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1.
基于实码遗传算法的湖泊水质模型参数优化   总被引:1,自引:0,他引:1       下载免费PDF全文
郭静  陈求稳  张晓晴  李伟峰 《生态学报》2012,32(24):7940-7947
参数的合理取值决定着模型的模拟效果,因此确定研究区域的模型结构后,需要对模型的参数进行优化.湖泊水质模型(Simulation by means of an Analytical Lake Model,SALMO)利用常微分方程描述湖泊的营养物质循环和食物链动态,考虑了多个生态过程,包含104个参数.由于参数较多,不适宜采用传统参数优化方法进行优化.利用太湖梅梁湾2005年数据,采用实码遗传算法优化了SALMO模型中相对敏感的参数,运用优化后的模型,模拟了梅梁湾2006年的水质.对比分析参数优化前后模型的效果表明遗传算法能高效地对SALMO进行参数优化,优化后的模拟精度得到了显著提高,能更好地模拟梅梁湾的水质变化.  相似文献   

2.
风场对太湖叶绿素a空间分布的影响   总被引:3,自引:0,他引:3  
叶绿素a的浓度是水环境评价的重要参数。根据2005—2009年太湖全湖32个采样点的20次太湖采样数据,结合气象要素资料模拟的太湖风场,探求了风场对太湖叶绿素a空间分布的影响。结果表明:叶绿素a浓度的高值中心位于太湖西北侧、竺山湾以及梅梁湾流域,而太湖东南部的叶绿素a浓度较低;全太湖全年以东南风为主,南部风速较大,北部风速较弱;风场对叶绿素a的输移作用明显,在风场作用下,叶绿素向太湖西北部和北部输移,造成了该地区太湖流域叶绿素浓度普遍偏高。  相似文献   

3.
滇池外海蓝藻水华爆发反演及规律探讨   总被引:4,自引:0,他引:4  
气象条件和营养盐浓度一直被认为是导致蓝藻水华爆发的两个重要因素。通过滇池外海Chla浓度时空分异性分析,得出晖湾中测点最易爆发蓝藻水华且爆发时间集中在每年6—9月。同时,采用基于缺失数据多重插补的EMB算法将气象条件和蓝藻水华爆发的不完全数据集进行反演,建立了滇池外海2004—2008年4—10月完整的气象、营养盐及蓝藻爆发的基础数据集,解决了表观蓝藻水华爆发研究中观测数据缺失的问题。据此,探讨了滇池外海晖湾中测点Chla、TN和TP与蓝藻水华爆发关系,进而提出了控制滇池外海蓝藻水华的一种新思路。  相似文献   

4.
Feng YJ  Liu Y  Han Z 《应用生态学报》2011,22(4):957-963
利用元胞自动机(cellular automata,CA)模拟土地利用情景,有助于理解其变化机理,并为土地资源持续利用提供空间决策支持.本文基于生物进化过程的遗传算法(genetic algo-rithm,GA)将CA参数编码成为染色体,在模拟结果与真实结果差异值的引导下,通过选择、杂交和变异算子使最优的染色体得以遗传和保留,从而建立智能优化的元胞自动机模型.以浙江省嘉兴市1992-2008年土地利用变化为例,分别利用6%(66个·km-2)和3%(33个·km-2)两种样本方案构建遗传CA模型进行土地利用变化模拟,并通过混淆矩阵、Kappa系数和景观指数对模拟结果进行评估.结果表明:遗传CA模拟结果能在数量、位置和景观格局上以超过80%的水平接近真实分类,且大样本量构建的遗传CA的模拟精度更高;2008年的模拟精度和景观综合指数低于2001年,表明遗传CA的模拟精度和景观综合指数随模拟时间而衰减.  相似文献   

