyte community with stronger effects when disturbed at the early stage compared to mid-stage of seasonal succession.     

Guiding ecological principles for marine spatial planning

The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits.     

内蒙古区域数值预报对探空和地面观测资料的敏感性试验研究

基于内蒙古睿图预报系统的低分辨率版本和WRFDA-FSO诊断工具,评估2021年7月现有探空和地面观测对内蒙古睿图预报系统预报的影响。该方法计算代价相对低廉,并允许根据观测变量、观测类型、气压层次、地理区域等观测的子集对观测影响进行划分。代价函数为以干总能量为度量的背景场和分析场的预报误差之间的差异。结果表明:观测影响的总体总和为负,观测对预报起正贡献作用。对12 h预报误差减小贡献最大的观测来自探空观测的动力变量(U、V风分量)。而单时次单位数量平均观测影响,探空观测的贡献约为地面观测的1/2。探空观测对12 h预报误差减小从近地面层至模式层顶均保持正贡献作用,并在对流层中低层和对流层高空急流层存在两个极大值区域;地面观测在850 hPa以下低层正贡献占比明显。探空观测在被同化系统同化时均总体具有有利的影响,也反映出探空观测数据稳定、质量较高的特征;地面观测对12 h预报误差减小起正贡献作用次数最多的区域在河套地区尤为显著。同时,探讨了需进一步提高地面观测资料同化率的问题。     

长江源区生态及灾害地质调查与防治对策

简述了长江源区自然地理和生态地质环境特征,分析了环境恶化的主要原因及防治对策。     

时间加密探空观测对分析和预报质量的敏感性研究

探空观测是气象资料同化中最基本的常规观测资料,对同化分析和预报的有效改善具有重要作用。由于现有探空观测站的空间分辨率较低,分布不均匀,且每日仅有两次观测,数量偏少,限制了其分析场对中小尺度大气状态的准确再现能力。自我国L波段雷达-数字探空仪更新换代以来,探空观测具备了获取每日4次、垂直分辨为秒级和分钟级的大气廓线资料。本文利用WRF中尺度数值模式,通过06时（世界时,下同）加密探空资料和12时常规探空资料的有效同化,研究分析了时间加密探空观测资料对同化分析和预报质量的敏感性影响。结果表明：同化06时的时间加密探空资料的午后暴雨预报质量优于12时常规探空观测。具体而言,同化06时的时间加密探空资料预报的大雨和暴雨的预报技巧高于12时常规探空资料;位势高度、温度和风场等预报场的均方根误差在高层的改进效果更加明显;06时的时间加密探空资料的同化对高层的高空急流和低层的水汽通量散度的预报质量贡献更大。批量试验进一步证实了有效同化时间加密探空资料对分析和数值预报效果改进的积极意义。     

Elman神经网络在低渗储层敏感性预测中的应用

油气储层敏感性是制约低渗储层有效开发的重要因素之一,但在勘探开发早期储层敏感性预测及分布规律的研究受到资料不足的限制.从实验敏感性分析结果入手,对Elman神经网络预测储层敏感性的过程及方法进行了系统的分析,并提出了通过设置虚拟井来预测储层敏感性平面分布的方法.结果表明:①影响低渗储层敏感性的主要因素有蒙皂石、伊利石、高岭石、绿泥石、伊-蒙混层、石英、长石的体积分数,孔隙度和渗透率;②Elman神经网络能够很好地预测低渗储层的敏感性,预测结果与实测结果绝对误差的平均值均低于0.04,水敏性样品的预测结果与实测结果绝对误差的平均值为0.001;③通过设置虚拟井位,能够很好地预测储层敏感性的平面分布规律.