Causes and control countermeasures of eutrophication in Chaohu lake,China

1 IN T R O D U C T IO NC haohu Lake,located in the centralA nhuiProvince ofC hina, has m ultiple functions of flood control, w atersupply,irrigation,transportation,fishery and tourism .Itis fam ous for its beautifullandscape and historic sites.For thousan…     

基于贝叶斯方法的湖泊富营养化评价

对湖泊富营养化状态的有效评价是对湖泊进行有效管理的重要手段之一。针对富营养化评价中的不确定性,拟采用概率方法——贝叶斯方法对富营养化状态进行评价。以水利部水利水电规划设计总院提出的《地表水富营养化控制标准》为评价标准,选取Chla、TP、TN、CODMn、SD5个指标,对我国19个湖泊应用贝叶斯方法进行富营养化评价,并应用两个实例对该方法在富营养化评价中的有效性进行了验证。结果表明,贝叶斯方法应用于湖泊富营养化评价具有简单、实用的特点。     

Evaluating lake eutrophication with enhanced thematic mapper data in Wuhan

1 INTRODUCTION Increasing eutrophication of lakes in recent years as a result of human impact has become a se- rious environmental problem in China. Many lakes in the Jianghan Plain, South China, for example, especially near major cities, have been eutrop…     

Response of Cultural Lake Eutrophication to Hemp-retting in Quidenham Mere of England in Post-Medieval

To study the influence of human activity on natural lake, chironomid fauna change in the 700–560cm lake sediment in Quidenham Mere of England associated with chironomid inferred TP presented that the lake experienced a whole eutrophication process due to human hemp-retting in Post-Medieval based on the history record and pollen analysis, which was confirmed by mollusc and ostracod analysis. However, the response of chironomid and mollusc to retting was the strongest with ostracod a little behind. It proved that cultural eutrophication existed in history and could be recovered by itself despite of some long-term unachievable destroy. And it was most important for external nutrient to be cut off during lake restoration even in ancient times.     

Application of an integrated methodology for eutrophication assessment: a case study in the Bohai Sea

An integrated methodology for eutrophication assessment,which integrates both water quality indicators(causative factors) and ecological response indicators(effect factors),is described.It is then applied to rank the eutrophication status of the years 2007 and 2008 in the southwest Bohai Sea.The assessment model identified that north Bohai Bay and west Laizhou Bay were the two areas with the most serious eutrophication problems in the southwest Bohai Sea.In addition,compared to that in the west Laizhou Bay,the eutrophication conditions in the north Bohai Bay was more serious in both years.Eutrophication problems such as harmful algal blooms(HABs) and low dissolved oxygen(DO) events in north Bohai Bay were frequent.The integrated method outmatched the currently used Chinese nutrient index method by definitely identifying areas with the most serious eutrophication problems,while the nutrient index method gave ambiguous results between the two years.Inclusion of both causative factors and effect factors,combining concentration,spatial coverage and frequency of indicators,as well as use of multi-season monitoring datasets in the methodology result in a more accurate,representative and useful assessment.     

The effects of co-cultivation of pearl mussels and fishes on water pollution control in middle or small sized water

Our field experiments showed that the cultivation of pearl mussels formed a new biocoene composed of filamentous algae, protozoa, porifera and coelenterate. It effectively reduced nitrogen, phosphorus,chemical oxygen demand and biochemical oxygen demand in the water by 67.3%, 73.2%, 38.1% and 15.5%,respectively, during May to September 1998 when the water eutrophication was developing. This could control water eutrophication and produce pearls, shellfish meat and shells. This is an economical and effective way to control water eutrophication by using the ultra strong filtering capability of freshwater pearl mussels.     

Study on fluxes of CH4 emission from paddy fields in Changchun area

Little has been done in measurement and research of the flux of CH₄ emission from paddy fields in Changchun area, Jilin Province, China before 1994. So the purpose of the study is to offer available regional data of CH₄ emission flux and to discuss the factors which affect CH₄ emission from paddy fields. Experimental paddy fields are chosen using TM pictures respectively in Xinlicheng (43°49′N, 125°20′E) of the Yitong River’s and in Wanchang (43°44′10″N, 125°53′11″E) of the Yinma River’s alluvial plain. The fluxes of CH₄ emission from paddy fields are measured by the method of static chamber in Changchun area in 3 consecutive years. The research results show that the peak of CH₄ emission from paddy fields occurs during the booting stage. The mean fluxes of CH₄ emission are 7.056 mg/m(² · h) and 0.489 mg/(m² · h) in the paddy fields of flood and discontinuous irrigation respectively. The contrastive study holds that climate condition, the way of water management and fertilizer variation have significant influence on fluxes of CH₄ emission from paddy fields. The difference of climatic conditions causes the interannual change of the flux of CH₄ emission from paddy fields. In general, the flux of CH₄ emission from paddy fields of flood irrigation is greater than that from paddy fields of discontinuous irrigation. To change the way of water management perhaps in an available way to reduce CH₄ emission flux from paddy fields. Foundation item: Under the auspices of Jilin Commttee of Science and Technology (grant 963416 - 1), and Changchun Jingyuetan Remote Sensing Test Site of the Chinese Academy of Sciences (grant 9504). Biography: YAN Min-hua (1964 -), female, a native of Liaoning Province, master, associate professor. Her research interests include climate change, greenhouse gases and wetland climate.     