5.
环太湖复合型生态网络构建   总被引:13,自引:6,他引:7       下载免费PDF全文
生态网络构建的定量化研究已在生态规划中发挥了重要作用,但复合型生态网络构建却仍旧停留在理论探索与创新阶段。以环太湖地区为例,基于RS和GIS软件平台,采用最短路径分析方法模拟研究区潜在的生态廊道;然后叠加景观、游憩图谱网络,进行无标度网络的构建和检测,构建空间效能好的环太湖复合型生态网络图谱,并据此有针对性地提出复合型生态网络结构和框架优化的建议。研究结果表明,环太湖区域的生态网络和景观、游憩网络可以通过图谱分析和无标度网络检测进行整合,构建出空间效能好的复合型生态网络模型,从而指导环湖生态、景观、游憩资源的耦合发展与廊道建设;通过对不同分区的图谱形态和指标分析,具有小世界网络特征的太湖北部的苏州段和无锡段应以保护和连接为重点,南部的湖州段无标度网络特征明显,成长潜力较好,需要进行高质量的规划保护和开发。  相似文献   

6.
利用2009~2010年周年观测数据,结合江苏太湖湖泊生态系统研究站15年监测数据,分析了太湖梅梁湾湖岸带浮游植物群落演替及其与蓝藻水华形成的关系。50次周监测结果表明:蓝藻门(Cyanophyta)、绿藻门(Chlorophyta)、硅藻门(Bacillariophyta)分别占浮游植物总生物量的60%、16%和22%。冬春季绿藻、硅藻为主要优势种,夏秋季蓝藻门的微囊藻占绝对优势。4月下旬~6月初,平均温度低于20°C,蓝藻没有大规模生长,硅藻门、绿藻门生物量急剧降低,总生物量小于1mg.L-1;随后温度超过25°C,蓝藻迅速增长并很快成为绝对优势,蓝藻增加滞后于绿藻、硅藻的减少。在营养盐充足、物理因素合适的条件下,浮游植物群落结构自然演替是蓝藻水华形成的主要原因之一。  相似文献   

7.
水华蓝藻何以肆虐?   总被引:2,自引:0,他引:2  
曾几何时,秀美的太湖湖光山色,是多少文人墨客向往的天堂。如今,太湖严重的蓝藻水华却成为环太湖地区,包括其他国人的忧患所在。今年5月,太湖蓝藻大规模暴  相似文献   

8.
冯永玖  陈新军  杨晓明  高峰 《生态学报》2014,34(15):4333-4346
鱼类栖息地适宜性指数模型(HSI)基于鱼类分布与海洋环境之间存在的非线性关系而构建。然而,海洋环境因子之间存在着传统方法无法消除的相关性,导致获取的HSI参数较难准确表达环境因子与渔场之间的复杂关系。基于遗传算法(GA),自动消除海洋环境因子之间的相关性,构建了一种通用的鱼类HSI建模与智能优化框架(GeneHSI)。GeneHSI框架的核心是HSI建模空间向遗传算法空间的映射以及GA适应度函数的构建。该函数构建的思想是HSI预测的渔场概率与商业捕捞获取的渔场概率之间的累计误差值达到最小化。GeneHSI由待解问题构建、GA初始化和GA优化策略3部分组成。利用随机生成的标准化海洋环境数据与渔场概率数据,验证了GeneHSI模型框架的有效性。研究表明,GeneHSI能够有效优化HSI的建模并能自动获取HSI参数。不同限制条件下,遗传算法获取的HSI具有较大的差异,其中一般优化策略下获取的HSI参数最差;不等式、等式和上下界条件下,GeneHSI优化过程显著地更加合理,因此获取的HSI参数也更准确。此外,100、1000、5000和10000样本量下的优化建模表明,GeneHSI具有处理海量样本数据的能力。  相似文献   

9.
太湖湖岸带浮游植物初级生产力特征及影响因素   总被引:1,自引:0,他引:1       下载免费PDF全文
蔡琳琳  朱广伟  李向阳 《生态学报》2013,33(22):7250-7258
利用高频溶解氧监测,估算了太湖梅梁湾湖岸带浮游植物初级生产力的高频变化特征。结合同步气象监测及浮游植物、浮游动物和营养盐的周年逐周观测数据,分析了气象和环境条件对富营养化湖泊浮游植物初级生产力的影响。结果发现,高频溶解氧监测估算的初级生产力变化与浮游藻类生物量的变化一致,能够反映出浮游植物生产力的昼夜变化、季节变化等规律。统计分析表明,气温对太湖这一富营养化湖泊初级生产力影响很大;氮的供给与浮游动物的选择性牧食也是影响浮游植物初级生产力的重要因素。湖岸带的水华堆积过程对初级生产力影响巨大,气象、水文过程又加剧了蓝藻水华初级生产力的变化幅度,反映出富营养化湖泊初级生产力可能存在极大的时空不均一性。研究表明,溶解氧高频监测法估算初级生产力能够捕捉到湖泊初级生产力的快速变化过程,可以用于富营养化湖泊初级生产力监测、蓝藻水华灾害预警中。  相似文献   

