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1.
基于GIS空间插值方法的长湖水质评价 总被引:2,自引:0,他引:2
通过对各插值方法选择后取反距离加权法与克立格法对长湖的污染现状进行分析,结果表明大部分水域水质处于Ⅴ类和劣Ⅴ类,只有主要出水口习家口和刘岺闸附近的部分水域的水质可以达到Ⅳ类水质标准.同时发现反距离加权法与克立格法均具有较高的精度,但克立格法优于反距离加权法,这两种方法评价湖泊水质都能取得比较好的效果. 相似文献
2.
Hot Spots of Perforated Forest in the Eastern United States 总被引:1,自引:0,他引:1
National assessments of forest fragmentation satisfy international biodiversity conventions, but they do not identify specific places where ecological impacts are likely. In this article, we identify geographic concentrations (hot spots) of forest located near holes in otherwise intact forest canopies (perforated forest) in the eastern United States, and we describe the proximate causes in terms of the nonforest land-cover types contained in those hot spots. Perforated forest, defined as a 0.09-ha unit of forest that is located at the center of a 7.29-ha neighborhood containing 60–99% forest with relatively low connectivity, was mapped over the eastern United States by using land-cover maps with roads superimposed. Statistically significant (P < 0.001) hot spots of high perforation rate (perforated area per unit area of forest) were then located by using a spatial scan statistic. Hot spots were widely distributed and covered 20.4% of the total area of the 10 ecological provinces examined, but 50.1% of the total hot-spot area was concentrated in only two provinces. In the central part of the study area, more than 90% of the forest edge in hot spots was attributed to anthropogenic land-cover types, whereas in the northern and southern parts it was more often associated with seminatural land cover such as herbaceous wetlands. 相似文献
3.
Christian Albert Mario Brillinger Paulina Guerrero Sarah Gottwald Jennifer Henze Stefan Schmidt Edward Ott Barbara Schrter 《Ambio》2021,50(8):1446
Nature-based solutions (NBS) find increasing attention as actions to address societal challenges through harnessing ecological processes, yet knowledge gaps exist regarding approaches to landscape planning with NBS. This paper aims to provide suggestions of how planning NBS can be conceptualized and applied in practice. We develop a framework for planning NBS by merging insights from literature and a case study in the Lahn river landscape, Germany. Our framework relates to three key criteria that define NBS, and consists of six steps of planning: Co-define setting, Understand challenges, Create visions and scenarios, Assess potential impacts, Develop solution strategies, and Realize and monitor. Its implementation is guided by five principles, namely Place-specificity, Evidence base, Integration, Equity, and Transdisciplinarity. Drawing on the empirical insights from the case study, we suggest suitable methods and a checklist of supportive procedures for applying the framework in practice. Taken together, our framework can facilitate planning NBS and provides further steps towards mainstreaming.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01365-1) contains supplementary material, which is available to authorized users. 相似文献
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在2010~2012年进行的上海某水源地水质监测资料的基础上,应用纳氏试剂分光光度法等分析方法研究该水源地2011年1~10月总氮、氨氮、硝酸盐氮、亚硝酸盐氮等不同形态的氮素在水体中的空间分布规律及时间变化规律。并就其氮的来源、迁移转化机理和对氮的迁移转化有较大影响的因素进行研究和分析,得出该水库水体中各种形态氮以硝酸盐氮为主,平均占总氮的71.6%,氨氮及亚硝酸盐氮各占总氮的4.39%及0.95%;水体中的温度、光照条件、溶解氧、点位位置分布、水深等是影响各氮形态含量与分布的重要环境因子。 相似文献
9.
Determining a remeasurement frequency of variables over time is required in monitoring environmental systems. This article
demonstrates methods based on regression modeling and spatio-temporal variability to determine the time interval to remeasure
the ground and vegetation cover factor on permanent plots for monitoring a soil erosion system. The spatio-temporal variability
methods include use of historical data to predict semivariograms, modeling average temporal variability, and temporal interpolation
by two-step kriging. The results show that for the cover factor, the relative errors of the prediction increase with an increased
length of time interval between remeasurements when using the regression and semivariogram models. Given precision or accuracy
requirements, appropriate time intervals can be determined. However, the remeasurement frequency also varies depending on
the prediction interval time. As an alternative method, the range parameter of a semivariogram model can be used to quantify
average temporal variability that approximates the maximum time interval between remeasurements. This method is simpler than
regression and semivariogram modeling, but it requires a long-term dataset based on permanent plots. In addition, the temporal
interpolation by two-step kriging is also used to determine the time interval. This method is applicable when remeasurements
in time are not sufficient. If spatial and temporal remeasurements are sufficient, it can be expanded and applied to design
spatial and temporal sampling simultaneously. 相似文献
10.
Improvements on Flood Alleviation in Germany: Lessons Learned from the Elbe Flood in August 2002 总被引:1,自引:0,他引:1
The increase in damage due to natural disasters is directly related to the number of people who live and work in hazardous
areas and continuously accumulate assets. Therefore, land use planning authorities have to manage effectively the establishment
and development of settlements in flood-prone areas in order to avoid the further increase of vulnerable assets. Germany faced
major destruction during the flood in August 2002 in the Elbe and Danube catchments, and many changes have been suggested
in the existing German water and planning regulations. This article presents some findings of a “Lessons Learned” study that
was carried out in the aftermath of the flood and discusses the following topics: 1) the establishment of comprehensive hazard
maps and flood protection concepts, 2) the harmonization of regulations of flood protection at the federal level, 3) the communication
of the flood hazard and awareness strategies, and 4) how damage potential can be minimized through measures of area precaution
such as resettlement and risk-adapted land use. Although attempts towards a coordinated and harmonized creation of flood hazard
maps and concepts have been made, there is still no uniform strategy at all planning levels and for all states (Lae
nder) of the Federal Republic of Germany. The development and communication of possible mitigation strategies for “unthinkable
extreme events” beyond the common safety level of a 100-year flood are needed. In order to establish a sustainable and integrated
flood risk management, interdisciplinary and catchment-based approaches are needed. 相似文献