Study on anti-noise scheme for detecting PPM information in shallow water channels

INTRODUCTIONThemultipatheffect,signalfluctuation (Huangetal.,1 998a,b) ,andnoiselevelinshallowwaterchannelshinderdetectionofpulsepositionmodulation (PPM)information .Thispaperdis cussesmarinenoisehindrancetoprecisedetectionofPPMinformation ,andpresentssomefeasiblecountermeasurestosuppressnoiseinterferenceeffectively .Itiswellknowneffectivedetectionofinformationbyareceivingsystemiscruciallydependentonthesignal to noiseratio(SNR) .Asrelativelyhighnoiselevelexistsinshallowwateracousticch…     

单道地震资料处理关键技术研究及在长岛海域的应用

单道地震作为海上地震勘探测量方式的一种,采用自激自收的测量方式,具有施工效率高、资料处理解释快速的优点,广泛应用于海上地质调查。本文对单道地震资料处理方法进行了研究,提出了一整套处理流程,重点是采用SRME算法对多次波进行压制,提高数据信噪比。将上述算法应用于长岛海域单道地震资料处理,取得了良好的效果。     

云母石英片岩蠕变模型参数选择研究

根据三轴蠕变试验曲线的特点,建立了云母石英片岩七元件线性黏弹塑性蠕变模型,采用最小二乘法对蠕变柔量时间曲线和应变时间蠕变曲线进行拟合确定蠕变模型参数,讨论了确定蠕变模型参数的影响因素及参数的合理性与可用性。结果表明:由于受到分级加载次数、初次加载应力值和加载时间的影响,两种曲线拟合确定的参数各不相同;云母石英片岩蠕变模型的非线性较明显;蠕变柔量时间曲线拟合确定的参数不予采用,应变时间蠕变曲线拟合确定的参数在各级应力水平下变化规律不明显;采用某种单一方法确定蠕变模型参数不够全面,建议采用综合辨识法,这样才能保证岩土工程中蠕变数值分析结果的正确合理性以及施工设计的安全可靠性。     

临沂市地质灾害防治工作初探

临沂市地处郯庐大断裂带中段,地质构造运动强烈,灾害易发区占全市国土面积的52.5%,地质灾害问题已成为制约全市经济社会可持续发展和影响社会稳定的重要因素之一。近年来临沂市坚持以人为本、预防为主、防治结合、综合治理,连续6年保持地质灾害零伤亡,被国土资源部表彰为全国地质灾害防治工作先进单位。     

临沂市土地可持续利用评价研究

从资源合理性、经济可行性、社会可接受性3个方面,建立了土地可持续利用综合评价指标体系。采用层次分析法确定了指标权重,应用模糊数学中的隶属函数对指标体系中的各项指标进行无量纲化处理,然后用加权法求得临沂市1995--2004年的土地可持续利用水平,用协调度模型求得临沂市土地可持续利用的协调度,运用障碍度模型,分析了各项指标的障碍度。     

论黄河泥沙的综合开发利用

黄河泥沙资源丰富。如何处理黄河泥沙,历来是黄河治理开发的大事。该文结合黄河下游山东、河南两省的实际情况,在论证综合开发利用黄河泥沙的可能性、技术支撑、市场需求、法制环境等基础上,提出了淤改涝洼地、制造墙体材料、复垦采煤塌陷区等综合利用黄河泥沙的建议。     

Study on model for remote sensing estimation of maize yield

Through analysis of perpendicular vegetation index (PVI) from combination of visible and near-infrared spectrums reflecting the feature of crop reflectance, we come to the conclusion that the index can better indicate crop instantaneous photosynthesis whereas people generally regard it as the representation of crop leaf area index (LAI). Exploration of crop photosynthesis within a day and its period of duration leads to production of photosynthetic vegetation index (PST) that can reflect the whole crop accumulated photosynthesis, which means the total biomass produced by crop, moreover the method simulating PST is put forward by employment of multi-temporal spectrum parameters. On the basis of the achievements mentioned above, a new comprehensive model for remote sensing estimation of maize yield is established, which can comprehensively show major physiological actions of maize and the course of its yield formation, organically integrate various effective ways of crop yield estimation. It lays a solid foundation for carrying out remote sensing estimation of maize yield on a large scale.     