10.
由于参数较少且具有明确的物理学意义,基于水热平衡理论的Budyko假设常用于定量分析以及评价气候变化和植被变化对实际蒸散发的影响,对研究流域水量平衡和能量分配具有重要意义。依据位于我国北方密云水库上游的潮河流域1961—2015年的水文气象数据,选取了4种基于Budyko假设的模型来研究潮河流域水热耦合平衡关系,确定了该流域最适用模型以及模型参数最优值,并且采用情景设置法分析了流域实际蒸散发对气候以及植被变化的响应。结果表明:(1)与经典Budyko模型相比,采用流域下垫面参数修正的Budyko模型计算实际蒸散发的精度更高。其中,傅抱璞模型精度最高,决定系数、相对误差、纳什效率系数和均方根误差分别为0.85、4.30%、0.82和27.66 mm;(2)对傅抱璞模型下垫面参数ω进行优化,确定适用于潮河流域的模型参数取值为2.54,优化后的傅抱璞模型能够更好地反映流域实际蒸散发的变化特征;(3)情景模拟表明,气候变化和植被变化的共同作用导致潮河流域实际蒸散发的上升。其中,气候变化是引起流域蒸散发变化的主要驱动因素。  相似文献   

11.
Impacts of the Yangtze River water transfer on the restoration of Lake Taihu   总被引:12,自引:0,他引:12  
In order to improve the water quality and to abate the jeopardy of water bloom in Lake Taihu, China, two experimental water transfers from the Yangtze River to Lake Taihu were conducted in winter–spring 2002 and in summer–autumn 2003. In this study, an ecological model (EcoTaihu) was introduced to assess their environmental effects. First, the model was re-calibrated and reverified for the periods of the water transfer, then numerical calculations with and without the water transfer were carried out. The percentage of the area where water quality was improved by the water transfer was calculated in seven sub-zones of the lake. The results show that the experimental water transfers in both of the periods have notable positive effects on debasing the concentration of phytoplankton, total nitrogen and dissolved oxygen in some sub-areas. The positive effects fluctuated with the duration of the water transfer, and were different for different water quality parameters and in different sub-zones. Among the five water quality parameters considered, chlorophyll a achieved the most significant improvement. There are no notable positive effects on the total phosphorus in any sub-zones. Meiliang Bay, Gonghu Bay and Northwest Zone had more positive effects than the east epigeal zone and Dongtaihu Bay. As the water transfer results in net input of nitrogen and phosphorus to Lake Taihu, it can only be used as an emergency measure to abate the jeopardy resulting from water bloom. Otherwise, the water transfer would increase the risk of eutrophication in Lake Taihu if the concentration of phosphorus and nitrogen in the influent water was not cut down to a reasonable level.  相似文献   

12.
王锋文  钟萍  刘正文 《生态科学》2011,30(3):340-345
采集太湖不同生态类型湖区(草型湖区胥口湾;风浪大、水华较少的湖心区和水华较严重的梅梁湾)沉积物柱状样,研究沉积物理化性质以及孔隙水无机氮浓度垂直变化特征。结果显示,各点含水率、有机质、总氮均随深度增加而降低,而梅梁湾含量最高,湖心区最低。沉积物溶解氧随深度增加而降低,胥口湾最高,梅梁湾最低。孔隙水NH4+-N随深度增加而增大,NO3--N、NO2--N均随随深度增加而减小。比较表层0-5cm沉积物孔隙水和上覆水无机氮浓度,发现各湖区NO3--N和NO2--N释放风险小,胥口湾(草型湖区)和梅梁湾(藻型湖区)NH4+-N释放风险较大,湖心区较小。  相似文献   

