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遥感信息融合是遥感数据处理的重要研究内容之一。在给出小波分解基本模型的基础上,采用IHS融合法、小波变换法对SPOT全色卫星影像数据和LandsatTM多光谱数据进行了融合处理,同时对实验结果进行了分析和讨论。 相似文献
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无人机遥感在水土保持领域的应用 总被引:3,自引:0,他引:3
我国水土流失面积大并分布广泛,传统水土保持研究调查方法已不能满足目前水土流失数据的获取需求。无人机遥感技术作为一种新型遥感数据获取手段,非常适合小范围内高分辨率遥感数据的即时获取,在水土保持领域的应用越加广泛。主要介绍了无人机遥感高分辨、高精度、高效率、低成本的应用特点,分析了无人机遥感数据获取和解译过程,总结了其在水土保持方案编制、动态监测、监督执法及设施验收评估等方面的具体应用,论述了该项技术在水土保持领域的重要性和发展前景。 相似文献
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针对高光谱曲线中可能存在噪声以及传统半经验方法不能有效利用全部光谱信息的问题,提出了耦合Haar小波变换和偏最小二乘的水质遥感高光谱建模方法(Haar WT-PLS)。利用该方法,对在南四湖获取的实测高光谱数据经分解尺度为3的Haar小波变换后,将原始光谱数据压缩到47个特征变量;随后利用小波变换重构的光谱数据建立了悬浮物浓度和浊度的Haar WT-PLS反演模型,并进行了验证。结果表明:Haar WT-PLS反演悬浮物浓度和浊度精度较高,验证样本的均方根误差分别为25.05 mg/L和20.10NTU,平均相对误差分别为20.36%和13.88%。通过和单波段模型、一阶微分模型和波段比值模型进行精度对比分析,本文建立的Haar WT-PLS模型反演悬浮物浓度和浊度具有较高的精度和更好的稳定性。 相似文献
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基于多尺度小波变换WNN的灌区灌溉水量研究 总被引:1,自引:0,他引:1
《人民黄河》2019,(11):154-158
选取Daubechies(db6)小波系对陆浑灌区1970—2013年的降水量及作物需水量时间序列进行多时间尺度水平分解,以得到的1970—2003年的小波系数为输入数据、灌溉水量为输出数据,构建多尺度小波变换的小波神经网络进行预测模拟,并利用单隐层BP、双隐层BP神经网络和小波神经网络分别进行了预测比较,结果表明:基于多尺度小波变换的小波神经网络模型的模拟精度和预测的稳定性均高于其他3种模型,4种预测模型的预测值平均相对误差排序为单隐层BP神经网络双隐层BP神经网络小波神经网络多尺度小波变换的小波神经网络。 相似文献
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遥感影像融合方法在ALOS影像水体信息提取中的应用研究 总被引:2,自引:0,他引:2
为了应用ALOS遥感影像调查浙江省德清县水域分布,首先采用小波变换、GS变换和高通滤波三种影像融合方法,分别对已配准的ALOS多光谱与全色波段影像进行融合;然后采用监督分类方法分别对融合前后影像提取水体信息,通过比较这三种融合方法在水体信息提取的效果,给出了适于水体信息提取的影像融合方法。 相似文献
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在介绍小波包变换算法的基础上,将小波包变换用于白噪声干扰下的气体绝缘组合电器(GIS)局部放电信号提取。对模拟的局部放电信号进行了小波包分解与重构的计算机仿真研究,分析了不同的局部放电波形、噪声水平及采样率对去噪结果的影响,最后对GIS内置传感器实测波形进行了小波包变换去噪。 相似文献
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The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L?1, the median total phosphorus was 0.29 mg L?1 and the median total nitrogen was 1.56 mg L?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd. 相似文献
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Carbon dioxide (CO2) and methane (CH4) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO2 and CH4 diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 106 t CO2eq km2 per year, or 24 × 106 t CO2eq per year. This corresponds to a plant emission factor of 3.18 kg CO2eq MWh?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO2eq per year, or 5.83 kg CO2eq MWh?1, which is in the lower range of the studied reservoirs. 相似文献
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《给水排水》2014,(9)
正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc. 相似文献
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River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept. 相似文献
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Peter M. Gibbs 《国际水》2013,38(4):547-557
Abstract A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies. 相似文献
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解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明:库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。 相似文献
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Mutlu Ozdogan Curtis E. Woodcock Guido D. Salvucci Hüseyin Demir 《Water Resources Management》2006,20(3):467-488
Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary
data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated
fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding
of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold
(from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area
from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate
a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a
volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes
in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future
water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation
due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation
conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation
sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead
to improved management, and by extension, sustainability of water resources in the region. 相似文献
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Suleyman A. Muyibi Abdul Raufu Ambali Garoot Suleiman Eissa 《Water Resources Management》2008,22(4):485-508
The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this
paper is not just to examine the trends of development-induced water pollution around the region of the country but to know
where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between
problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the
relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings
of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all
the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution
in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial
conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between
pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water
pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest
in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well
as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms
to comply with regulatory policies for water pollution control. 相似文献
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Intangible Flood Damage Quantification 总被引:3,自引:0,他引:3
Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology. 相似文献