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681.
R. Thomas James Karl E. Havens 《Journal of the American Water Resources Association》1996,32(5):995-1006
ABSTRACT: Algal blooms, defined as chlorophyll α concentrations greater than 40 μg l?1, are common in Lake Okeechobee, Florida. Using logistic regression techniques, we have developed equations that relate limnological variables to algal bloom occurrence in four distinct open-water regions of this large shallow lake: central pelagic, northwest, southwest, and a transition region between the western and pelagic regions. Wind velocity and total phosphorus, which are closely related to resuspended material in the central region, are negatively related to algal bloom occurrence there. In the transition region, algal bloom occurrence is positively related to total nitrogen and wind velocity. Algal bloom occurrence is strongly and positively related to total nitrogen and total phosphorus concentrations in the western regions. The logistic regression model predicts an algal bloom probability greater than 95 percent in the northwest region when total phosphorus exceeds 0.10 mg l?1 and total nitrogen exceeds 2.5 mg l?1. In the southwest region the model predicts algal bloom probability of 100 percent when total phosphorus exceeds 0.10 mg l?1 and total nitrogen exceeds 2.8 mg l?1. Given 1994 mean total phosphorus concentrations of 0.05 and 0.04 mg l?1 in the northwest and southwest regions, respectively, total nitrogen would have to remain below 1.32 and 1.43 mg l?1, respectively, to keep the algal bloom probability below 10 percent. Because the lake is heterogenous, such nutrient standards should be considered on an in-lake regional basis for Lake Okeechobee. 相似文献
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湖南省环境质量演进的波动研究 总被引:3,自引:0,他引:3
环境库兹涅茨曲线是学术研究的热点问题,但是。对环境质量演进波动的研究还是空白。本文以湖南为例。运用计量分析及谱分析方法对湖南省环境质量演进中的波动性问题进行了尝试性实证研究。结果表明湖南环境质量的演进存在波动。且近年来各环境质量指标的波动有正向扩大的趋势;未来湖南环境质量周期波动亦将步入正向波动时期。因而。今后的发展可能会进一步加大对环境的压力。需要制定相应的环境政策来降低出现的大幅正向波动。 相似文献
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以江淮地区典型场地资料为原型,选取不同的土层分层厚度,构造多种场地土层计算模型,选择Taft、Kobe和El Centro三条强震记录作为地震输入,采用一维频域等效线性化波动方法分析了分层厚度对场地地表地震动参数的影响。研究表明:土层分层厚度对场地地震动参数存在影响,主要表现为采用较大分层厚度计算得到的地表峰值加速度A_(max)和反应谱特征周期T_g相对偏低,应采用尽可能小的土层分层厚度;分别采用1.0m和2.0m分层厚度计算得到的地表加速度反应谱形状基本重合,A_(max)和T_g也基本一致,最小选取2.0m土层分层厚度可以满足工程精度的要求。 相似文献
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Genevieve Simpson 《Local Environment》2018,23(2):127-143
Research into renewable energy adoption is increasingly identifying that the successful implementation of renewable energy projects is influenced by a combination of market, community and socio-political acceptance of renewable energy technology. This research uses case studies in two regional Australian communities to examine the social acceptance of residential solar energy, in particular under the influence of financial incentives and social interactions. Fifty-five semi-structured interviews with members of the local community, industry and government were undertaken between May and October 2015. Respondents were asked about their perceptions and knowledge of solar energy and incentives to support its adoption, and their interactions with actors important in the diffusion process. Responses indicated that financial incentives motivated solar adoption; however, social interactions in the communities also contributed to decision-making. In one case study, a local “solar champion” built a private solar farm to demonstrate the technical feasibility of solar, assisted community members with physically installing their own systems and helped community members to maximise the financial benefits of their solar installations. This solar champion contributed to this community having an earlier and more rapid rate of small-scale solar adoption compared with the second case study community. The second case study community included two individuals interested in promoting solar energy; however, they were less integrated with the community’s process of adopting solar, resulting in community members experiencing substandard installations and consequent distrust of the solar industry. This research concludes that local context influences solar adoption through complex interactions among market, community and socio-political acceptance. 相似文献
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Jingjing Fan Qiang Huang David M. Sumner Dingbao Wang 《International Journal of Green Energy》2018,15(9):497-506
Solar radiation is a major sustainable and clean energy resource, and use of solar radiation is expected to increase. The utilization efficiency of solar energy varies with the relative proportions of the direct and diffuse components that compose total solar radiation and with the slope and aspect of the irradiated surface. The purpose of this paper is to develop a simple method for estimating diffuse and direct solar radiation at sites with observation of only total solar radiation. An existing model for estimating diffuse radiation, i.e., a linear relationship between the diffuse fraction (the ratio of diffuse radiation to total solar radiation) and the clearness index (the ratio of total solar radiation to extraterrestrial radiation), is applied to 7 sites across the continental United States with observations of diffuse and total radiation. The linear model shows good monthly performance. The model parameters (slope and interception) show a strong seasonal pattern that exhibits small variation across the 7 sites; therefore, the average values of the two monthly parameters may be used for estimating diffuse radiation for other locations with observations of total radiation. 相似文献