13.
Lake eutrophication: Control countermeasures and recycling exploitation   总被引:6,自引:0,他引:6  
Boqiang Qin   《Ecological Engineering》2009,35(11):1569-1573
Eutrophication is a world-wide environmental issue. Lake Taihu is a typical large, shallow, eutrophic lake located in delta of River Changjiang (Yangtze River). A large-scale ecological engineering experiment targeted at water quality improvement was implemented in Meiliang Bay, Lake Taihu. In this special issue, there are six papers related to water purification and algal bloom control techniques applied in this experiment. Four papers address the validity and efficiency of water quality improvement of this ecological engineering and one paper presents a similar but small-size ecological engineering. The others focus on macrophyte restoration, aquatic plant management and recycling exploitation. The editorial paper highlights the main results and conclusions from these papers.  相似文献   

14.
太湖水华程度及其生态环境因子的时空分布特征   总被引:2,自引:0,他引:2  
张艳会  李伟峰  陈求稳 《生态学报》2016,36(14):4337-4345
湖泊水华是全世界面临的严重生态环境问题之一,对人类和生态系统健康都有重大影响。由于湖泊水华受流域面源、点源污染、气候、水文因子以及湖泊生态系统自身特征等众多因素影响,水华是否爆发、其严重程度及时空分布特征呈现明显的复杂性。以我国太湖为研究区域,基于近年的水华及水环境的监测数据,用自组织特征映射神经网络对太湖不同监测点的水华程度进行了自动聚类分析。结果表明,太湖水华程度呈现为明显的无水华、轻度、中度和重度水华4类。不同程度水华的叶绿素a、水温、COD_(Mn)、营养盐、浮游植物生物量以及藻种(蓝藻、绿藻、硅藻)结构的时空差异显著,不同变量间的关系复杂,有助于深入认识太湖近年水华发生的时空变异特性。  相似文献   

15.
Due to the difficulty of quantifying the temporal and spatial variations of the sewage sources of Taihu Lake, this paper collected water samples from Gonghu Bay and Meiliang Bay, in the northeast of Taihu Lake and from the inflow river of Wangyu River from January to December in 2012 and applied stable isotope techniques to trace the sources of the nitrogen pollutants. At the same time, a two-end-member mixing model of isotopes was used to determine the sources of domestic sewage. According to the results of nitrogen isotope values in the sampling points, the annual proportion of the sewage sources of the Meiliang Bay, Gonghu Bay and Wangyu River is 17.2%, 15.3% and 19.7%, respectively. More than 80% of the nitrogen pollution sources are from non-domestic sewage, which indicates that domestic sewage is not the primary source of nitrogen pollution in Taihu Lake. In addition, these three regions have demonstrated higher ratios of sewage sources during the winter season than during other seasons. Therefore, domestic sewage that flows into Taihu Lake during the winter season should be strictly limited. In the meantime, it is necessary to strengthen the treatment of nitrogen sources other than domestic sewage sources.  相似文献   

16.
An ecological project for water purification was conducted in Meiliang Bay, Lake Taihu, which supplies one-third of the drinking water for Wuxi City, China. Sediment dredging was employed. The floating-leaf and floating macrophytes were planted, combined with wave-attenuating, algal bloom blocking to improve the water quality. At the same time, large amounts of fish net were placed in the experimental zone, to which massive periphytes adhere. To evaluate the effectiveness of remediation, many studies were based on chemical analysis or acute toxicity test. In this study, chronic toxicities before and after the ecological project in Meiliang Bay, Lake Taihu, China, were evaluated based on a battery of in vitro bioassays, including EROD bioassay, recombined yeast assay, as well as umu test for detection of Ah-receptor (AhR) agonists, estrogenic chemicals and genotoxic chemicals, respectively. Before remediation, AhR effect, estrogenic effect and indirect genotoxicity were all detected in sediments of Meiliang Bay, Taihu Lake. After amelioration, levels of AhR agonists decreased by 42.3–80.7%, estrogenic chemicals decreased by 71.6–93.9% and indirect genotoxic chemicals decreased by 23.2–75.0%. Results showed that the ecological project effectively removed the chronic toxicants from the sediments.  相似文献   