临沂市土地可持续利用评价研究

从资源合理性、经济可行性、社会可接受性3个方面,建立了土地可持续利用综合评价指标体系。采用层次分析法确定了指标权重,应用模糊数学中的隶属函数对指标体系中的各项指标进行无量纲化处理,然后用加权法求得临沂市1995—2004年的土地可持续利用水平,用协调度模型求得临沂市土地可持续利用的协调度,运用障碍度模型,分析了各项指标的障碍度。     

Study on model for remote sensing estimation of maize yield

ＳＴＵＤＹＯＮＭＯＤＥＬＦＯＲＲＥＭＯＴＥＳＥＮＳＩＮＧＥＳＴＩＭＡＴＩＯＮＯＦＭＡＩＺＥＹＩＥＬＤＬｉｕＺｈａｏｌｉ（刘兆礼）ＨｕａｎｇＴｉｅｑｉｎｇ（黄铁青）ＷａｎＥｎｐｕ（万恩璞）ＺｈａｎｇＹａｎｇｚｈｅｎ（张养贞）ＣｈａｎｇｃｈｕｎＩｎｓｔｉ...     

区域生态环境综合信息图谱的分类与案例分析——以福建省为例

生态环境图谱类型的划分是自然资源合理开发利用和治理及地学信息图谱研究的基础。该文采用系统分析的思路,在总结对比分析前人对土地利用/土地覆被、植被、地貌、景观以及生态环境等的分类研究的基础上,依据地学信息图谱的方法论,借助遥感和地理信息系统等技术,构建生态环境综合信息图谱分类的系统,并以福建省为例,提出福建省生态环境图谱的分类系统。     

基于综合评价的日照市农用地整理时序研究

通过探讨农用地整理的时序,为规范土地整治管理提供技术支撑。运用综合评价法、实证分析法,选取自然经济社会条件、耕地利用现状和农用地整理3个因素、6个评价因子,构建农用地整理评价指标体系。以山东省日照市为例,进行实证分析,确定49个乡镇农用地整理时序。得出通过综合评价确定农用地整理时序,能够使农用地整理管理更加科学化和规范化。     

山东省枣庄市地质灾害现状研究及防治建议

在搜集、分析2020年以往资料的基础上,对枣庄市已知地质灾害点和新增地质灾害点进行核查、调查,最终保留地质灾害点80处。其中崩塌、滑坡和岩溶塌陷为小型规模,采空塌陷以大、中型规模为主。对地质灾害核查数据进行综合研究,总结分析枣庄市地质灾害分布特征和发育规律,对各区进行地质灾害易发程度综合分区评价,划分为高易发区、中易发区、低易发区、不易发区4个级别;根据地质灾害及隐患的发育特征,易发性、稳定性及危险程度,结合当地经济与社会发展规划等因素,进行综合分析,把枣庄市地质灾害防治分为重点防治区、次重点防治区和一般防治区。提出合理的防治规划建议和防治措施,为枣庄市地质灾害防治工作提供基础依据。     

虚拟地理环境知识工程初探

地理知识在虚拟地理环境（Virtual Geographic Environments,VGE）的科研与应用中发挥着极为重要的作用。现有地理知识工程研究整体处于初步探索阶段,且尚未在虚拟地理环境中展开。作为新一代GIS研究的科学方法和技术,虚拟地理环境具有典型的多领域、多协同、多交互、多模型及多感知的特点,但还亟需系统深入地了解VGE地理知识工程的特点、机理及关键技术。本文首先综述了国内外现有知识工程及地理知识工程研究现状,进而提出了VGE地理知识及VGE知识工程的概念和定义。在此基础上,本文分析了VGE地理知识有别于通用知识的特点,并提出了VGE地理知识的分类。最后,针对VGE地理知识工程的构建阐述了需解决的关键问题。本文基于VGE知识工程的初步探索,尝试为智能虚拟地理环境系统的构建提供理论基础,以促进虚拟地理环境中地理知识的快速转换和融合,为解决地理科学“数据丰富但知识贫乏”的问题提供一个可行的研究方向。