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991.
利用吉林省业务运行的中尺度数值模式WRF3.3.1,分析了2016年4月12日吉林省一次春季降水过程的人工增雨潜力,选取比湿、上升气流、K指数、冰面过饱和度、云水厚度共5种与人工增雨潜力密切相关的指标,作为吉林省春季人工增雨潜力判别的因子。结果表明:吉林省春季850 hPa比湿和K指数与降水量存在相关关系,比湿小于2.9 g·kg-1几乎不产生降水,产生2 mm以上的降水比湿几乎均大于4.5 g·kg-1,K指数大于22℃。将850 hPa比湿大于4.5 g·kg-1、K指数大于22℃、积分云水含量大于0.2 mm、高层冰面过饱和度大于0和低层垂直速度大于0.4 m·s-1作为强增雨潜力区的指标,并利用春季其他个例对该指标进行检验,发现该指标基本能够表征云内的动力、热力和微物理条件,可以作为人工增雨潜力区的判别指标。 相似文献
992.
磷石膏属于级配不良土且含有可溶性磷(P)、氟(F),在天然降雨的情况下其变形破坏的可能性很大。如其发生液化将充满整个渣库,这将使渣库内磷、氟含量升高而污染地表水体。在矿山的防渗等问题还未解决的情况下,受污染的地表水侵入到地下含水层中又会导致地下水的污染。所以研究磷石膏堆体在天然降雨下变形破坏模式十分必要。本试验是以1:10的比例模拟20m高的磷石膏堆体在天然降雨条件下可能发生的变形破坏模式,进而对渣库堆填磷石膏施工提出建议。 相似文献
993.
工程降水中人工回灌综合技术 总被引:6,自引:0,他引:6
建筑工程降水往往伴生水资源浪费和地面变形等环境问题,人工回灌是解决这些问题的有效手段之一。影响工程降水中人工回灌的条件有回灌场地水文地质条件、回灌水源水质和水量及回灌方案的经济可行性等因素。就工程降水中出现的问题,提出资源补充型回灌和应力稳定型回灌方法,并给出了适用条件; 根据工程降水水质特点及现有的地下水人工回灌相关水质标准,提出工程降水回灌水质的控制指标主要为悬浮物、浊度、一般污染性指标、微生物指标及重金属等。针对目前人工回灌在工程中存在的可回灌性低的问题,进行了影响入渗速率因素研究,为今后开展促渗关键技术提供理论支持。 相似文献
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996.
Rados?aw ?bikowski 《Estuarine, Coastal and Shelf Science》2011,94(2):138-143
This study demonstrates application of artificial neural networks (ANNs) for identifying the origin of green macroalgae (Enteromorpha sp. and Cladophora sp.) according to their concentrations of Cd, Cu, Ni, Zn, Mn, Pb, Na, Ca, K and Mg. Earlier studies confirmed that algae can be used for biomonitoring surveys of metal contaminants in coastal areas of the Southern Baltic. The same data sets were classified with the use of different structures of radial basis function (RBF) and multilayer perceptron (MLP) networks. The selected networks were able to classify the samples according to their geographical origin, i.e. Southern Baltic, Gulf of Gdańsk and Vistula Lagoon. Additionally in the case of macroalgae from the Gulf of Gdańsk, the networks enabled the discrimination of samples according to areas of contrasting levels of pollution. Hence this study shows that artificial neural networks can be a valuable tool in biomonitoring studies. 相似文献
997.
Elisa Cenci Matteo PizzolonNicole Chimento Carlotta Mazzoldi 《Estuarine, Coastal and Shelf Science》2011
Deployed for diverse purposes, artificial substrata can, theoretically, act as fish attractors or as fish producers. We tested these hypotheses by comparing fish assemblages on two artificial hard substrata, the Ca’ Roman and Sottomarina jetties, before (1994 and 2003) and after (2005 and 2006) the deployment of a new breakwater in the area. Our results support the fish production hypothesis. A remarkable increase in richness and abundance of sedentary species was observed on the extant substrata with the presence of the new barrier. More mobile species showed less definite trends. The net result has been a total increase in abundance and richness in the area. While fish assemblage showed important temporal variation in composition before deployment (Ca’ Roman, comparison between 1994 and 2003), clear trends of increasing abundance were concurrent with the presence of the new barrier. This increase in abundance, particularly of sedentary species, may be attributed to enhanced connectivity and/or an improvement in larval retention due to the changes in water circulation connected with the new breakwater, or to an increase in juveniles and/or adults promoted by changes in environmental conditions. Indeed, changes in benthic cover were recorded, with an increase of uncovered rock and the appearance of previously unrecorded algae after breakwater deployment. 相似文献
998.
To study population dynamics of marine ciliates in different artificial seawaters (ASW), the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater (NSW). The results show that: (1) the population growth rate was in the order of NSW>Flack ASW>Nakamula ASW>Schmadz ASW>Oshima ASW>Subow ASW and was considerably higher in rice media than in beef extract media (apart from Subow ASW); (2) the maximum density of E. vannus in stationary phase in each treatment was ranked as Flack ASW>Nakamula ASW>Schmadz ASW>NSW>Oshima ASW>Subow ASW, and was again higher in rice media than in beef extract media (except for Subow ASW); (3) the exponential and stationary phases were longer in rice media than in beef extract media; (4) strains of E. vannus that had been domesticated for >1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that: (1) E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW (mainly in terms of growth rate); and (2) Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology. 相似文献
999.
提出1种基于改进BP算法的风暴潮极值水位预报方法。首先针对现有人工神经网络BP算法存在的缺陷,引入Cauchy训练方法计算连接权的调整,解决BP算法的局部极小点和网络瘫痪的问题。然后结合山东海区水文观测站每年的台风风暴潮资料,应用该改进算法建立台风强度、风速和台风移速与风暴潮极值水位的非线性网络预报模型,对该站极值水位进行预报。实验结果表明,该算法具有很好的稳定性和准确性,为风暴潮预报分析提供了1种可靠的技术手段。 相似文献
1000.
临泽边缘绿洲区盐化草甸开垦后土壤质量演变 总被引:3,自引:2,他引:1
以黑河中游临泽边缘绿洲区为分析样区,研究了绿洲盐化草甸开垦后,不同开垦年限土壤的物理化学性状特征。结果表明,盐化草甸土壤中的黏粒从开垦前的9.18%增加到开垦30 a后的12.93%;除速效钾从开垦前的1315.50 mg·kg-1降至开垦30 a后的240.84 mg·kg-1外,土壤养分含量均有不同程度的增加;由于采取了工程、生物及农业措施来治理盐渍化,土壤全盐量明显降低,从开垦前的70.28 g·kg-1减至开垦30 a后的2.00 g·kg-1,减小了97.15%。土壤理化性状随开垦年限的增加而逐步改善。 相似文献