17.
太湖春季水体固有光学特性及其对遥感反射率变化的影响   总被引:4,自引:0,他引:4  
吸收特性和后向散射特性是水体重要的光学特性,同时也是建立生物光学模型的基本参数。利用2009年4月太湖春季实测数据,结合生物光学模型推导了太湖春季水体颗粒物后向散射系数,在此基础上分析了太湖春季水体的吸收特性和后向散射特性,并利用经验正交分解方法对遥感反射率变化的影响因子进行了分析。结果表明:(1)非色素颗粒物是影响太湖春季水体吸收特性的主导因子,色素颗粒物和CDOM对总吸收(不包含纯水)的贡献相对较小,且色素颗粒物在梅梁湾湖区的包裹效应明显大于其他湖区。(2)颗粒物后向散射系数与总悬浮物和无机悬浮物具有很强的相关性(相关系数均在0.88以上),与有机悬浮物的相关性相对较弱(相关系数均在0.73以下),且水体中多次散射对水面总辐亮度有较大的贡献,平均贡献率高达93.46%。(3)利用经验正交分解方法将遥感反射率变化光谱分解成3个正交因子,3个正交因子总共解释了约99%的遥感反射率变化信息,其中,第一正交因子解释了93%的变化信息,第二和第三正交因子分别解释了5%和1%的变化信息。通过对各正交因子与水体不同组分的吸收和后向散射系数进行相关性分析得出,颗粒物的后向散射对水面反射光谱的形成具有非常重要的影响,太湖春季水体遥感反射率的变化主要取决于无机颗粒物的吸收和后向散射,有机颗粒物对遥感反射率的变化影响较小。  相似文献   

18.
Using a case study of Lake Chaohu, the fifth largest lake in China, we constructed a cusp model for water bloom prediction that used TP (total phosphorus), T (temperature), Chla (chlorophyll-a), and DO (dissolved oxygen). These four parameters were assumed to be the most important factors in eutrophication and water bloom of the lake. The model was found to be accurate, because its relative error was around 10%. What is more convincing, according to the catastrophe discriminant of the cusp model, it could be judged that a discontinuous jump of the aquatic ecosystem occurred in July 2004, in Lake Chaohu. This conclusion is consistent with the fact that water blooms arose in August 2004. The cusp model also showed satisfactory precision when applied to forecast the eutrophication trend and prediction of water bloom in Lake Chaohu in 2005. The case study found that water bloom brought on by eutrophication can be fit and predicted by a catastrophe model. We suggest that catastrophe models would be a constructive approach to forecast and judge the outbreak of water bloom in lakes. In addition, by constructing and studying such catastrophe models, lake managers would be able to simulate the effects of different protection and mitigation projects and enrich the scientific basis for the optimization of these projects as well.  相似文献   

19.
太湖蓝藻死亡腐烂产物对狐尾藻和水质的影响   总被引:8,自引:0,他引:8  
为揭示富营养化造成淡水生态系统中沉水植物消亡的机制,本文就太湖蓝藻大规模死亡腐烂后的产物对水体水质以及沉水植物造成的影响进行了研究。本文以沉水植物穗花狐尾藻为研究对象,测定了水质参数(pH值,浊度(NTU),温度,溶解氧(DO),电导率(Ec),盐度,磷酸根(PO43-))以及狐尾藻Fv/Fm指标。将采自太湖梅梁湾的蓝藻水华,降解一个星期左右。随后在处理组中加入该蓝藻降解物,对照组中不加入。结果表明,加入蓝藻死亡腐解液后,水体的溶解氧、pH值均比对照组显著降低,浊度则显著升高。对照组中穗花狐尾藻生长良好,其Fv/Fm约为0.8,而经蓝藻腐烂液处理的实验组,穗花狐尾藻在两天之内便接近死亡状态,其Fv/Fm值降至0.3左右。以上结果表明蓝藻死亡腐烂后形成的腐解液确实能在很短时间内给沉水植被带来灭顶之灾。而在短时间内并不能形成大量附着生物,故本实验可排除其对水生植物的影响。本文证实了蓝藻死亡腐烂后的降解液极有可能是导致沉水植物消亡的主要原因。至于是由于蓝藻腐解液引起的哪种因素起主导作用,还有待进一步研究。  相似文献   

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